1. Exhibit B - Signal Hill Housing Element Final EIR — Signal Hill City Council, July 12, 2022 (part 5 of 10)

Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/22/21 13:51
Town Center Northwest
Result Limit
Reporting
Units Level
Spike
Result
Source
%REC
%REC
Limits RPD
RPD
Analyte Limit Notes
Metals by EPA 6000/7000 Series Methods - Quality Control Sierra Analytical Labs, Inc.

Batch B1G1412 - EPA 3050B
Matrix Spike (B1G1412-MS1) Source: 2107188-21 Prepared: 07/14/21 Analyzed: 07/19/21 Antimony 87.8 8.0 mg/kg 97.5 ND 90.1 60-140
Chromium 100 2.3 " 97.5 7.00 95.6 70-130
Lead 91.1 7.1 " 97.5 1.24 92.2 70-130
Nickel 96.1 3.0 " 97.5 4.45 94.0 70-130
Beryllium 90.5 2.2 " 97.5 ND 92.8 70-130
Copper 96.9 5.0 " 97.5 4.43 94.9 70-130
Silver 91.4 2.0 " 97.5 ND 93.8 60-140
Barium 140 6.0 " 97.5 32.0 110 70-130
Cobalt 103 3.3 " 97.5 3.34 102 70-130
Arsenic 93.7 5.5 " 97.5 ND 96.1 70-130
Selenium 91.6 6.9 " 97.5 ND 94.0 70-130
Molybdenum 91.7 5.2 " 97.5 ND 94.1 70-130
Vanadium 99.3 5.1 " 97.5 9.20 92.4 70-130
Thallium 96.4 17 " 97.5 ND 98.9 70-130
Zinc 113 7.0 " 97.5 15.9 99.4 70-130
Cadmium 99.5 2.5 " 97.5 ND 102 70-130
Matrix Spike Dup (B1G1412-MSD1) Source: 2107188-21 Prepared: 07/14/21 Analyzed: 07/19/21 Cadmium 96.2 2.5 mg/kg 97.0 ND 99.2 70-130 3.32 20
Copper 111 5.0 " 97.0 4.43 110 70-130 14.0 30
Silver 91.1 2.0 " 97.0 ND 94.0 60-140 0.326 40
Arsenic 91.1 5.5 " 97.0 ND 93.9 70-130 2.80 20
Antimony 85.4 8.0 " 97.0 ND 88.0 60-140 2.84 20
Cobalt 101 3.3 " 97.0 3.34 100 70-130 2.40 20
Lead 88.7 7.1 " 97.0 1.24 90.2 70-130 2.65 30
Beryllium 88.7 2.2 " 97.0 ND 91.4 70-130 2.01 20
Molybdenum 89.6 5.2 " 97.0 ND 92.4 70-130 2.28 20
Thallium 93.5 17 " 97.0 ND 96.4 70-130 2.99 20
Selenium 89.1 6.9 " 97.0 ND 91.8 70-130 2.85 20
Vanadium 97.1 5.1 " 97.0 9.20 90.6 70-130 2.24 20
Barium 136 6.0 " 97.0 32.0 108 70-130 2.35 20
Chromium 102 2.3 " 97.0 7.00 98.2 70-130 2.04 20
Nickel 93.9 3.0 " 97.0 4.45 92.3 70-130 2.23 20
Zinc 111 7.0 " 97.0 15.9 97.7 70-130 1.94 20

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Batch B1G1413 - EPA 3050B
Blank (B1G1413-BLK1) Prepared: 07/14/21 Analyzed: 07/19/21 Selenium ND 6.9 mg/kg
Vanadium ND 5.1 "
Copper ND 5.0 "
Antimony ND 8.0 "
Silver ND 2.0 "
Lead ND 7.1 "
Molybdenum ND 5.2 "
Thallium ND 17 "
Cadmium ND 2.5 "
Arsenic ND 5.5 "
Cobalt ND 3.3 "
Nickel ND 3.0 "
Beryllium ND 2.2 "
Chromium ND 2.3 "
Barium ND 6.0 "
Zinc ND 7.0 "
LCS (B1G1413-BS1) Prepared: 07/14/21 Analyzed: 07/19/21 Chromium 99.8 2.3 mg/kg 100 99.8 80-120
Zinc 109 7.0 " 100 109 80-120
Barium 108 6.0 " 100 108 80-120
Vanadium 90.2 5.1 " 100 90.2 80-120
Beryllium 93.3 2.2 " 100 93.3 80-120
Nickel 101 3.0 " 100 101 80-120
Cadmium 106 2.5 " 100 106 80-120
Antimony 104 8.0 " 100 104 75-125
Selenium 102 6.9 " 100 102 76-124
Silver 107 2.0 " 100 107 60-140
Copper 96.1 5.0 " 100 96.1 78-122
Lead 102 7.1 " 100 102 80-120
Arsenic 103 5.5 " 100 103 78-122
Molybdenum 96.6 5.2 " 100 96.6 80-120
Thallium 108 17 " 100 108 80-120
Cobalt 111 3.3 " 100 111 80-120

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Batch B1G1413 - EPA 3050B
LCS Dup (B1G1413-BSD1) Prepared: 07/14/21 Analyzed: 07/19/21 Silver 108 2.0 mg/kg 100 108 60-140 1.37 40
Molybdenum 101 5.2 " 100 101 80-120 4.23 20
Nickel 98.9 3.0 " 100 98.9 80-120 1.93 20
Barium 107 6.0 " 100 107 80-120 1.32 20
Chromium 98.9 2.3 " 100 98.9 80-120 0.931 20
Lead 99.9 7.1 " 100 99.9 80-120 2.35 20
Thallium 107 17 " 100 107 80-120 0.535 20
Zinc 109 7.0 " 100 109 80-120 0.459 20
Cadmium 104 2.5 " 100 104 80-120 2.29 20
Arsenic 102 5.5 " 100 102 78-122 1.78 20
Antimony 101 8.0 " 100 101 75-125 2.83 20
Selenium 100 6.9 " 100 100 76-124 1.88 20
Vanadium 88.6 5.1 " 100 88.6 80-120 1.76 20
Beryllium 92.1 2.2 " 100 92.1 80-120 1.27 20
Cobalt 109 3.3 " 100 109 80-120 1.30 20
Copper 95.7 5.0 " 100 95.7 78-122 0.417 20
Matrix Spike (B1G1413-MS1) Source: 2107188-41 Prepared: 07/14/21 Analyzed: 07/19/21 Barium 185 6.0 mg/kg 99.2 65.7 120 70-130
Nickel 101 3.0 " 99.2 11.6 89.7 70-130
Zinc 137 7.0 " 99.2 34.9 103 70-130
Vanadium 110 5.1 " 99.2 22.6 88.4 70-130
Thallium 90.3 17 " 99.2 ND 91.0 70-130
Selenium 90.7 6.9 " 99.2 ND 91.5 70-130
Silver 108 2.0 " 99.2 ND 109 60-140
Lead 89.6 7.1 " 99.2 4.09 86.2 70-130
Molybdenum 83.6 5.2 " 99.2 0.725 83.5 70-130
Copper 97.7 5.0 " 99.2 12.2 86.2 70-130
Chromium 107 2.3 " 99.2 17.0 90.9 70-130
Cobalt 101 3.3 " 99.2 7.33 94.8 70-130
Beryllium 83.1 2.2 " 99.2 ND 83.8 70-130
Arsenic 93.8 5.5 " 99.2 ND 94.6 70-130
Antimony 73.9 8.0 " 99.2 ND 74.4 60-140
Cadmium 98.4 2.5 " 99.2 ND 99.2 70-130

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Batch B1G1413 - EPA 3050B
Matrix Spike Dup (B1G1413-MSD1) Source: 2107188-41 Prepared: 07/14/21 Analyzed: 07/19/21 Antimony 65.3 8.0 mg/kg 99.8 ND 65.4 60-140 12.3 20
Selenium 86.7 6.9 " 99.8 ND 86.9 70-130 4.56 20
Vanadium 103 5.1 " 99.8 22.6 80.7 70-130 6.68 20
Barium 172 6.0 " 99.8 65.7 107 70-130 7.03 20
Zinc 129 7.0 " 99.8 34.9 94.2 70-130 6.12 20
Arsenic 82.3 5.5 " 99.8 ND 82.5 70-130 13.1 20
Lead 79.1 7.1 " 99.8 4.09 75.2 70-130 12.4 30
Thallium 81.9 17 " 99.8 ND 82.0 70-130 9.75 20
Beryllium 77.9 2.2 " 99.8 ND 78.1 70-130 6.48 20
Cobalt 94.9 3.3 " 99.8 7.33 87.8 70-130 6.63 20
Chromium 100 2.3 " 99.8 17.0 83.3 70-130 6.76 20
Nickel 87.8 3.0 " 99.8 11.6 76.4 70-130 13.6 20
Cadmium 91.8 2.5 " 99.8 ND 92.0 70-130 6.88 20
Copper 110 5.0 " 99.8 12.2 97.9 70-130 11.7 30
Silver 104 2.0 " 99.8 ND 105 60-140 3.66 40
Molybdenum 95.4 5.2 " 99.8 0.725 94.8 70-130 13.1 20
Batch B1G1414 - EPA 7471A
Blank (B1G1414-BLK1) Prepared: 07/14/21 Analyzed: 07/16/21 Mercury ND 0.90 mg/kg
LCS (B1G1414-BS1) Prepared: 07/14/21 Analyzed: 07/16/21 Mercury 0.12 0.90 mg/kg 0.167 70.5 70-130
Matrix Spike (B1G1414-MS1) Source: 2107188-01 Prepared: 07/14/21 Analyzed: 07/16/21 Mercury 0.16 0.90 mg/kg 0.163 ND 100 70-130

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Batch B1G1414 - EPA 7471A
Matrix Spike Dup (B1G1414-MSD1) Source: 2107188-01 Prepared: 07/14/21 Analyzed: 07/16/21 Mercury 0.16 0.90 mg/kg 0.162 ND 99.9 70-130 0.871 30
Batch B1G1415 - EPA 7471A
Blank (B1G1415-BLK1) Prepared: 07/14/21 Analyzed: 07/16/21 Mercury ND 0.90 mg/kg
LCS (B1G1415-BS1) Prepared: 07/14/21 Analyzed: 07/16/21 Mercury 0.12 0.90 mg/kg 0.167 70.6 70-130
Matrix Spike (B1G1415-MS1) Source: 2107188-21 Prepared: 07/14/21 Analyzed: 07/16/21 Mercury 0.16 0.90 mg/kg 0.161 ND 101 70-130
Matrix Spike Dup (B1G1415-MSD1) Source: 2107188-21 Prepared: 07/14/21 Analyzed: 07/16/21 Mercury 0.16 0.90 mg/kg 0.158 ND 100 70-130 1.79 30
Batch B1G1416 - EPA 7471A
Blank (B1G1416-BLK1) Prepared: 07/14/21 Analyzed: 07/16/21 Mercury ND 0.90 mg/kg
LCS (B1G1416-BS1) Prepared: 07/14/21 Analyzed: 07/16/21 Mercury 0.12 0.90 mg/kg 0.167 70.7 70-130
Matrix Spike (B1G1416-MS1) Source: 2107188-41 Prepared: 07/14/21 Analyzed: 07/16/21 Mercury 0.20 0.90 mg/kg 0.161 ND 124 70-130

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Batch B1G1416 - EPA 7471A
Matrix Spike Dup (B1G1416-MSD1) Source: 2107188-41 Prepared: 07/14/21 Analyzed: 07/16/21 Mercury 0.19 0.90 mg/kg 0.158 ND 122 70-130 4.05 30
Batch B1G1417 - EPA 3060A
Blank (B1G1417-BLK1) Prepared: 07/14/21 Analyzed: 07/19/21 Hexavalent Chromium ND 0.10 mg/kg
LCS (B1G1417-BS1) Prepared: 07/14/21 Analyzed: 07/19/21 Hexavalent Chromium 0.161 0.10 mg/kg 0.150 107 80-120
Matrix Spike (B1G1417-MS1) Source: 2107188-01 Prepared: 07/14/21 Analyzed: 07/19/21 Hexavalent Chromium 0.200 0.10 mg/kg 0.149 0.0624 92.3 75-125 Matrix Spike Dup (B1G1417-MSD1) Source: 2107188-01 Prepared: 07/14/21 Analyzed: 07/19/21 Hexavalent Chromium 0.199 0.10 mg/kg 0.149 0.0624 91.4 75-125 0.823 20 Batch B1G1418 - EPA 3060A
Blank (B1G1418-BLK1) Prepared: 07/14/21 Analyzed: 07/19/21 Hexavalent Chromium ND 0.10 mg/kg
LCS (B1G1418-BS1) Prepared: 07/14/21 Analyzed: 07/19/21 Hexavalent Chromium 0.152 0.10 mg/kg 0.150 101 80-120
Matrix Spike (B1G1418-MS1) Source: 2107188-21 Prepared: 07/14/21 Analyzed: 07/19/21 Hexavalent Chromium 0.149 0.10 mg/kg 0.149 ND 99.9 75-125

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Reported:

Batch B1G1418 - EPA 3060A
Matrix Spike Dup (B1G1418-MSD1) Source: 2107188-21 Prepared: 07/14/21 Analyzed: 07/19/21 Hexavalent Chromium 0.142 0.10 mg/kg 0.149 ND 95.6 75-125 4.53 20 Batch B1G1419 - EPA 3060A
Blank (B1G1419-BLK1) Prepared: 07/14/21 Analyzed: 07/19/21 Hexavalent Chromium ND 0.10 mg/kg
LCS (B1G1419-BS1) Prepared: 07/14/21 Analyzed: 07/19/21 Hexavalent Chromium 0.144 0.10 mg/kg 0.150 96.2 80-120
Matrix Spike (B1G1419-MS1) Source: 2107188-41 Prepared: 07/14/21 Analyzed: 07/19/21 Hexavalent Chromium 0.146 0.10 mg/kg 0.145 0.0341 77.2 75-125 Matrix Spike Dup (B1G1419-MSD1) Source: 2107188-41 Prepared: 07/14/21 Analyzed: 07/19/21 Hexavalent Chromium 0.145 0.10 mg/kg 0.145 0.0341 76.9 75-125 0.525 20

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Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/22/21 13:51
Town Center Northwest
Result Limit
Reporting
Units Level
Spike
Result
Source
%REC
%REC
Limits RPD
RPD
Analyte Limit Notes
Total Petroleum Hydrocarbons Carbon Range Analysis by GC-FID - Quality Control Sierra Analytical Labs, Inc.

Batch B1G1502 - EPA 5035 P & T
Blank (B1G1502-BLK1) Prepared & Analyzed: 07/15/21
Total Petroleum Hydrocarbons (C4-C12) ND 0.050 mg/kg
LCS (B1G1502-BS1) Prepared & Analyzed: 07/15/21
Gasoline Range Hydrocarbons (C4-C12) 0.570 0.050 mg/kg 0.600 95.0 80-120 Matrix Spike (B1G1502-MS1) Source: 2107188-01 Prepared & Analyzed: 07/15/21 Gasoline Range Hydrocarbons (C4-C12) 0.455 0.050 mg/kg 0.600 ND 75.8 50-150 Matrix Spike Dup (B1G1502-MSD1) Source: 2107188-01 Prepared & Analyzed: 07/15/21 Gasoline Range Hydrocarbons (C4-C12) 0.480 0.050 mg/kg 0.600 ND 80.0 50-150 5.35 30 Batch B1G1503 - EPA 5035 P & T
Blank (B1G1503-BLK1) Prepared & Analyzed: 07/15/21
Total Petroleum Hydrocarbons (C4-C12) ND 0.050 mg/kg
LCS (B1G1503-BS1) Prepared & Analyzed: 07/15/21
Gasoline Range Hydrocarbons (C4-C12) 0.531 0.050 mg/kg 0.600 88.5 80-120 Matrix Spike (B1G1503-MS1) Source: 2107204-01 Prepared & Analyzed: 07/15/21 Gasoline Range Hydrocarbons (C4-C12) 0.466 0.050 mg/kg 0.600 ND 77.7 50-150 Matrix Spike Dup (B1G1503-MSD1) Source: 2107204-01 Prepared & Analyzed: 07/15/21 Gasoline Range Hydrocarbons (C4-C12) 0.371 0.050 mg/kg 0.600 ND 61.8 50-150 22.7 30 Batch B1G1504 - EPA 3550B Solid Ext
Blank (B1G1504-BLK1) Prepared & Analyzed: 07/15/21
Total Petroleum Hydrocarbons (C13-C22) ND 5.0 mg/kg
Total Petroleum Hydrocarbons (C23-C40) ND 5.0 "

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Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/22/21 13:51
Town Center Northwest
Result Limit
Reporting
Units Level
Spike
Result
Source
%REC
%REC
Limits RPD
RPD
Analyte Limit Notes
Total Petroleum Hydrocarbons Carbon Range Analysis by GC-FID - Quality Control Sierra Analytical Labs, Inc.

Batch B1G1504 - EPA 3550B Solid Ext
LCS (B1G1504-BS1) Prepared & Analyzed: 07/15/21
Diesel Range Organics (C10-C24) 18.1 5.0 mg/kg 20.0 90.7 80-120 Matrix Spike (B1G1504-MS1) Source: 2107188-01 Prepared & Analyzed: 07/15/21 Diesel Range Organics (C10-C24) 19.6 5.0 mg/kg 20.0 ND 98.1 50-150 Matrix Spike Dup (B1G1504-MSD1) Source: 2107188-01 Prepared & Analyzed: 07/15/21 Diesel Range Organics (C10-C24) 20.2 5.0 mg/kg 20.0 ND 101 50-150 2.77 30 Batch B1G1601 - EPA 3550B Solid Ext
Blank (B1G1601-BLK1) Prepared: 07/15/21 Analyzed: 07/16/21 Total Petroleum Hydrocarbons (C13-C22) ND 5.0 mg/kg
Total Petroleum Hydrocarbons (C23-C40) ND 5.0 "
LCS (B1G1601-BS1) Prepared: 07/15/21 Analyzed: 07/16/21 Diesel Range Organics (C10-C24) 16.3 5.0 mg/kg 20.0 81.5 80-120 Matrix Spike (B1G1601-MS1) Source: 2107204-01 Prepared: 07/15/21 Analyzed: 07/16/21 Diesel Range Organics (C10-C24) 19.7 5.0 mg/kg 20.0 ND 98.6 50-150 Matrix Spike Dup (B1G1601-MSD1) Source: 2107204-01 Prepared: 07/15/21 Analyzed: 07/16/21 Diesel Range Organics (C10-C24) 22.5 5.0 mg/kg 20.0 ND 112 50-150 13.1 30 Batch B1G1602 - EPA 3550B Solid Ext
Blank (B1G1602-BLK1) Prepared: 07/15/21 Analyzed: 07/16/21 Total Petroleum Hydrocarbons (C13-C22) ND 5.0 mg/kg
Total Petroleum Hydrocarbons (C23-C40) ND 5.0 "

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Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/22/21 13:51
Town Center Northwest
Result Limit
Reporting
Units Level
Spike
Result
Source
%REC
%REC
Limits RPD
RPD
Analyte Limit Notes
Total Petroleum Hydrocarbons Carbon Range Analysis by GC-FID - Quality Control Sierra Analytical Labs, Inc.

Batch B1G1602 - EPA 3550B Solid Ext
LCS (B1G1602-BS1) Prepared: 07/15/21 Analyzed: 07/16/21 Diesel Range Organics (C10-C24) 16.9 5.0 mg/kg 20.0 84.7 80-120 Matrix Spike (B1G1602-MS1) Source: 2107188-23 Prepared: 07/15/21 Analyzed: 07/16/21 Diesel Range Organics (C10-C24) 16.0 5.0 mg/kg 20.0 ND 79.8 50-150 Matrix Spike Dup (B1G1602-MSD1) Source: 2107188-23 Prepared: 07/15/21 Analyzed: 07/16/21 Diesel Range Organics (C10-C24) 18.3 5.0 mg/kg 20.0 ND 91.4 50-150 13.6 30 Batch B1G1913 - EPA 5035 P & T
Blank (B1G1913-BLK1) Prepared: 07/19/21 Analyzed: 07/20/21 Total Petroleum Hydrocarbons (C4-C12) ND 0.050 mg/kg
LCS (B1G1913-BS1) Prepared: 07/19/21 Analyzed: 07/20/21 Gasoline Range Hydrocarbons (C4-C12) 0.697 0.050 mg/kg 0.600 116 80-120 Matrix Spike (B1G1913-MS1) Source: 2107188-23 Prepared: 07/19/21 Analyzed: 07/20/21 Gasoline Range Hydrocarbons (C4-C12) 0.570 0.050 mg/kg 0.600 ND 95.0 50-150 Matrix Spike Dup (B1G1913-MSD1) Source: 2107188-23 Prepared: 07/19/21 Analyzed: 07/20/21 Gasoline Range Hydrocarbons (C4-C12) 0.456 0.050 mg/kg 0.600 ND 76.0 50-150 22.2 30

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Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/22/21 13:51
Town Center Northwest
Result Limit
Reporting
Units Level
Spike
Result
Source
%REC
%REC
Limits RPD
RPD
Analyte Limit Notes
Volatile Organic Compounds by EPA Method 8260B - Quality Control Sierra Analytical Labs, Inc.

Batch B1G1407 - EPA 5035 P & T
Blank (B1G1407-BLK1) Prepared: 07/14/21 Analyzed: 07/15/21 Benzene ND 5.0 µg/kg
Bromobenzene ND 5.0 "
Bromochloromethane ND 5.0 "
Bromodichloromethane ND 5.0 "
Bromoform ND 5.0 "
Bromomethane ND 5.0 "
n-Butylbenzene ND 5.0 "
sec-Butylbenzene ND 5.0 "
tert-Butylbenzene ND 5.0 "
Carbon tetrachloride ND 5.0 "
Chlorobenzene ND 5.0 "
Chloroethane ND 5.0 "
Chloroform ND 5.0 "
Chloromethane ND 5.0 "
2-Chlorotoluene ND 5.0 "
4-Chlorotoluene ND 5.0 "
Dibromochloromethane ND 5.0 "
1,2-Dibromo-3-chloropropane ND 5.0 "
1,2-Dibromoethane (EDB) ND 5.0 "
Dibromomethane ND 5.0 "
1,2-Dichlorobenzene ND 5.0 "
1,3-Dichlorobenzene ND 5.0 "
1,4-Dichlorobenzene ND 5.0 "
Dichlorodifluoromethane ND 5.0 "
1,1-Dichloroethane ND 5.0 "
1,2-Dichloroethane ND 5.0 "
1,1-Dichloroethene ND 5.0 "
cis-1,2-Dichloroethene ND 5.0 "
trans-1,2-Dichloroethene ND 5.0 "
1,2-Dichloropropane ND 5.0 "
1,3-Dichloropropane ND 5.0 "
2,2-Dichloropropane ND 5.0 "
1,1-Dichloropropene ND 5.0 "
cis-1,3-Dichloropropene ND 5.0 "
trans-1,3-Dichloropropene ND 5.0 "
Ethylbenzene ND 5.0 "
Hexachlorobutadiene ND 5.0 "

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Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/22/21 13:51
Town Center Northwest
Result Limit
Reporting
Units Level
Spike
Result
Source
%REC
%REC
Limits RPD
RPD
Analyte Limit Notes
Volatile Organic Compounds by EPA Method 8260B - Quality Control Sierra Analytical Labs, Inc.

Batch B1G1407 - EPA 5035 P & T
Blank (B1G1407-BLK1) Prepared: 07/14/21 Analyzed: 07/15/21 Isopropylbenzene ND 5.0 µg/kg
p-Isopropyltoluene ND 5.0 "
Methylene chloride ND 5.0 "
Methyl tert-butyl ether ND 5.0 "
Naphthalene ND 5.0 "
n-Propylbenzene ND 5.0 "
Styrene ND 5.0 "
1,1,1,2-Tetrachloroethane ND 5.0 "
1,1,2,2-Tetrachloroethane ND 5.0 "
Tetrachloroethene ND 5.0 "
Toluene ND 5.0 "
1,2,3-Trichlorobenzene ND 5.0 "
1,2,4-Trichlorobenzene ND 5.0 "
1,1,1-Trichloroethane ND 5.0 "
1,1,2-Trichloroethane ND 5.0 "
Trichloroethene ND 5.0 "
Trichlorofluoromethane ND 5.0 "
1,2,3-Trichloropropane ND 5.0 "
1,2,4-Trimethylbenzene ND 5.0 "
1,3,5-Trimethylbenzene ND 5.0 "
Vinyl chloride ND 5.0 "
m,p-Xylene ND 5.0 "
o-Xylene ND 5.0 "
LCS (B1G1407-BS1) Prepared: 07/14/21 Analyzed: 07/15/21 Benzene 50.3 5.0 µg/kg 50.0 101 80-120
Chlorobenzene 40.1 5.0 " 50.0 80.2 80-120
1,1-Dichloroethene 49.0 5.0 " 50.0 98.0 80-120
Toluene 42.3 5.0 " 50.0 84.7 80-120
Trichloroethene 50.2 5.0 " 50.0 100 80-120

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Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/22/21 13:51
Town Center Northwest
Result Limit
Reporting
Units Level
Spike
Result
Source
%REC
%REC
Limits RPD
RPD
Analyte Limit Notes
Volatile Organic Compounds by EPA Method 8260B - Quality Control Sierra Analytical Labs, Inc.

Batch B1G1407 - EPA 5035 P & T
Matrix Spike (B1G1407-MS1) Source: 2107188-01 Prepared: 07/14/21 Analyzed: 07/15/21 Benzene 49.1 5.0 µg/kg 50.0 ND 98.2 37-151
Chlorobenzene 38.2 5.0 " 50.0 ND 76.4 37-160
1,1-Dichloroethene 48.0 5.0 " 50.0 ND 96.0 50-150
Toluene 40.2 5.0 " 50.0 ND 80.3 47-150
Trichloroethene 48.1 5.0 " 50.0 ND 96.2 71-157
Matrix Spike Dup (B1G1407-MSD1) Source: 2107188-01 Prepared: 07/14/21 Analyzed: 07/15/21 Benzene 47.4 5.0 µg/kg 50.0 ND 94.8 37-151 3.56 30
Chlorobenzene 36.9 5.0 " 50.0 ND 73.9 37-160 3.33 30
1,1-Dichloroethene 44.6 5.0 " 50.0 ND 89.2 50-150 7.37 30 Toluene 37.8 5.0 " 50.0 ND 75.5 47-150 6.14 30
Trichloroethene 46.2 5.0 " 50.0 ND 92.5 71-157 3.92 30
Batch B1G1505 - EPA 5035 P & T
Blank (B1G1505-BLK1) Prepared & Analyzed: 07/15/21
Benzene ND 5.0 µg/kg
Bromobenzene ND 5.0 "
Bromochloromethane ND 5.0 "
Bromodichloromethane ND 5.0 "
Bromoform ND 5.0 "
Bromomethane ND 5.0 "
n-Butylbenzene ND 5.0 "
sec-Butylbenzene ND 5.0 "
tert-Butylbenzene ND 5.0 "
Carbon tetrachloride ND 5.0 "
Chlorobenzene ND 5.0 "
Chloroethane ND 5.0 "
Chloroform ND 5.0 "
Chloromethane ND 5.0 "
2-Chlorotoluene ND 5.0 "
4-Chlorotoluene ND 5.0 "
Dibromochloromethane ND 5.0 "
1,2-Dibromo-3-chloropropane ND 5.0 "
1,2-Dibromoethane (EDB) ND 5.0 "
Dibromomethane ND 5.0 "
1,2-Dichlorobenzene ND 5.0 "
1,3-Dichlorobenzene ND 5.0 "

Page 206 of 220 ends

Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/22/21 13:51
Town Center Northwest
Result Limit
Reporting
Units Level
Spike
Result
Source
%REC
%REC
Limits RPD
RPD
Analyte Limit Notes
Volatile Organic Compounds by EPA Method 8260B - Quality Control Sierra Analytical Labs, Inc.

Batch B1G1505 - EPA 5035 P & T
Blank (B1G1505-BLK1) Prepared & Analyzed: 07/15/21
1,4-Dichlorobenzene ND 5.0 µg/kg
Dichlorodifluoromethane ND 5.0 "
1,1-Dichloroethane ND 5.0 "
1,2-Dichloroethane ND 5.0 "
1,1-Dichloroethene ND 5.0 "
cis-1,2-Dichloroethene ND 5.0 "
trans-1,2-Dichloroethene ND 5.0 "
1,2-Dichloropropane ND 5.0 "
1,3-Dichloropropane ND 5.0 "
2,2-Dichloropropane ND 5.0 "
1,1-Dichloropropene ND 5.0 "
cis-1,3-Dichloropropene ND 5.0 "
trans-1,3-Dichloropropene ND 5.0 "
Ethylbenzene ND 5.0 "
Hexachlorobutadiene ND 5.0 "
Isopropylbenzene ND 5.0 "
p-Isopropyltoluene ND 5.0 "
Methylene chloride ND 5.0 "
Methyl tert-butyl ether ND 5.0 "
Naphthalene ND 5.0 "
n-Propylbenzene ND 5.0 "
Styrene ND 5.0 "
1,1,1,2-Tetrachloroethane ND 5.0 "
1,1,2,2-Tetrachloroethane ND 5.0 "
Tetrachloroethene ND 5.0 "
Toluene ND 5.0 "
1,2,3-Trichlorobenzene ND 5.0 "
1,2,4-Trichlorobenzene ND 5.0 "
1,1,1-Trichloroethane ND 5.0 "
1,1,2-Trichloroethane ND 5.0 "
Trichloroethene ND 5.0 "
Trichlorofluoromethane ND 5.0 "
1,2,3-Trichloropropane ND 5.0 "
1,2,4-Trimethylbenzene ND 5.0 "
1,3,5-Trimethylbenzene ND 5.0 "
Vinyl chloride ND 5.0 "
m,p-Xylene ND 5.0 "

Page 207 of 220 ends

Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/22/21 13:51
Town Center Northwest
Result Limit
Reporting
Units Level
Spike
Result
Source
%REC
%REC
Limits RPD
RPD
Analyte Limit Notes
Volatile Organic Compounds by EPA Method 8260B - Quality Control Sierra Analytical Labs, Inc.

Batch B1G1505 - EPA 5035 P & T
Blank (B1G1505-BLK1) Prepared & Analyzed: 07/15/21
o-Xylene ND 5.0 µg/kg
LCS (B1G1505-BS1) Prepared & Analyzed: 07/15/21
Benzene 48.1 5.0 µg/kg 50.0 96.2 80-120
Chlorobenzene 47.1 5.0 " 50.0 94.2 80-120
1,1-Dichloroethene 45.5 5.0 " 50.0 90.9 80-120
Toluene 40.0 5.0 " 50.0 80.0 80-120
Trichloroethene 54.0 5.0 " 50.0 108 80-120
Matrix Spike (B1G1505-MS1) Source: 2107188-21 Prepared & Analyzed: 07/15/21 Benzene 47.2 5.0 µg/kg 50.0 ND 94.5 37-151
Chlorobenzene 41.2 5.0 " 50.0 ND 82.3 37-160
1,1-Dichloroethene 42.9 5.0 " 50.0 ND 85.8 50-150
Toluene 43.1 5.0 " 50.0 ND 86.3 47-150
Trichloroethene 55.4 5.0 " 50.0 ND 111 71-157
Matrix Spike Dup (B1G1505-MSD1) Source: 2107188-21 Prepared & Analyzed: 07/15/21 Benzene 48.8 5.0 µg/kg 50.0 ND 97.6 37-151 3.23 30
Chlorobenzene 41.6 5.0 " 50.0 ND 83.2 37-160 1.04 30
1,1-Dichloroethene 44.7 5.0 " 50.0 ND 89.4 50-150 4.13 30 Toluene 45.5 5.0 " 50.0 ND 90.9 47-150 5.26 30
Trichloroethene 56.1 5.0 " 50.0 ND 112 71-157 1.18 30
Batch B1G1507 - EPA 5035 P & T
Blank (B1G1507-BLK1) Prepared: 07/16/21 Analyzed: 07/19/21 Benzene ND 5.0 µg/kg
Bromobenzene ND 5.0 "
Bromochloromethane ND 5.0 "
Bromodichloromethane ND 5.0 "
Bromoform ND 5.0 "
Bromomethane ND 5.0 "
n-Butylbenzene ND 5.0 "
sec-Butylbenzene ND 5.0 "
tert-Butylbenzene ND 5.0 "
Carbon tetrachloride ND 5.0 "
Chlorobenzene ND 5.0 "
Chloroethane ND 5.0 "
Chloroform ND 5.0 "

Page 208 of 220 ends

Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/22/21 13:51
Town Center Northwest
Result Limit
Reporting
Units Level
Spike
Result
Source
%REC
%REC
Limits RPD
RPD
Analyte Limit Notes
Volatile Organic Compounds by EPA Method 8260B - Quality Control Sierra Analytical Labs, Inc.

Batch B1G1507 - EPA 5035 P & T
Blank (B1G1507-BLK1) Prepared: 07/16/21 Analyzed: 07/19/21 Chloromethane ND 5.0 µg/kg
2-Chlorotoluene ND 5.0 "
4-Chlorotoluene ND 5.0 "
Dibromochloromethane ND 5.0 "
1,2-Dibromo-3-chloropropane ND 5.0 "
1,2-Dibromoethane (EDB) ND 5.0 "
Dibromomethane ND 5.0 "
1,2-Dichlorobenzene ND 5.0 "
1,3-Dichlorobenzene ND 5.0 "
1,4-Dichlorobenzene ND 5.0 "
Dichlorodifluoromethane ND 5.0 "
1,1-Dichloroethane ND 5.0 "
1,2-Dichloroethane ND 5.0 "
1,1-Dichloroethene ND 5.0 "
cis-1,2-Dichloroethene ND 5.0 "
trans-1,2-Dichloroethene ND 5.0 "
1,2-Dichloropropane ND 5.0 "
1,3-Dichloropropane ND 5.0 "
2,2-Dichloropropane ND 5.0 "
1,1-Dichloropropene ND 5.0 "
cis-1,3-Dichloropropene ND 5.0 "
trans-1,3-Dichloropropene ND 5.0 "
Ethylbenzene ND 5.0 "
Hexachlorobutadiene ND 5.0 "
Isopropylbenzene ND 5.0 "
p-Isopropyltoluene ND 5.0 "
Methylene chloride ND 5.0 "
Methyl tert-butyl ether ND 5.0 "
Naphthalene ND 5.0 "
n-Propylbenzene ND 5.0 "
Styrene ND 5.0 "
1,1,1,2-Tetrachloroethane ND 5.0 "
1,1,2,2-Tetrachloroethane ND 5.0 "
Tetrachloroethene ND 5.0 "
Toluene ND 5.0 "
1,2,3-Trichlorobenzene ND 5.0 "
1,2,4-Trichlorobenzene ND 5.0 "

Page 209 of 220 ends

Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/22/21 13:51
Town Center Northwest
Result Limit
Reporting
Units Level
Spike
Result
Source
%REC
%REC
Limits RPD
RPD
Analyte Limit Notes
Volatile Organic Compounds by EPA Method 8260B - Quality Control Sierra Analytical Labs, Inc.

Batch B1G1507 - EPA 5035 P & T
Blank (B1G1507-BLK1) Prepared: 07/16/21 Analyzed: 07/19/21 1,1,1-Trichloroethane ND 5.0 µg/kg
1,1,2-Trichloroethane ND 5.0 "
Trichloroethene ND 5.0 "
Trichlorofluoromethane ND 5.0 "
1,2,3-Trichloropropane ND 5.0 "
1,2,4-Trimethylbenzene ND 5.0 "
1,3,5-Trimethylbenzene ND 5.0 "
Vinyl chloride ND 5.0 "
m,p-Xylene ND 5.0 "
o-Xylene ND 5.0 "
LCS (B1G1507-BS1) Prepared: 07/16/21 Analyzed: 07/19/21 Benzene 48.2 5.0 µg/kg 50.0 96.4 80-120
Chlorobenzene 47.1 5.0 " 50.0 94.2 80-120
1,1-Dichloroethene 44.3 5.0 " 50.0 88.6 80-120
Toluene 42.8 5.0 " 50.0 85.7 80-120
Trichloroethene 50.8 5.0 " 50.0 102 80-120
Matrix Spike (B1G1507-MS1) Source: 2107118-05 Prepared: 07/16/21 Analyzed: 07/19/21 Benzene 40.2 5.0 µg/kg 50.0 ND 80.4 37-151
Chlorobenzene 34.2 5.0 " 50.0 ND 68.4 37-160
1,1-Dichloroethene 36.1 5.0 " 50.0 ND 72.3 50-150
Toluene 36.4 5.0 " 50.0 ND 72.7 47-150
Trichloroethene 43.2 5.0 " 50.0 ND 86.5 71-157
Matrix Spike Dup (B1G1507-MSD1) Source: 2107118-05 Prepared: 07/16/21 Analyzed: 07/19/21 Benzene 44.9 5.0 µg/kg 50.0 ND 89.8 37-151 11.0 30
Chlorobenzene 37.3 5.0 " 50.0 ND 74.6 37-160 8.73 30
1,1-Dichloroethene 39.1 5.0 " 50.0 ND 78.1 50-150 7.79 30 Toluene 39.4 5.0 " 50.0 ND 78.9 47-150 8.12 30
Trichloroethene 48.5 5.0 " 50.0 ND 97.0 71-157 11.4 30

Page 210 of 220 ends

Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/22/21 13:51
Town Center Northwest
Result Limit
Reporting
Units Level
Spike
Result
Source
%REC
%REC
Limits RPD
RPD
Analyte Limit Notes
Semivolatile Organic Compounds by EPA Method 8270C - Quality Control Sierra Analytical Labs, Inc.

Batch B1G1603 - EPA 3550B Solid Ext
Blank (B1G1603-BLK1) Prepared: 07/15/21 Analyzed: 07/16/21 Acenaphthene ND 0.33 mg/kg
Acenaphthylene ND 0.33 "
Anthracene ND 0.33 "
Benzidine ND 0.33 "
Benzo (a) anthracene ND 0.33 "
Benzo (b) fluoranthene ND 0.33 "
Benzo (k) fluoranthene ND 0.33 "
Benzo (a) pyrene ND 0.33 "
Benzo (g,h,i) perylene ND 0.33 "
Benzyl alcohol ND 0.33 "
Bis(2-chloroethyl)ether ND 0.33 "
Bis(2-chloroethoxy)methane ND 0.33 "
Bis(2-ethylhexyl)phthalate ND 0.33 "
Bis(2-chloroisopropyl)ether ND 0.33 "
4-Bromophenyl phenyl ether ND 0.33 "
Butyl benzyl phthalate ND 0.33 "
4-Chloroaniline ND 0.33 "
2-Chlorophenol ND 0.33 "
4-Chloro-3-methylphenol ND 0.33 "
2-Chloronaphthalene ND 0.33 "
4-Chlorophenyl phenyl ether ND 0.33 "
Chrysene ND 0.33 "
Dibenz (a,h) anthracene ND 0.33 "
Dibenzofuran ND 0.33 "
1,3-Dichlorobenzene ND 0.33 "
1,2-Dichlorobenzene ND 0.33 "
1,4-Dichlorobenzene ND 0.33 "
3,3´-Dichlorobenzidine ND 0.33 "
2,4-Dichlorophenol ND 0.33 "
Diethyl phthalate ND 0.33 "
2,4-Dimethylphenol ND 0.33 "
Dimethyl phthalate ND 0.33 "
Di-n-butyl phthalate ND 0.33 "
2,4-Dinitrophenol ND 0.33 "
4,6-Dinitro-2-methylphenol ND 0.33 "
2,4-Dinitrotoluene ND 0.33 "
2,6-Dinitrotoluene ND 0.33 "

Page 211 of 220 ends

Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/22/21 13:51
Town Center Northwest
Result Limit
Reporting
Units Level
Spike
Result
Source
%REC
%REC
Limits RPD
RPD
Analyte Limit Notes
Semivolatile Organic Compounds by EPA Method 8270C - Quality Control Sierra Analytical Labs, Inc.

Batch B1G1603 - EPA 3550B Solid Ext
Blank (B1G1603-BLK1) Prepared: 07/15/21 Analyzed: 07/16/21 Di-n-octyl phthalate ND 0.33 mg/kg
1,2-Diphenylhydrazine ND 0.33 "
Fluoranthene ND 0.33 "
Fluorene ND 0.33 "
Hexachlorobenzene ND 0.33 "
Hexachlorobutadiene ND 0.33 "
Hexachlorocyclopentadiene ND 0.33 "
Hexachloroethane ND 0.33 "
Indeno (1,2,3-cd) pyrene ND 0.33 "
Isophorone ND 0.33 "
2-Methylnaphthalene ND 0.33 "
2-Methylphenol ND 0.33 "
4-Methylphenol ND 0.33 "
Naphthalene ND 0.33 "
2-Nitroaniline ND 0.33 "
3-Nitroaniline ND 0.33 "
4-Nitroaniline ND 0.33 "
Nitrobenzene ND 0.33 "
2-Nitrophenol ND 0.33 "
4-Nitrophenol ND 0.33 "
N-Nitrosodimethylamine ND 0.33 "
Diphenylamine ND 0.33 "
N-Nitrosodi-n-propylamine ND 0.33 "
Pentachlorophenol ND 0.33 "
Phenanthrene ND 0.33 "
Phenol ND 0.33 "
Pyrene ND 0.33 "
1,2,4-Trichlorobenzene ND 0.33 "
2,4,5-Trichlorophenol ND 0.33 "
2,4,6-Trichlorophenol ND 0.33 "

Page 212 of 220 ends

Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/22/21 13:51
Town Center Northwest
Result Limit
Reporting
Units Level
Spike
Result
Source
%REC
%REC
Limits RPD
RPD
Analyte Limit Notes
Semivolatile Organic Compounds by EPA Method 8270C - Quality Control Sierra Analytical Labs, Inc.

Batch B1G1603 - EPA 3550B Solid Ext
LCS (B1G1603-BS1) Prepared: 07/15/21 Analyzed: 07/16/21 Acenaphthene 0.843 0.33 mg/kg 1.00 84.3 47-145
2-Chlorophenol 2.07 0.33 " 2.00 104 23-134
4-Chloro-3-methylphenol 1.94 0.33 " 2.00 96.8 22-147
1,4-Dichlorobenzene 0.791 0.33 " 1.00 79.1 20-124
2,4-Dinitrotoluene 0.496 0.33 " 1.00 49.6 39-139
4-Nitrophenol 0.636 0.33 " 2.00 31.8 0-132
N-Nitrosodi-n-propylamine 0.683 0.33 " 1.00 68.3 0-230
Pentachlorophenol 0.446 0.33 " 2.00 22.3 14-176
Phenol 1.73 0.33 " 2.00 86.4 5-112
Pyrene 0.831 0.33 " 1.00 83.1 52-115
1,2,4-Trichlorobenzene 0.729 0.33 " 1.00 72.9 44-142
Matrix Spike (B1G1603-MS1) Source: 2107188-01 Prepared: 07/15/21 Analyzed: 07/16/21 Acenaphthene 0.909 0.33 mg/kg 1.00 ND 90.9 47-145
2-Chlorophenol 1.84 0.33 " 2.00 ND 91.8 23-134
4-Chloro-3-methylphenol 1.65 0.33 " 2.00 ND 82.6 22-147 1,4-Dichlorobenzene 0.894 0.33 " 1.00 ND 89.4 20-124
2,4-Dinitrotoluene 0.537 0.33 " 1.00 ND 53.7 39-139
4-Nitrophenol 0.655 0.33 " 2.00 ND 32.8 0-132
N-Nitrosodi-n-propylamine 0.881 0.33 " 1.00 ND 88.1 0-230 Pentachlorophenol 0.351 0.33 " 2.00 ND 17.6 14-176
Phenol 1.59 0.33 " 2.00 ND 79.5 5-112
Pyrene 0.953 0.33 " 1.00 ND 95.3 52-115
1,2,4-Trichlorobenzene 0.820 0.33 " 1.00 ND 82.0 44-142 Matrix Spike Dup (B1G1603-MSD1) Source: 2107188-01 Prepared: 07/15/21 Analyzed: 07/16/21 Acenaphthene 1.03 0.33 mg/kg 1.00 ND 103 47-145 12.8 30 2-Chlorophenol 1.90 0.33 " 2.00 ND 95.0 23-134 3.37 30
4-Chloro-3-methylphenol 1.90 0.33 " 2.00 ND 94.8 22-147 13.7 30 1,4-Dichlorobenzene 0.981 0.33 " 1.00 ND 98.1 20-124 9.28 30 2,4-Dinitrotoluene 0.527 0.33 " 1.00 ND 52.7 39-139 1.88 30 4-Nitrophenol 0.642 0.33 " 2.00 ND 32.1 0-132 2.00 30
N-Nitrosodi-n-propylamine 0.938 0.33 " 1.00 ND 93.8 0-230 6.27 30 Pentachlorophenol 0.414 0.33 " 2.00 ND 20.7 14-176 16.5 30 Phenol 1.84 0.33 " 2.00 ND 92.1 5-112 14.7 30
Pyrene 0.846 0.33 " 1.00 ND 84.6 52-115 11.9 30
1,2,4-Trichlorobenzene 0.708 0.33 " 1.00 ND 70.8 44-142 14.7 30

Page 213 of 220 ends

Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/22/21 13:51
Town Center Northwest
Result Limit
Reporting
Units Level
Spike
Result
Source
%REC
%REC
Limits RPD
RPD
Analyte Limit Notes
Semivolatile Organic Compounds by EPA Method 8270C - Quality Control Sierra Analytical Labs, Inc.

Batch B1G1916 - EPA 3550B Solid Ext
Blank (B1G1916-BLK1) Prepared: 07/19/21 Analyzed: 07/20/21 Acenaphthene ND 0.33 mg/kg
Acenaphthylene ND 0.33 "
Anthracene ND 0.33 "
Benzidine ND 0.33 "
Benzo (a) anthracene ND 0.33 "
Benzo (b) fluoranthene ND 0.33 "
Benzo (k) fluoranthene ND 0.33 "
Benzo (a) pyrene ND 0.33 "
Benzo (g,h,i) perylene ND 0.33 "
Benzyl alcohol ND 0.33 "
Bis(2-chloroethyl)ether ND 0.33 "
Bis(2-chloroethoxy)methane ND 0.33 "
Bis(2-ethylhexyl)phthalate ND 0.33 "
Bis(2-chloroisopropyl)ether ND 0.33 "
4-Bromophenyl phenyl ether ND 0.33 "
Butyl benzyl phthalate ND 0.33 "
4-Chloroaniline ND 0.33 "
2-Chlorophenol ND 0.33 "
4-Chloro-3-methylphenol ND 0.33 "
2-Chloronaphthalene ND 0.33 "
4-Chlorophenyl phenyl ether ND 0.33 "
Chrysene ND 0.33 "
Dibenz (a,h) anthracene ND 0.33 "
Dibenzofuran ND 0.33 "
1,3-Dichlorobenzene ND 0.33 "
1,2-Dichlorobenzene ND 0.33 "
1,4-Dichlorobenzene ND 0.33 "
3,3´-Dichlorobenzidine ND 0.33 "
2,4-Dichlorophenol ND 0.33 "
Diethyl phthalate ND 0.33 "
2,4-Dimethylphenol ND 0.33 "
Dimethyl phthalate ND 0.33 "
Di-n-butyl phthalate ND 0.33 "
2,4-Dinitrophenol ND 0.33 "
4,6-Dinitro-2-methylphenol ND 0.33 "
2,4-Dinitrotoluene ND 0.33 "
2,6-Dinitrotoluene ND 0.33 "

Page 214 of 220 ends

Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/22/21 13:51
Town Center Northwest
Result Limit
Reporting
Units Level
Spike
Result
Source
%REC
%REC
Limits RPD
RPD
Analyte Limit Notes
Semivolatile Organic Compounds by EPA Method 8270C - Quality Control Sierra Analytical Labs, Inc.

Batch B1G1916 - EPA 3550B Solid Ext
Blank (B1G1916-BLK1) Prepared: 07/19/21 Analyzed: 07/20/21 Di-n-octyl phthalate ND 0.33 mg/kg
1,2-Diphenylhydrazine ND 0.33 "
Fluoranthene ND 0.33 "
Fluorene ND 0.33 "
Hexachlorobenzene ND 0.33 "
Hexachlorobutadiene ND 0.33 "
Hexachlorocyclopentadiene ND 0.33 "
Hexachloroethane ND 0.33 "
Indeno (1,2,3-cd) pyrene ND 0.33 "
Isophorone ND 0.33 "
2-Methylnaphthalene ND 0.33 "
2-Methylphenol ND 0.33 "
4-Methylphenol ND 0.33 "
Naphthalene ND 0.33 "
2-Nitroaniline ND 0.33 "
3-Nitroaniline ND 0.33 "
4-Nitroaniline ND 0.33 "
Nitrobenzene ND 0.33 "
2-Nitrophenol ND 0.33 "
4-Nitrophenol ND 0.33 "
N-Nitrosodimethylamine ND 0.33 "
Diphenylamine ND 0.33 "
N-Nitrosodi-n-propylamine ND 0.33 "
Pentachlorophenol ND 0.33 "
Phenanthrene ND 0.33 "
Phenol ND 0.33 "
Pyrene ND 0.33 "
1,2,4-Trichlorobenzene ND 0.33 "
2,4,5-Trichlorophenol ND 0.33 "
2,4,6-Trichlorophenol ND 0.33 "

Page 215 of 220 ends

Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/22/21 13:51
Town Center Northwest
Result Limit
Reporting
Units Level
Spike
Result
Source
%REC
%REC
Limits RPD
RPD
Analyte Limit Notes
Semivolatile Organic Compounds by EPA Method 8270C - Quality Control Sierra Analytical Labs, Inc.

Batch B1G1916 - EPA 3550B Solid Ext
Blank (B1G1916-BLK2) Prepared: 07/19/21 Analyzed: 07/20/21 Acenaphthene ND 0.33 mg/kg
Acenaphthylene ND 0.33 "
Anthracene ND 0.33 "
Benzidine ND 0.33 "
Benzo (a) anthracene ND 0.33 "
Benzo (b) fluoranthene ND 0.33 "
Benzo (k) fluoranthene ND 0.33 "
Benzo (a) pyrene ND 0.33 "
Benzo (g,h,i) perylene ND 0.33 "
Benzyl alcohol ND 0.33 "
Bis(2-chloroethyl)ether ND 0.33 "
Bis(2-chloroethoxy)methane ND 0.33 "
Bis(2-ethylhexyl)phthalate ND 0.33 "
Bis(2-chloroisopropyl)ether ND 0.33 "
4-Bromophenyl phenyl ether ND 0.33 "
Butyl benzyl phthalate ND 0.33 "
4-Chloroaniline ND 0.33 "
2-Chlorophenol ND 0.33 "
4-Chloro-3-methylphenol ND 0.33 "
2-Chloronaphthalene ND 0.33 "
4-Chlorophenyl phenyl ether ND 0.33 "
Chrysene ND 0.33 "
Dibenz (a,h) anthracene ND 0.33 "
Dibenzofuran ND 0.33 "
1,3-Dichlorobenzene ND 0.33 "
1,2-Dichlorobenzene ND 0.33 "
1,4-Dichlorobenzene ND 0.33 "
3,3´-Dichlorobenzidine ND 0.33 "
2,4-Dichlorophenol ND 0.33 "
Diethyl phthalate ND 0.33 "
2,4-Dimethylphenol ND 0.33 "
Dimethyl phthalate ND 0.33 "
Di-n-butyl phthalate ND 0.33 "
2,4-Dinitrophenol ND 0.33 "
4,6-Dinitro-2-methylphenol ND 0.33 "
2,4-Dinitrotoluene ND 0.33 "
2,6-Dinitrotoluene ND 0.33 "

Page 216 of 220 ends

Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/22/21 13:51
Town Center Northwest
Result Limit
Reporting
Units Level
Spike
Result
Source
%REC
%REC
Limits RPD
RPD
Analyte Limit Notes
Semivolatile Organic Compounds by EPA Method 8270C - Quality Control Sierra Analytical Labs, Inc.

Batch B1G1916 - EPA 3550B Solid Ext
Blank (B1G1916-BLK2) Prepared: 07/19/21 Analyzed: 07/20/21 Di-n-octyl phthalate ND 0.33 mg/kg
1,2-Diphenylhydrazine ND 0.33 "
Fluoranthene ND 0.33 "
Fluorene ND 0.33 "
Hexachlorobenzene ND 0.33 "
Hexachlorobutadiene ND 0.33 "
Hexachlorocyclopentadiene ND 0.33 "
Hexachloroethane ND 0.33 "
Indeno (1,2,3-cd) pyrene ND 0.33 "
Isophorone ND 0.33 "
2-Methylnaphthalene ND 0.33 "
2-Methylphenol ND 0.33 "
4-Methylphenol ND 0.33 "
Naphthalene ND 0.33 "
2-Nitroaniline ND 0.33 "
3-Nitroaniline ND 0.33 "
4-Nitroaniline ND 0.33 "
Nitrobenzene ND 0.33 "
2-Nitrophenol ND 0.33 "
4-Nitrophenol ND 0.33 "
N-Nitrosodimethylamine ND 0.33 "
Diphenylamine ND 0.33 "
N-Nitrosodi-n-propylamine ND 0.33 "
Pentachlorophenol ND 0.33 "
Phenanthrene ND 0.33 "
Phenol ND 0.33 "
Pyrene ND 0.33 "
1,2,4-Trichlorobenzene ND 0.33 "
2,4,5-Trichlorophenol ND 0.33 "
2,4,6-Trichlorophenol ND 0.33 "

Page 217 of 220 ends

Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/22/21 13:51
Town Center Northwest
Result Limit
Reporting
Units Level
Spike
Result
Source
%REC
%REC
Limits RPD
RPD
Analyte Limit Notes
Semivolatile Organic Compounds by EPA Method 8270C - Quality Control Sierra Analytical Labs, Inc.

Batch B1G1916 - EPA 3550B Solid Ext
LCS (B1G1916-BS1) Prepared: 07/19/21 Analyzed: 07/20/21 Acenaphthene 0.848 0.33 mg/kg 1.00 84.8 47-145
2-Chlorophenol 1.85 0.33 " 2.00 92.3 23-134
4-Chloro-3-methylphenol 1.96 0.33 " 2.00 98.2 22-147
1,4-Dichlorobenzene 0.815 0.33 " 1.00 81.5 20-124
2,4-Dinitrotoluene 0.479 0.33 " 1.00 47.9 39-139
4-Nitrophenol 0.664 0.33 " 2.00 33.2 0-132
N-Nitrosodi-n-propylamine 0.797 0.33 " 1.00 79.7 0-230
Pentachlorophenol 0.379 0.33 " 2.00 19.0 14-176
Phenol 1.78 0.33 " 2.00 89.0 5-112
Pyrene 0.709 0.33 " 1.00 70.9 52-115
1,2,4-Trichlorobenzene 0.729 0.33 " 1.00 72.9 44-142
LCS (B1G1916-BS2) Prepared: 07/19/21 Analyzed: 07/20/21 Acenaphthene 0.844 0.33 mg/kg 1.00 84.4 47-145
2-Chlorophenol 1.81 0.33 " 2.00 90.6 23-134
4-Chloro-3-methylphenol 2.16 0.33 " 2.00 108 22-147
1,4-Dichlorobenzene 0.796 0.33 " 1.00 79.6 20-124
2,4-Dinitrotoluene 0.523 0.33 " 1.00 52.3 39-139
4-Nitrophenol 0.642 0.33 " 2.00 32.1 0-132
N-Nitrosodi-n-propylamine 0.711 0.33 " 1.00 71.1 0-230
Pentachlorophenol 0.351 0.33 " 2.00 17.6 14-176
Phenol 1.65 0.33 " 2.00 82.6 5-112
Pyrene 0.694 0.33 " 1.00 69.4 52-115
1,2,4-Trichlorobenzene 0.615 0.33 " 1.00 61.5 44-142
Matrix Spike (B1G1916-MS1) Source: 2107188-19 Prepared: 07/19/21 Analyzed: 07/20/21 Acenaphthene 0.919 0.33 mg/kg 1.00 ND 91.9 47-145
2-Chlorophenol 1.82 0.33 " 2.00 ND 91.2 23-134
4-Chloro-3-methylphenol 1.84 0.33 " 2.00 ND 91.9 22-147 1,4-Dichlorobenzene 0.880 0.33 " 1.00 ND 88.0 20-124
2,4-Dinitrotoluene 0.899 0.33 " 1.00 ND 89.9 39-139
4-Nitrophenol 0.634 0.33 " 2.00 ND 31.7 0-132
N-Nitrosodi-n-propylamine 0.834 0.33 " 1.00 ND 83.4 0-230 Pentachlorophenol 0.413 0.33 " 2.00 ND 20.6 14-176
Phenol 1.68 0.33 " 2.00 ND 84.2 5-112
Pyrene 0.866 0.33 " 1.00 ND 86.6 52-115
1,2,4-Trichlorobenzene 0.810 0.33 " 1.00 ND 81.0 44-142

Page 218 of 220 ends

Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/22/21 13:51
Town Center Northwest
Result Limit
Reporting
Units Level
Spike
Result
Source
%REC
%REC
Limits RPD
RPD
Analyte Limit Notes
Semivolatile Organic Compounds by EPA Method 8270C - Quality Control Sierra Analytical Labs, Inc.

Batch B1G1916 - EPA 3550B Solid Ext
Matrix Spike (B1G1916-MS2) Source: 2107188-30 Prepared: 07/19/21 Analyzed: 07/20/21 Acenaphthene 0.919 0.33 mg/kg 1.00 ND 91.9 47-145
2-Chlorophenol 1.82 0.33 " 2.00 ND 91.2 23-134
4-Chloro-3-methylphenol 1.84 0.33 " 2.00 ND 91.9 22-147 1,4-Dichlorobenzene 0.880 0.33 " 1.00 ND 88.0 20-124
2,4-Dinitrotoluene 0.544 0.33 " 1.00 ND 54.4 39-139
4-Nitrophenol 0.634 0.33 " 2.00 ND 31.7 0-132
N-Nitrosodi-n-propylamine 0.834 0.33 " 1.00 ND 83.4 0-230 Pentachlorophenol 0.413 0.33 " 2.00 ND 20.6 14-176
Phenol 1.68 0.33 " 2.00 ND 84.2 5-112
Pyrene 0.866 0.33 " 1.00 ND 86.6 52-115
1,2,4-Trichlorobenzene 0.810 0.33 " 1.00 ND 81.0 44-142 Matrix Spike Dup (B1G1916-MSD1) Source: 2107188-19 Prepared: 07/19/21 Analyzed: 07/20/21 Acenaphthene 0.968 0.33 mg/kg 1.00 ND 96.8 47-145 5.19 30 2-Chlorophenol 1.85 0.33 " 2.00 ND 92.3 23-134 1.25 30
4-Chloro-3-methylphenol 2.06 0.33 " 2.00 ND 103 22-147 11.2 30 1,4-Dichlorobenzene 0.923 0.33 " 1.00 ND 92.3 20-124 4.77 30 2,4-Dinitrotoluene 0.920 0.33 " 1.00 ND 92.0 39-139 2.31 30 4-Nitrophenol 0.629 0.33 " 2.00 ND 31.4 0-132 0.792 30
N-Nitrosodi-n-propylamine 0.847 0.33 " 1.00 ND 84.7 0-230 1.55 30 Pentachlorophenol 0.458 0.33 " 2.00 ND 22.9 14-176 10.3 30 Phenol 1.67 0.33 " 2.00 ND 83.4 5-112 0.955 30
Pyrene 0.995 0.33 " 1.00 ND 99.5 52-115 13.9 30
1,2,4-Trichlorobenzene 0.710 0.33 " 1.00 ND 71.0 44-142 13.2 30 Matrix Spike Dup (B1G1916-MSD2) Source: 2107188-30 Prepared: 07/19/21 Analyzed: 07/20/21 Acenaphthene 1.00 0.33 mg/kg 1.00 ND 100 47-145 8.44 30 2-Chlorophenol 1.92 0.33 " 2.00 ND 96.0 23-134 5.13 30
4-Chloro-3-methylphenol 1.99 0.33 " 2.00 ND 99.4 22-147 7.79 30 1,4-Dichlorobenzene 0.920 0.33 " 1.00 ND 92.0 20-124 4.44 30 2,4-Dinitrotoluene 0.594 0.33 " 1.00 ND 59.4 39-139 8.79 30 4-Nitrophenol 0.650 0.33 " 2.00 ND 32.5 0-132 2.49 30
N-Nitrosodi-n-propylamine 0.899 0.33 " 1.00 ND 89.9 0-230 7.50 30 Pentachlorophenol 0.489 0.33 " 2.00 ND 24.4 14-176 16.9 30 Phenol 1.72 0.33 " 2.00 ND 86.2 5-112 2.35 30
Pyrene 0.679 0.33 " 1.00 ND 67.9 52-115 24.2 30
1,2,4-Trichlorobenzene 0.723 0.33 " 1.00 ND 72.3 44-142 11.4 30

Page 219 of 220 ends

Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/22/21 13:51
Town Center Northwest
Notes and Definitions
S-07 Surrogate recovery outside of control limits due to coelution with high levels of petroleum hydrocarbons.

S-03 Surrogate diluted out.

QM-07 The spike recovery was outside acceptance limits for the MS and/or MSD. The batch was accepted based on acceptable LCS recovery.

Sample results reported on a dry weight basis
RPD Relative Percent Difference
dry
NR Not Reported
ND Analyte NOT DETECTED at or above the reporting limit DET Analyte DETECTED

Page 220 of 220 ends

APPENDIX B
Jones Environmental Inc.

Soil Vapor Analytical Results
July 27 & 28, 2021
Client: Report date: 7/27/2021
Client Address: Jones Ref. No.: E-1172
Attn: Date Sampled: 7/27/2021
Date Received: 7/27/2021
Project: Date Analyzed: 7/27/2021
Project Address: Physical State: Soil Gas

JONES ENVIRONMENTAL LABORATORY RESULTS

ANALYSES REQUESTED

1. EPA 8260B – Volatile Organics by GC/MS + Oxygenates/Gasoline Range Organics Mearns Consulting Group
738 Ashland Avenue,
Santa Monica CA 90405
Susan L Mearns PhD
Town Center Northwest
2690 Walnut Ave
Signal Hill, CA
Sampling – Soil Gas samples were collected in glass gas-tight syringes equipped with Teflon plungers.

A tracer gas mixture of n-pentane, n-hexane, and n-heptane was placed at the tubing-surface interface before sampling. These compounds were analyzed during the 8260B analytical run to determine if there were surface leaks into the subsurface due to improper installation of the probe. No tracer was detected in any of the samples reported herein.

The sampling rate was approximately 200 cc/min, except when noted differently on the chain of custody record, using a glass gas-tight syringe. Purging was completed using a pump set at approximately 200 cc/min, except when noted differently on the chain of custody record. A default of 3 purge volumes was used as recommended by July 2015 DTSC/RWQCB guidance documents.

Prior to purging and sampling of soil gas at each point, a shut-in test was conducted to check for leaks in the above ground fittings. The shut-in test was performed on the above ground apparatus by evacuating the line to a vacuum of 100 inches of water, sealing the entire system and watching the vacuum for at least one minute. A vacuum gauge attached in parallel to the apparatus measured the vacuum. If there was any observable loss of vacuum, the fittings were adjusted as needed until the vacuum did not change noticeably. The soil gas sample was then taken.

No flow conditions occur when a sampling rate greater than 10 mL/min cannot be maintained without applying a vacuum greater than 100 inches of water to the sampling train. The sampling train is left at a vacuum for no less than three minutes. If the vacuum does not subside appreciably after three minutes, the sample location is determined to be a no flow sample.

Analytical – Soil Gas samples were analyzed using EPA Method 8260 that includes extra compounds required by DTSC/RWQCB (such as Freon 113). Instrument Continuing Calibration Verification, QC Reference Standards, Instrument Blanks and Sampling Blanks were analyzed every 12 hours as prescribed by the method. In addition, a Laboratory Control Sample (LCS) and Laboratory Control Sample Duplicate (LCSD) were analyzed with each batch of Soil Gas samples. A duplicate/replicate sample was analyzed each day of the sampling activity. All samples were injected into the GC/MS system within 30 minutes of collection.

Approval:

Annalise O’Toole
Mobile Lab Manager

Page 1 of 14 ends

Client: Report date: 7/27/2021
Client Address: Jones Ref. No.: E-1172
Attn: Date Sampled: 7/27/2021
Date Received: 7/27/2021
Project: Date Analyzed: 7/27/2021
Project Address: Physical State: Soil Gas
Sample ID: SV1-5' SV1-15' SV2-5' SV2-15' SV2-15'
REP
Jones ID: E-1172-01 E-1172-02 E-1172-03 E-1172-04 E-1172-05 Analytes:

Benzene ND 13 ND ND ND 8 μg/m3
Bromobenzene ND ND ND ND ND 8 μg/m3
Bromodichloromethane ND ND ND ND ND 8 μg/m3
Bromoform ND ND ND ND ND 8 μg/m3
n-Butylbenzene ND ND ND ND ND 12 μg/m3
sec-Butylbenzene ND ND ND ND ND 12 μg/m3
tert-Butylbenzene ND ND ND ND ND 12 μg/m3
Carbon tetrachloride ND ND ND ND ND 8 μg/m3
Chlorobenzene ND ND ND ND ND 8 μg/m3
Chloroform ND ND ND ND ND 8 μg/m3
2-Chlorotoluene ND ND ND ND ND 12 μg/m3
4-Chlorotoluene ND ND ND ND ND 12 μg/m3
Dibromochloromethane ND ND ND ND ND 8 μg/m3
1,2-Dibromo-3-chloropropane ND ND ND ND ND 8 μg/m3
1,2-Dibromoethane (EDB) ND ND ND ND ND 8 μg/m3
Dibromomethane ND ND ND ND ND 8 μg/m3
1,2- Dichlorobenzene ND ND ND ND ND 16 μg/m3
1,3-Dichlorobenzene ND ND ND ND ND 16 μg/m3
1,4-Dichlorobenzene ND ND ND ND ND 16 μg/m3
Dichlorodifluoromethane ND ND ND ND ND 32 μg/m3
1,1-Dichloroethane ND ND ND ND ND 8 μg/m3
1,2-Dichloroethane ND ND ND ND ND 8 μg/m3
1,1-Dichloroethene ND ND ND ND ND 8 μg/m3
cis-1,2-Dichloroethene ND ND ND ND ND 8 μg/m3
trans-1,2-Dichloroethene ND ND ND ND ND 8 μg/m3
1,2-Dichloropropane ND ND ND ND ND 8 μg/m3
1,3-Dichloropropane ND ND ND ND ND 8 μg/m3
2,2-Dichloropropane ND ND ND ND ND 16 μg/m3
1,1-Dichloropropene ND ND ND ND ND 10 μg/m3

JONES ENVIRONMENTAL LABORATORY RESULTS
738 Ashland Avenue,
Susan L Mearns PhD
Mearns Consulting Group
Santa Monica CA 90405
Town Center Northwest
Reporting Limit
EPA 8260B – Volatile Organics by GC/MS + Oxygenates/Gasoline Range Organics Units
2690 Walnut Ave
Signal Hill, CA

Page 2 of 14 ends

Sample ID: SV1-5' SV1-15' SV2-5' SV2-15' SV2-15'
REP
Jones ID: E-1172-01 E-1172-02 E-1172-03 E-1172-04 E-1172-05 Analytes:
cis-1,3-Dichloropropene ND ND ND ND ND 8 μg/m3
trans-1,3-Dichloropropene ND ND ND ND ND 8 μg/m3
Ethylbenzene ND ND ND ND ND 8 μg/m3
Freon 113 ND ND ND ND ND 16 μg/m3
Hexachlorobutadiene ND ND ND ND ND 24 μg/m3
Isopropylbenzene ND 57 ND ND ND 8 μg/m3
4-Isopropyltoluene ND 321 ND ND ND 8 μg/m3
Methylene chloride ND 20 ND 17 26 8 μg/m3
Naphthalene ND ND ND ND ND 40 μg/m3
n-Propylbenzene ND ND ND ND ND 8 μg/m3
Styrene ND ND ND ND ND 8 μg/m3
1,1,1,2-Tetrachloroethane ND ND ND ND ND 8 μg/m3
1,1,2,2-Tetrachloroethane ND ND ND ND ND 16 μg/m3
Tetrachloroethene ND ND ND ND ND 8 μg/m3
Toluene ND 16 ND ND ND 8 μg/m3
1,2,3-Trichlorobenzene ND ND ND ND ND 16 μg/m3
1,2,4-Trichlorobenzene ND ND ND ND ND 16 μg/m3
1,1,1-Trichloroethane ND ND ND ND ND 8 μg/m3
1,1,2-Trichloroethane ND ND ND ND ND 8 μg/m3
Trichloroethene ND ND ND ND ND 8 μg/m3
Trichlorofluoromethane ND ND ND ND ND 32 μg/m3
1,2,3-Trichloropropane ND ND ND ND ND 8 μg/m3
1,2,4-Trimethylbenzene ND ND ND ND ND 8 μg/m3
1,3,5-Trimethylbenzene ND ND ND ND ND 8 μg/m3
Vinyl chloride ND ND ND ND ND 8 μg/m3
m,p-Xylene ND ND ND ND ND 16 μg/m3
o-Xylene ND ND ND ND ND 8 μg/m3
MTBE ND ND ND ND ND 40 μg/m3
Ethyl-tert-butylether ND ND ND ND ND 40 μg/m3
Di-isopropylether ND ND ND ND ND 40 μg/m3
tert-amylmethylether ND ND ND ND ND 40 μg/m3
tert-Butylalcohol ND ND ND ND ND 400 μg/m3
Gasoline Range Organics (C4-C12) ND 25000 ND ND ND 2000 μg/m3 Tracer:
n-Pentane ND ND ND ND ND 80 μg/m3
n-Hexane ND ND ND ND ND 80 μg/m3
n-Heptane ND ND ND ND ND 80 μg/m3
Dilution Factor 1 1 1 1 1
Surrogate Recoveries:

Dibromofluoromethane 104% 101% 102% 101% 100%
Toluene-d₈ 94% 95% 94% 92% 93%
4-Bromofluorobenzene 94% 97% 94% 92% 92%
Batch ID: E3-072721-
01 E3-072721-
01 E3-072721-
01 E3-072721-
01 E3-072721-
01 ND = Value below reporting limit
60 - 140
60 - 140
Reporting Limit Units
60 - 140
QC Limits
EPA 8260B – Volatile Organics by GC/MS + Oxygenates/Gasoline Range Organics

JONES ENVIRONMENTAL LABORATORY RESULTS

Page 3 of 14 ends

Client: Report date: 7/27/2021
Client Address: Jones Ref. No.: E-1172
Attn: Date Sampled: 7/27/2021
Date Received: 7/27/2021
Project: Date Analyzed: 7/27/2021
Project Address: Physical State: Soil Gas
Sample ID: SV3-5' SV3-15' SV4-5' SV4-15' SV5-5'
Jones ID: E-1172-06 E-1172-07 E-1172-08 E-1172-09 E-1172-10 Analytes:

Benzene ND ND ND ND ND 8 μg/m3
Bromobenzene ND ND ND ND ND 8 μg/m3
Bromodichloromethane ND ND ND ND ND 8 μg/m3
Bromoform ND ND ND ND ND 8 μg/m3
n-Butylbenzene ND ND ND ND ND 12 μg/m3
sec-Butylbenzene ND ND ND ND ND 12 μg/m3
tert-Butylbenzene ND ND ND ND ND 12 μg/m3
Carbon tetrachloride ND ND ND ND ND 8 μg/m3
Chlorobenzene ND ND ND ND ND 8 μg/m3
Chloroform ND ND ND ND ND 8 μg/m3
2-Chlorotoluene ND ND ND ND ND 12 μg/m3
4-Chlorotoluene ND ND ND ND ND 12 μg/m3
Dibromochloromethane ND ND ND ND ND 8 μg/m3
1,2-Dibromo-3-chloropropane ND ND ND ND ND 8 μg/m3
1,2-Dibromoethane (EDB) ND ND ND ND ND 8 μg/m3
Dibromomethane ND ND ND ND ND 8 μg/m3
1,2- Dichlorobenzene ND ND ND ND ND 16 μg/m3
1,3-Dichlorobenzene ND ND ND ND ND 16 μg/m3
1,4-Dichlorobenzene ND ND ND ND ND 16 μg/m3
Dichlorodifluoromethane ND ND ND ND ND 32 μg/m3
1,1-Dichloroethane ND ND ND ND ND 8 μg/m3
1,2-Dichloroethane ND ND ND ND ND 8 μg/m3
1,1-Dichloroethene ND ND ND ND ND 8 μg/m3
cis-1,2-Dichloroethene ND ND ND ND ND 8 μg/m3
trans-1,2-Dichloroethene ND ND ND ND ND 8 μg/m3
1,2-Dichloropropane ND ND ND ND ND 8 μg/m3
1,3-Dichloropropane ND ND ND ND ND 8 μg/m3
2,2-Dichloropropane ND ND ND ND ND 16 μg/m3
1,1-Dichloropropene ND ND ND ND ND 10 μg/m3
Susan L Mearns PhD
Town Center Northwest
2690 Walnut Ave
Signal Hill, CA
EPA 8260B – Volatile Organics by GC/MS + Oxygenates/Gasoline Range Organics Reporting Limit Units

JONES ENVIRONMENTAL LABORATORY RESULTS
Mearns Consulting Group
738 Ashland Avenue,
Santa Monica CA 90405

Page 4 of 14 ends

Sample ID: SV3-5' SV3-15' SV4-5' SV4-15' SV5-5'
Jones ID: E-1172-06 E-1172-07 E-1172-08 E-1172-09 E-1172-10 Analytes:
cis-1,3-Dichloropropene ND ND ND ND ND 8 μg/m3
trans-1,3-Dichloropropene ND ND ND ND ND 8 μg/m3
Ethylbenzene ND ND ND ND ND 8 μg/m3
Freon 113 ND ND ND ND ND 16 μg/m3
Hexachlorobutadiene ND ND ND ND ND 24 μg/m3
Isopropylbenzene ND ND ND ND ND 8 μg/m3
4-Isopropyltoluene ND ND ND ND ND 8 μg/m3
Methylene chloride ND 8 ND ND ND 8 μg/m3
Naphthalene ND ND ND ND ND 40 μg/m3
n-Propylbenzene ND ND ND ND ND 8 μg/m3
Styrene ND ND ND ND ND 8 μg/m3
1,1,1,2-Tetrachloroethane ND ND ND ND ND 8 μg/m3
1,1,2,2-Tetrachloroethane ND ND ND ND ND 16 μg/m3
Tetrachloroethene 18 17 22 12 ND 8 μg/m3
Toluene ND ND ND ND ND 8 μg/m3
1,2,3-Trichlorobenzene ND ND ND ND ND 16 μg/m3
1,2,4-Trichlorobenzene ND ND ND ND ND 16 μg/m3
1,1,1-Trichloroethane ND ND ND ND ND 8 μg/m3
1,1,2-Trichloroethane ND ND ND ND ND 8 μg/m3
Trichloroethene ND ND ND ND ND 8 μg/m3
Trichlorofluoromethane ND ND ND ND ND 32 μg/m3
1,2,3-Trichloropropane ND ND ND ND ND 8 μg/m3
1,2,4-Trimethylbenzene ND ND ND ND ND 8 μg/m3
1,3,5-Trimethylbenzene ND ND ND ND ND 8 μg/m3
Vinyl chloride ND ND ND ND ND 8 μg/m3
m,p-Xylene ND ND ND ND ND 16 μg/m3
o-Xylene ND ND ND ND ND 8 μg/m3
MTBE ND ND ND ND ND 40 μg/m3
Ethyl-tert-butylether ND ND ND ND ND 40 μg/m3
Di-isopropylether ND ND ND ND ND 40 μg/m3
tert-amylmethylether ND ND ND ND ND 40 μg/m3
tert-Butylalcohol ND ND ND ND ND 400 μg/m3
Gasoline Range Organics (C4-C12) ND ND ND ND ND 2000 μg/m3 Tracer:
n-Pentane ND ND ND ND ND 80 μg/m3
n-Hexane ND ND ND ND ND 80 μg/m3
n-Heptane ND ND ND ND ND 80 μg/m3
Dilution Factor 1 1 1 1 1
Surrogate Recoveries:

Dibromofluoromethane 104% 102% 104% 100% 106%
Toluene-d₈ 93% 94% 93% 92% 93%
4-Bromofluorobenzene 93% 92% 94% 93% 92%
Batch ID: E3-072721-
01 E3-072721-
01 E3-072721-
01 E3-072721-
01 E3-072721-
01 ND = Value below reporting limit
60 - 140
60 - 140
60 - 140

JONES ENVIRONMENTAL LABORATORY RESULTS
EPA 8260B – Volatile Organics by GC/MS + Oxygenates/Gasoline Range Organics Reporting Limit Units
QC Limits

Page 5 of 14 ends

Client: Report date: 7/27/2021
Client Address: Jones Ref. No.: E-1172
Attn: Date Sampled: 7/27/2021
Date Received: 7/27/2021
Project: Date Analyzed: 7/27/2021
Project Address: Physical State: Soil Gas
Sample ID: SV5-15' SV6-5' SV6-15' SV7-5' SV7-15'
Jones ID: E-1172-11 E-1172-12 E-1172-13 E-1172-14 E-1172-15 Analytes:

Benzene ND ND 243 ND 8850 8 μg/m3
Bromobenzene ND ND ND ND ND 8 μg/m3
Bromodichloromethane ND ND ND ND ND 8 μg/m3
Bromoform ND ND ND ND ND 8 μg/m3
n-Butylbenzene ND ND ND ND ND 12 μg/m3
sec-Butylbenzene ND ND ND ND ND 12 μg/m3
tert-Butylbenzene ND ND ND ND ND 12 μg/m3
Carbon tetrachloride ND ND ND ND ND 8 μg/m3
Chlorobenzene ND ND ND ND ND 8 μg/m3
Chloroform ND ND ND ND ND 8 μg/m3
2-Chlorotoluene ND ND ND ND ND 12 μg/m3
4-Chlorotoluene ND ND ND ND ND 12 μg/m3
Dibromochloromethane ND ND ND ND ND 8 μg/m3
1,2-Dibromo-3-chloropropane ND ND ND ND ND 8 μg/m3
1,2-Dibromoethane (EDB) ND ND ND ND ND 8 μg/m3
Dibromomethane ND ND ND ND ND 8 μg/m3
1,2- Dichlorobenzene ND ND ND ND ND 16 μg/m3
1,3-Dichlorobenzene ND ND ND ND ND 16 μg/m3
1,4-Dichlorobenzene ND ND ND ND ND 16 μg/m3
Dichlorodifluoromethane ND ND ND ND ND 32 μg/m3
1,1-Dichloroethane ND ND ND ND ND 8 μg/m3
1,2-Dichloroethane ND ND ND ND ND 8 μg/m3
1,1-Dichloroethene ND ND ND ND ND 8 μg/m3
cis-1,2-Dichloroethene ND ND ND ND ND 8 μg/m3
trans-1,2-Dichloroethene ND ND ND ND ND 8 μg/m3
1,2-Dichloropropane ND ND ND ND ND 8 μg/m3
1,3-Dichloropropane ND ND ND ND ND 8 μg/m3
2,2-Dichloropropane ND ND ND ND ND 16 μg/m3
1,1-Dichloropropene ND ND ND ND ND 10 μg/m3
Susan L Mearns PhD
Town Center Northwest
2690 Walnut Ave
Signal Hill, CA
EPA 8260B – Volatile Organics by GC/MS + Oxygenates/Gasoline Range Organics Reporting Limit Units

JONES ENVIRONMENTAL LABORATORY RESULTS
Mearns Consulting Group
738 Ashland Avenue,
Santa Monica CA 90405

Page 6 of 14 ends

Sample ID: SV5-15' SV6-5' SV6-15' SV7-5' SV7-15'
Jones ID: E-1172-11 E-1172-12 E-1172-13 E-1172-14 E-1172-15 Analytes:
cis-1,3-Dichloropropene ND ND ND ND ND 8 μg/m3
trans-1,3-Dichloropropene ND ND ND ND ND 8 μg/m3
Ethylbenzene ND ND ND ND ND 8 μg/m3
Freon 113 ND ND ND ND ND 16 μg/m3
Hexachlorobutadiene ND ND ND ND ND 24 μg/m3
Isopropylbenzene ND ND ND ND ND 8 μg/m3
4-Isopropyltoluene ND ND ND ND ND 8 μg/m3
Methylene chloride 9 ND ND ND ND 8 μg/m3
Naphthalene ND ND ND ND ND 40 μg/m3
n-Propylbenzene ND ND ND ND ND 8 μg/m3
Styrene ND ND ND ND ND 8 μg/m3
1,1,1,2-Tetrachloroethane ND ND ND ND ND 8 μg/m3
1,1,2,2-Tetrachloroethane ND ND ND ND ND 16 μg/m3
Tetrachloroethene ND 17 8 ND ND 8 μg/m3
Toluene ND ND ND ND 4210 8 μg/m3
1,2,3-Trichlorobenzene ND ND ND ND ND 16 μg/m3
1,2,4-Trichlorobenzene ND ND ND ND ND 16 μg/m3
1,1,1-Trichloroethane ND ND ND ND ND 8 μg/m3
1,1,2-Trichloroethane ND ND ND ND ND 8 μg/m3
Trichloroethene ND ND ND ND ND 8 μg/m3
Trichlorofluoromethane ND ND ND ND ND 32 μg/m3
1,2,3-Trichloropropane ND ND ND ND ND 8 μg/m3
1,2,4-Trimethylbenzene ND ND ND ND ND 8 μg/m3
1,3,5-Trimethylbenzene ND ND ND ND ND 8 μg/m3
Vinyl chloride ND ND ND ND ND 8 μg/m3
m,p-Xylene ND ND ND ND 799 16 μg/m3
o-Xylene ND ND ND ND 441 8 μg/m3
MTBE ND ND ND ND ND 40 μg/m3
Ethyl-tert-butylether ND ND ND ND ND 40 μg/m3
Di-isopropylether ND ND ND ND ND 40 μg/m3
tert-amylmethylether ND ND ND ND ND 40 μg/m3
tert-Butylalcohol ND ND ND ND ND 400 μg/m3
Gasoline Range Organics (C4-C12) ND ND 317000 ND 46300000 2000 μg/m3 Tracer:
n-Pentane ND ND ND ND ND 80 μg/m3
n-Hexane ND ND ND ND ND 80 μg/m3
n-Heptane ND ND ND ND ND 80 μg/m3
Dilution Factor 1 1 1 1 30
Surrogate Recoveries:

Dibromofluoromethane 102% 100% 97% 100% 97%
Toluene-d₈ 95% 92% 101% 93% 97%
4-Bromofluorobenzene 94% 94% 91% 93% 96%
Batch ID: E3-072721-
01 E3-072721-
01 E3-072721-
01 E3-072721-
01 E3-072721-
01 ND = Value below reporting limit
60 - 140
60 - 140
60 - 140

JONES ENVIRONMENTAL LABORATORY RESULTS
EPA 8260B – Volatile Organics by GC/MS + Oxygenates/Gasoline Range Organics Reporting Limit Units
QC Limits

Page 7 of 14 ends

Client: Report date: 7/27/2021
Client Address: Jones Ref. No.: E-1172
Attn: Date Sampled: 7/27/2021
Date Received: 7/27/2021
Project: Date Analyzed: 7/27/2021
Project Address: Physical State: Soil Gas
Sample ID: SV8-5' SV8-15' SV9-5' SV7-15' DIL
Jones ID: E-1172-16 E-1172-17 E-1172-18 -
Analytes:

Benzene 20 ND ND ND ND 8 μg/m3
Bromobenzene ND ND ND ND ND 8 μg/m3
Bromodichloromethane ND ND ND ND ND 8 μg/m3
Bromoform ND ND ND ND ND 8 μg/m3
n-Butylbenzene ND ND ND ND ND 12 μg/m3
sec-Butylbenzene ND ND ND ND ND 12 μg/m3
tert-Butylbenzene ND ND ND ND ND 12 μg/m3
Carbon tetrachloride ND ND ND ND ND 8 μg/m3
Chlorobenzene ND ND ND ND ND 8 μg/m3
Chloroform ND ND ND ND ND 8 μg/m3
2-Chlorotoluene ND ND ND ND ND 12 μg/m3
4-Chlorotoluene ND ND ND ND ND 12 μg/m3
Dibromochloromethane ND ND ND ND ND 8 μg/m3
1,2-Dibromo-3-chloropropane ND ND ND ND ND 8 μg/m3
1,2-Dibromoethane (EDB) ND ND ND ND ND 8 μg/m3
Dibromomethane ND ND ND ND ND 8 μg/m3
1,2- Dichlorobenzene ND ND ND ND ND 16 μg/m3
1,3-Dichlorobenzene ND ND ND ND ND 16 μg/m3
1,4-Dichlorobenzene ND ND ND ND ND 16 μg/m3
Dichlorodifluoromethane ND ND ND ND ND 32 μg/m3
1,1-Dichloroethane ND ND ND ND ND 8 μg/m3
1,2-Dichloroethane ND ND ND ND ND 8 μg/m3
1,1-Dichloroethene ND ND ND ND ND 8 μg/m3
cis-1,2-Dichloroethene ND ND ND ND ND 8 μg/m3
trans-1,2-Dichloroethene ND ND ND ND ND 8 μg/m3
1,2-Dichloropropane ND ND ND ND ND 8 μg/m3
1,3-Dichloropropane ND ND ND ND ND 8 μg/m3
2,2-Dichloropropane ND ND ND ND ND 16 μg/m3
1,1-Dichloropropene ND ND ND ND ND 10 μg/m3
Reporting Limit Units
Susan L Mearns PhD
Town Center Northwest
2690 Walnut Ave
Signal Hill, CA
EPA 8260B – Volatile Organics by GC/MS + Oxygenates/Gasoline Range Organics

JONES ENVIRONMENTAL LABORATORY RESULTS
Mearns Consulting Group
738 Ashland Avenue,
Santa Monica CA 90405

Page 8 of 14 ends

Sample ID: SV8-5' SV8-15' SV9-5' SV7-15' DIL
Jones ID: E-1172-16 E-1172-17 E-1172-18 -
Analytes:
cis-1,3-Dichloropropene ND ND ND ND ND 8 μg/m3
trans-1,3-Dichloropropene ND ND ND ND ND 8 μg/m3
Ethylbenzene ND ND ND ND ND 8 μg/m3
Freon 113 ND ND ND ND ND 16 μg/m3
Hexachlorobutadiene ND ND ND ND ND 24 μg/m3
Isopropylbenzene ND ND ND ND ND 8 μg/m3
4-Isopropyltoluene ND ND ND ND ND 8 μg/m3
Methylene chloride ND ND ND ND ND 8 μg/m3
Naphthalene ND ND ND ND ND 40 μg/m3
n-Propylbenzene ND ND ND ND ND 8 μg/m3
Styrene ND ND ND ND ND 8 μg/m3
1,1,1,2-Tetrachloroethane ND ND ND ND ND 8 μg/m3
1,1,2,2-Tetrachloroethane ND ND ND ND ND 16 μg/m3
Tetrachloroethene 23 ND ND ND ND 8 μg/m3
Toluene 15 ND ND ND ND 8 μg/m3
1,2,3-Trichlorobenzene ND ND ND ND ND 16 μg/m3
1,2,4-Trichlorobenzene ND ND ND ND ND 16 μg/m3
1,1,1-Trichloroethane ND ND ND ND ND 8 μg/m3
1,1,2-Trichloroethane ND ND ND ND ND 8 μg/m3
Trichloroethene ND ND ND ND ND 8 μg/m3
Trichlorofluoromethane ND ND ND ND ND 32 μg/m3
1,2,3-Trichloropropane ND ND ND ND ND 8 μg/m3
1,2,4-Trimethylbenzene ND ND ND ND ND 8 μg/m3
1,3,5-Trimethylbenzene ND ND ND ND ND 8 μg/m3
Vinyl chloride ND ND ND ND ND 8 μg/m3
m,p-Xylene ND ND ND ND ND 16 μg/m3
o-Xylene ND ND ND ND ND 8 μg/m3
MTBE ND ND ND ND ND 40 μg/m3
Ethyl-tert-butylether ND ND ND ND ND 40 μg/m3
Di-isopropylether ND ND ND ND ND 40 μg/m3
tert-amylmethylether ND ND ND ND ND 40 μg/m3
tert-Butylalcohol ND ND ND ND ND 400 μg/m3
Gasoline Range Organics (C4-C12) ND ND ND ND ND 2000 μg/m3 Tracer:
n-Pentane ND ND ND ND ND 80 μg/m3
n-Hexane ND ND ND ND ND 80 μg/m3
n-Heptane ND ND ND ND ND 80 μg/m3
Dilution Factor 1 1 1 1 1
Surrogate Recoveries:

Dibromofluoromethane 95% 96% 95%
Toluene-d₈ 94% 92% 93%
4-Bromofluorobenzene 95% 96% 94%
Batch ID: E3-072721-
01 E3-072721-
01 E3-072721-
01 60 - 140
ND = Value below reporting limit
EPA 8260B – Volatile Organics by GC/MS + Oxygenates/Gasoline Range Organics Reporting Limit Units
QC Limits
60 - 140
60 - 140

JONES ENVIRONMENTAL LABORATORY RESULTS

Page 9 of 14 ends

SAMPLING
BLANK
METHOD
BLANK

SAMPLING
BLANK
Jones ID: 072721-
E3MB1
072721-
E3SB1
072721-
E3MB1
072721-
E3SB1
Analytes:

Benzene ND ND ND ND 8 μg/m3
Bromobenzene ND ND ND ND 8 μg/m3
Bromodichloromethane ND ND ND ND 8 μg/m3
Bromoform ND ND ND ND 8 μg/m3
n-Butylbenzene ND ND ND ND 12 μg/m3
sec-Butylbenzene ND ND ND ND 12 μg/m3
tert-Butylbenzene ND ND ND ND 12 μg/m3
Carbon tetrachloride ND ND ND ND 8 μg/m3
Chlorobenzene ND ND ND ND 8 μg/m3
Chloroform ND ND ND ND 8 μg/m3
2-Chlorotoluene ND ND ND ND 12 μg/m3
4-Chlorotoluene ND ND ND ND 12 μg/m3
Dibromochloromethane ND ND ND ND 8 μg/m3
1,2-Dibromo-3-chloropropane ND ND ND ND 8 μg/m3
1,2-Dibromoethane (EDB) ND ND ND ND 8 μg/m3
Dibromomethane ND ND ND ND 8 μg/m3
1,2- Dichlorobenzene ND ND ND ND 16 μg/m3
1,3-Dichlorobenzene ND ND ND ND 16 μg/m3
1,4-Dichlorobenzene ND ND ND ND 16 μg/m3
Dichlorodifluoromethane ND ND ND ND 32 μg/m3
1,1-Dichloroethane ND ND ND ND 8 μg/m3
1,2-Dichloroethane ND ND ND ND 8 μg/m3
1,1-Dichloroethene ND ND ND ND 8 μg/m3
cis-1,2-Dichloroethene ND ND ND ND 8 μg/m3
trans-1,2-Dichloroethene ND ND ND ND 8 μg/m3
1,2-Dichloropropane ND ND ND ND 8 μg/m3
1,3-Dichloropropane ND ND ND ND 8 μg/m3
2,2-Dichloropropane ND ND ND ND 16 μg/m3
1,1-Dichloropropene ND ND ND ND 10 μg/m3

JONES ENVIRONMENTAL QUALITY CONTROL INFORMATION
Mearns Consulting Group
738 Ashland Avenue,
Santa Monica CA 90405
2690 Walnut Ave
Signal Hill, CA
EPA 8260B – Volatile Organics by GC/MS + Oxygenates/Gasoline Range Organics Susan L Mearns PhD
Town Center Northwest
Reporting Limit Units

Page 10 of 14 ends

Sample ID: METHOD
BLANK

SAMPLING
BLANK
METHOD
BLANK

SAMPLING
BLANK
Jones ID: 072721-
E3MB1
072721-
E3SB1
072721-
E3MB1
072721-
E3SB1
Analytes:
cis-1,3-Dichloropropene ND ND ND ND 8 μg/m3
trans-1,3-Dichloropropene ND ND ND ND 8 μg/m3
Ethylbenzene ND ND ND ND 8 μg/m3
Freon 113 ND ND ND ND 16 μg/m3
Hexachlorobutadiene ND ND ND ND 24 μg/m3
Isopropylbenzene ND ND ND ND 8 μg/m3
4-Isopropyltoluene ND ND ND ND 8 μg/m3
Methylene chloride ND ND ND ND 8 μg/m3
Naphthalene ND ND ND ND 40 μg/m3
n-Propylbenzene ND ND ND ND 8 μg/m3
Styrene ND ND ND ND 8 μg/m3
1,1,1,2-Tetrachloroethane ND ND ND ND 8 μg/m3
1,1,2,2-Tetrachloroethane ND ND ND ND 16 μg/m3
Tetrachloroethene ND ND ND ND 8 μg/m3
Toluene ND ND ND ND 8 μg/m3
1,2,3-Trichlorobenzene ND ND ND ND 16 μg/m3
1,2,4-Trichlorobenzene ND ND ND ND 16 μg/m3
1,1,1-Trichloroethane ND ND ND ND 8 μg/m3
1,1,2-Trichloroethane ND ND ND ND 8 μg/m3
Trichloroethene ND ND ND ND 8 μg/m3
Trichlorofluoromethane ND ND ND ND 32 μg/m3
1,2,3-Trichloropropane ND ND ND ND 8 μg/m3
1,2,4-Trimethylbenzene ND ND ND ND 8 μg/m3
1,3,5-Trimethylbenzene ND ND ND ND 8 μg/m3
Vinyl chloride ND ND ND ND 8 μg/m3
m,p-Xylene ND ND ND ND 16 μg/m3
o-Xylene ND ND ND ND 8 μg/m3
MTBE ND ND ND ND 40 μg/m3
Ethyl-tert-butylether ND ND ND ND 40 μg/m3
Di-isopropylether ND ND ND ND 40 μg/m3
tert-amylmethylether ND ND ND ND 40 μg/m3
tert-Butylalcohol ND ND ND ND 400 μg/m3
Gasoline Range Organics (C4-C12) ND ND ND ND 2000 μg/m3 Tracer:
n-Pentane ND ND ND ND 80 μg/m3
n-Hexane ND ND ND ND 80 μg/m3
n-Heptane ND ND ND ND 80 μg/m3
Dilution Factor 1 1 1 1
Surrogate Recoveries:

Dibromofluoromethane 106% 100%
Toluene-d₈ 96% 96%
4-Bromofluorobenzene 93% 95%
Batch ID: E3-072721-
01 E3-072721-
01 E3-072721-
01 E3-072721-
01 ND = Value below reporting limit
EPA 8260B – Volatile Organics by GC/MS + Oxygenates/Gasoline Range Organics Reporting Limit Units
60 - 140

JONES ENVIRONMENTAL QUALITY CONTROL INFORMATION
60 - 140
60 - 140
QC Limits

Page 11 of 14 ends

Client: 7/27/2021
Client Address: E-1172
Attn: 7/27/2021
7/27/2021
Project: 7/27/2021
Project Address: Soil Gas
QC ID:

Jones ID: 072721-E3CCV1
Parameter RPD
Acceptability
Range (%) CCV
Acceptability
Range (%)
Vinyl chloride 5.7% 60 - 140 109% 80 - 120
1,1-Dichloroethene 8.1% 60 - 140 80% 80 - 120
Cis-1,2-Dichloroethene 3.5% 70 - 130 86% 80 - 120
1,1,1-Trichloroethane 6.6% 70 - 130 85% 80 - 120
Benzene 4.9% 70 - 130 101% 80 - 120
Trichloroethene 3.7% 70 - 130 101% 80 - 120
Toluene 4.2% 70 - 130 97% 80 - 120
Tetrachloroethene 2.0% 70 - 130 97% 80 - 120
Chlorobenzene 3.7% 70 - 130 95% 80 - 120
Ethylbenzene 9.2% 70 - 130 94% 80 - 120
1,2,4 Trimethylbenzene 1.2% 70 - 130 87% 80 - 120
Gasoline Range Organics (C4-C12) 5.0% 70 - 130 95% 80 - 120 Surrogate Recovery:

Dibromofluoromethane 60 - 140 100% 60 - 140
Toluene-d₈ 60 - 140 95% 60 - 140
4-Bromofluorobenzene 60 - 140 97% 60 - 140
RPD = Relative Percent Difference; Acceptability range for RPD is ≤ 20% LCS = Laboratory Control Sample
LCSD = Laboratory Control Sample Duplicate
CCV = Continuing Calibration Verification
102% 102%
97% 96%
96% 96%
99% 108%
92% 93%
102% 107%
109%
116% 114%
109% 113%
121% 114%
110% 101%
105% 102%
98% 104%
113% 119%
115% 119%
104%
E3-072721-01
072721-E3LCS1 072721-E3LCSD1
LCS
Recovery (%)
LCSD
Recovery (%)
2690 Walnut Ave Physical State:

Signal Hill, CA
EPA 8260B – Volatile Organics by GC/MS + Oxygenates/Gasoline Range Organics Susan L Mearns PhD Date Sampled:

Date Received:

Town Center Northwest Date Analyzed:
738 Ashland Avenue, Jones Ref. No.:

Santa Monica CA 90405

JONES ENVIRONMENTAL QUALITY CONTROL INFORMATION
Mearns Consulting Group Report date:

Page 12 of 14 ends

Page 13 of 14 ends

Page 14 of 14 ends

JONES ENVIRONMENTAL LABORATORY RESULTS

ANALYSES REQUESTED

Approval:

Annalise O’Toole
Mobile Lab Manager

Page 1 of 18 ends

Client: Report date: 7/28/2021
Client Address: Jones Ref. No.: E-1173
Attn: Date Sampled: 7/28/2021
Date Received: 7/28/2021
Project: Date Analyzed: 7/28/2021
Project Address: Physical State: Soil Gas
Sample ID: SV9-15' SV9-15'
REP SV10-5' SV10-15' SV11-5'
Jones ID: E-1173-01 E-1173-02 E-1173-03 E-1173-04 E-1173-05 Analytes:

Page 2 of 18 ends

Sample ID: SV9-15' SV9-15'
REP SV10-5' SV10-15' SV11-5'
Jones ID: E-1173-01 E-1173-02 E-1173-03 E-1173-04 E-1173-05 Analytes:
cis-1,3-Dichloropropene ND ND ND ND ND 8 μg/m3
trans-1,3-Dichloropropene ND ND ND ND ND 8 μg/m3
Ethylbenzene ND ND ND ND ND 8 μg/m3
Freon 113 ND ND ND ND ND 16 μg/m3
Hexachlorobutadiene ND ND ND ND ND 24 μg/m3
Isopropylbenzene ND ND ND ND ND 8 μg/m3
4-Isopropyltoluene ND ND ND ND ND 8 μg/m3
Methylene chloride ND ND ND ND ND 8 μg/m3
Naphthalene ND ND ND ND ND 40 μg/m3
n-Propylbenzene ND ND ND ND ND 8 μg/m3
Styrene ND ND ND ND ND 8 μg/m3
1,1,1,2-Tetrachloroethane ND ND ND ND ND 8 μg/m3
1,1,2,2-Tetrachloroethane ND ND ND ND ND 16 μg/m3
Tetrachloroethene 34 34 9 8 24 8 μg/m3
Toluene 13 14 ND ND ND 8 μg/m3
1,2,3-Trichlorobenzene ND ND ND ND ND 16 μg/m3
1,2,4-Trichlorobenzene ND ND ND ND ND 16 μg/m3
1,1,1-Trichloroethane ND ND ND ND ND 8 μg/m3
1,1,2-Trichloroethane ND ND ND ND ND 8 μg/m3
Trichloroethene ND ND ND ND ND 8 μg/m3
Trichlorofluoromethane ND ND ND ND ND 32 μg/m3
1,2,3-Trichloropropane ND ND ND ND ND 8 μg/m3
1,2,4-Trimethylbenzene ND ND ND ND ND 8 μg/m3
1,3,5-Trimethylbenzene ND ND ND ND ND 8 μg/m3
Vinyl chloride ND ND ND ND ND 8 μg/m3
m,p-Xylene ND ND ND ND ND 16 μg/m3
o-Xylene ND ND ND ND ND 8 μg/m3
MTBE ND ND ND ND ND 40 μg/m3
Ethyl-tert-butylether ND ND ND ND ND 40 μg/m3
Di-isopropylether ND ND ND ND ND 40 μg/m3
tert-amylmethylether ND ND ND ND ND 40 μg/m3
tert-Butylalcohol ND ND ND ND ND 400 μg/m3
Gasoline Range Organics (C4-C12) ND ND ND ND ND 2000 μg/m3 Tracer:
n-Pentane ND ND ND ND ND 80 μg/m3
n-Hexane ND ND ND ND ND 80 μg/m3
n-Heptane ND ND ND ND ND 80 μg/m3
Dilution Factor 1 1 1 1 1
Surrogate Recoveries:

Dibromofluoromethane 114%^ 119%^ 108% 123%^ 107%
Toluene-d₈ 103% 104% 89% 102% 89%
4-Bromofluorobenzene 108% @ 97% 108% 96%
Batch ID: E2-072821-
01 E2-072821-
01 E3-072821-
01 E2-072821-
01 E3-072821-
01 ^ = 1,2-dichloroethane-d4 used as surrogate for this batch.

ND = Value below reporting limit
@= Surrogate outside acceptable limits. All other QC parameters in control, therefore data was accepted. 60 - 140
60 - 140
Reporting Limit Units
60 - 140
QC Limits
EPA 8260B – Volatile Organics by GC/MS + Oxygenates/Gasoline Range Organics

JONES ENVIRONMENTAL LABORATORY RESULTS

Page 3 of 18 ends

Client: Report date: 7/28/2021
Client Address: Jones Ref. No.: E-1173
Attn: Date Sampled: 7/28/2021
Date Received: 7/28/2021
Project: Date Analyzed: 7/28/2021
Project Address: Physical State: Soil Gas
Sample ID: SV11-15' SV12-5' SV12-15' SV13-5' SV13-5'
REP
Jones ID: E-1173-06 E-1173-07 E-1173-08 E-1173-09 E-1173-10 Analytes:

JONES ENVIRONMENTAL LABORATORY RESULTS
Mearns Consulting Group
738 Ashland Avenue,
Santa Monica CA 90405

Page 4 of 18 ends

Sample ID: SV11-15' SV12-5' SV12-15' SV13-5' SV13-5'
REP
Jones ID: E-1173-06 E-1173-07 E-1173-08 E-1173-09 E-1173-10 Analytes:
cis-1,3-Dichloropropene ND ND ND ND ND 8 μg/m3
trans-1,3-Dichloropropene ND ND ND ND ND 8 μg/m3
Ethylbenzene ND ND ND ND ND 8 μg/m3
Freon 113 ND ND ND ND ND 16 μg/m3
Hexachlorobutadiene ND ND ND ND ND 24 μg/m3
Isopropylbenzene ND ND ND ND ND 8 μg/m3
4-Isopropyltoluene ND ND ND ND ND 8 μg/m3
Methylene chloride ND ND ND ND ND 8 μg/m3
Naphthalene ND ND ND ND ND 40 μg/m3
n-Propylbenzene ND ND ND ND ND 8 μg/m3
Styrene ND ND ND ND ND 8 μg/m3
1,1,1,2-Tetrachloroethane ND ND ND ND ND 8 μg/m3
1,1,2,2-Tetrachloroethane ND ND ND ND ND 16 μg/m3
Tetrachloroethene ND 8 9 16 25 8 μg/m3
Toluene ND ND ND ND ND 8 μg/m3
1,2,3-Trichlorobenzene ND ND ND ND ND 16 μg/m3
1,2,4-Trichlorobenzene ND ND ND ND ND 16 μg/m3
1,1,1-Trichloroethane ND ND ND ND ND 8 μg/m3
1,1,2-Trichloroethane ND ND ND ND ND 8 μg/m3
Trichloroethene ND ND ND ND ND 8 μg/m3
Trichlorofluoromethane ND ND ND ND ND 32 μg/m3
1,2,3-Trichloropropane ND ND ND ND ND 8 μg/m3
1,2,4-Trimethylbenzene ND ND ND ND ND 8 μg/m3
1,3,5-Trimethylbenzene ND ND ND ND ND 8 μg/m3
Vinyl chloride ND ND ND ND ND 8 μg/m3
m,p-Xylene ND ND ND ND ND 16 μg/m3
o-Xylene ND ND ND ND ND 8 μg/m3
MTBE ND ND ND ND ND 40 μg/m3
Ethyl-tert-butylether ND ND ND ND ND 40 μg/m3
Di-isopropylether ND ND ND ND ND 40 μg/m3
tert-amylmethylether ND ND ND ND ND 40 μg/m3
tert-Butylalcohol ND ND ND ND ND 400 μg/m3
Gasoline Range Organics (C4-C12) ND ND ND ND ND 2000 μg/m3 Tracer:
n-Pentane ND ND ND ND ND 80 μg/m3
n-Hexane ND ND ND ND ND 80 μg/m3
n-Heptane ND ND ND ND ND 80 μg/m3
Dilution Factor 1 1 1 1 1
Surrogate Recoveries:

Dibromofluoromethane 122%^ 105% 124%^ 106% 108%
Toluene-d₈ 105% 87% 102% 87% 88%
4-Bromofluorobenzene 107% 97% 105% 96% 96%
Batch ID: E2-072821-
01 E3-072821-
01 E2-072821-
01 E3-072821-
01 E3-072821-
01 ND = Value below reporting limit
^ = 1,2-dichloroethane-d4 used as surrogate for this batch. 60 - 140
60 - 140
60 - 140

JONES ENVIRONMENTAL LABORATORY RESULTS
EPA 8260B – Volatile Organics by GC/MS + Oxygenates/Gasoline Range Organics Reporting Limit Units
QC Limits

Page 5 of 18 ends

Client: Report date: 7/28/2021
Client Address: Jones Ref. No.: E-1173
Attn: Date Sampled: 7/28/2021
Date Received: 7/28/2021
Project: Date Analyzed: 7/28/2021
Project Address: Physical State: Soil Gas
Sample ID: SV13-15' SV14-5' SV14-15' SV15-5' SV15-15'
Jones ID: E-1173-11 E-1173-12 E-1173-13 E-1173-14 E-1173-15 Analytes:

JONES ENVIRONMENTAL LABORATORY RESULTS
Mearns Consulting Group
738 Ashland Avenue,
Santa Monica CA 90405

Page 6 of 18 ends

Sample ID: SV13-15' SV14-5' SV14-15' SV15-5' SV15-15'
Jones ID: E-1173-11 E-1173-12 E-1173-13 E-1173-14 E-1173-15 Analytes:
cis-1,3-Dichloropropene ND ND ND ND ND 8 μg/m3
trans-1,3-Dichloropropene ND ND ND ND ND 8 μg/m3
Ethylbenzene ND ND ND ND ND 8 μg/m3
Freon 113 ND ND ND ND ND 16 μg/m3
Hexachlorobutadiene ND ND ND ND ND 24 μg/m3
Isopropylbenzene ND ND ND ND ND 8 μg/m3
4-Isopropyltoluene ND ND ND ND ND 8 μg/m3
Methylene chloride ND ND ND ND ND 8 μg/m3
Naphthalene ND ND ND ND ND 40 μg/m3
n-Propylbenzene ND ND ND ND ND 8 μg/m3
Styrene ND ND ND ND ND 8 μg/m3
1,1,1,2-Tetrachloroethane ND ND ND ND ND 8 μg/m3
1,1,2,2-Tetrachloroethane ND ND ND ND ND 16 μg/m3
Tetrachloroethene ND 10 ND 37 29 8 μg/m3
Toluene ND ND ND ND ND 8 μg/m3
1,2,3-Trichlorobenzene ND ND ND ND ND 16 μg/m3
1,2,4-Trichlorobenzene ND ND ND ND ND 16 μg/m3
1,1,1-Trichloroethane ND ND ND ND ND 8 μg/m3
1,1,2-Trichloroethane ND ND ND ND ND 8 μg/m3
Trichloroethene ND ND ND ND ND 8 μg/m3
Trichlorofluoromethane ND ND ND ND ND 32 μg/m3
1,2,3-Trichloropropane ND ND ND ND ND 8 μg/m3
1,2,4-Trimethylbenzene ND ND ND ND ND 8 μg/m3
1,3,5-Trimethylbenzene ND ND ND ND ND 8 μg/m3
Vinyl chloride ND ND ND ND ND 8 μg/m3
m,p-Xylene ND ND ND ND ND 16 μg/m3
o-Xylene ND ND ND ND ND 8 μg/m3
MTBE ND ND ND ND ND 40 μg/m3
Ethyl-tert-butylether ND ND ND ND ND 40 μg/m3
Di-isopropylether ND ND ND ND ND 40 μg/m3
tert-amylmethylether ND ND ND ND ND 40 μg/m3
tert-Butylalcohol ND ND ND ND ND 400 μg/m3
Gasoline Range Organics (C4-C12) ND ND ND ND ND 2000 μg/m3 Tracer:
n-Pentane ND ND ND ND ND 80 μg/m3
n-Hexane ND ND ND ND ND 80 μg/m3
n-Heptane ND ND ND ND ND 80 μg/m3
Dilution Factor 1 1 1 1 1
Surrogate Recoveries:

Dibromofluoromethane 126%^ 108% 123%^ 105% 119%^
Toluene-d₈ 106% 85% 102% 86% 101%
4-Bromofluorobenzene 106% 98% 104% 95% 82%
Batch ID: E2-072821-
01 E3-072821-
01 E2-072821-
01 E3-072821-
01 E2-072821-
01 ND = Value below reporting limit
^ = 1,2-dichloroethane-d4 used as surrogate for this batch. 60 - 140
60 - 140
60 - 140

JONES ENVIRONMENTAL LABORATORY RESULTS
EPA 8260B – Volatile Organics by GC/MS + Oxygenates/Gasoline Range Organics Reporting Limit Units
QC Limits

Page 7 of 18 ends

Client: Report date: 7/28/2021
Client Address: Jones Ref. No.: E-1173
Attn: Date Sampled: 7/28/2021
Date Received: 7/28/2021
Project: Date Analyzed: 7/28/2021
Project Address: Physical State: Soil Gas
Sample ID: SV16-5' SV16-15' SV17-5' SV17-15' SV18-5'
Jones ID: E-1173-16 E-1173-17 E-1173-18 E-1173-19 E-1173-20 Analytes:

Benzene ND 27 ND ND ND 8 μg/m3
Bromobenzene ND ND ND ND ND 8 μg/m3
Bromodichloromethane ND ND ND ND ND 8 μg/m3
Bromoform ND ND ND ND ND 8 μg/m3
n-Butylbenzene ND ND ND ND ND 12 μg/m3
sec-Butylbenzene ND ND ND ND ND 12 μg/m3
tert-Butylbenzene ND ND ND ND ND 12 μg/m3
Carbon tetrachloride ND ND ND ND ND 8 μg/m3
Chlorobenzene ND ND ND ND ND 8 μg/m3
Chloroform ND ND ND ND ND 8 μg/m3
2-Chlorotoluene ND ND ND ND ND 12 μg/m3
4-Chlorotoluene ND ND ND ND ND 12 μg/m3
Dibromochloromethane ND ND ND ND ND 8 μg/m3
1,2-Dibromo-3-chloropropane ND ND ND ND ND 8 μg/m3
1,2-Dibromoethane (EDB) ND ND ND ND ND 8 μg/m3
Dibromomethane ND ND ND ND ND 8 μg/m3
1,2- Dichlorobenzene ND ND ND ND ND 16 μg/m3
1,3-Dichlorobenzene ND ND ND ND ND 16 μg/m3
1,4-Dichlorobenzene ND ND ND ND ND 16 μg/m3
Dichlorodifluoromethane ND ND ND ND ND 32 μg/m3
1,1-Dichloroethane ND ND ND ND ND 8 μg/m3
1,2-Dichloroethane ND ND ND ND ND 8 μg/m3
1,1-Dichloroethene ND ND ND ND ND 8 μg/m3
cis-1,2-Dichloroethene ND 51 ND ND ND 8 μg/m3
trans-1,2-Dichloroethene ND ND ND ND ND 8 μg/m3
1,2-Dichloropropane ND ND ND ND ND 8 μg/m3
1,3-Dichloropropane ND ND ND ND ND 8 μg/m3
2,2-Dichloropropane ND ND ND ND ND 16 μg/m3
1,1-Dichloropropene ND ND ND ND ND 10 μg/m3
Reporting Limit Units
Susan L Mearns PhD
Town Center Northwest
2690 Walnut Ave
Signal Hill, CA
EPA 8260B – Volatile Organics by GC/MS + Oxygenates/Gasoline Range Organics

JONES ENVIRONMENTAL LABORATORY RESULTS
Mearns Consulting Group
738 Ashland Avenue,
Santa Monica CA 90405

Page 8 of 18 ends

Sample ID: SV16-5' SV16-15' SV17-5' SV17-15' SV18-5'
Jones ID: E-1173-16 E-1173-17 E-1173-18 E-1173-19 E-1173-20 Analytes:
cis-1,3-Dichloropropene ND ND ND ND ND 8 μg/m3
trans-1,3-Dichloropropene ND ND ND ND ND 8 μg/m3
Ethylbenzene ND 74 ND ND ND 8 μg/m3
Freon 113 ND ND ND ND ND 16 μg/m3
Hexachlorobutadiene ND ND ND ND ND 24 μg/m3
Isopropylbenzene ND ND ND ND ND 8 μg/m3
4-Isopropyltoluene ND 16 ND ND ND 8 μg/m3
Methylene chloride ND ND ND ND ND 8 μg/m3
Naphthalene ND 41 ND ND ND 40 μg/m3
n-Propylbenzene ND ND ND ND ND 8 μg/m3
Styrene ND ND ND ND ND 8 μg/m3
1,1,1,2-Tetrachloroethane ND ND ND ND ND 8 μg/m3
1,1,2,2-Tetrachloroethane ND ND ND ND ND 16 μg/m3
Tetrachloroethene 15 18 32 10 13 8 μg/m3
Toluene ND 44 ND ND ND 8 μg/m3
1,2,3-Trichlorobenzene ND ND ND ND ND 16 μg/m3
1,2,4-Trichlorobenzene ND ND ND ND ND 16 μg/m3
1,1,1-Trichloroethane ND ND ND ND ND 8 μg/m3
1,1,2-Trichloroethane ND ND ND ND ND 8 μg/m3
Trichloroethene ND ND ND ND ND 8 μg/m3
Trichlorofluoromethane ND ND ND ND ND 32 μg/m3
1,2,3-Trichloropropane ND ND ND ND ND 8 μg/m3
1,2,4-Trimethylbenzene ND ND ND ND ND 8 μg/m3
1,3,5-Trimethylbenzene ND ND ND ND ND 8 μg/m3
Vinyl chloride ND ND ND ND ND 8 μg/m3
m,p-Xylene ND 287 ND ND ND 16 μg/m3
o-Xylene ND 84 ND ND ND 8 μg/m3
MTBE ND ND ND ND ND 40 μg/m3
Ethyl-tert-butylether ND ND ND ND ND 40 μg/m3
Di-isopropylether ND ND ND ND ND 40 μg/m3
tert-amylmethylether ND ND ND ND ND 40 μg/m3
tert-Butylalcohol ND ND ND ND ND 400 μg/m3
Gasoline Range Organics (C4-C12) ND 46800 ND ND ND 2000 μg/m3 Tracer:
n-Pentane ND ND ND ND ND 80 μg/m3
n-Hexane ND ND ND ND ND 80 μg/m3
n-Heptane ND ND ND ND ND 80 μg/m3
Dilution Factor 1 1 1 1 1
Surrogate Recoveries:

Dibromofluoromethane 112% 124%^ 108% 121%^ 106%
Toluene-d₈ 86% 101% 85% 99% 86%
4-Bromofluorobenzene 97% 114% 96% 104% 97%
Batch ID: E3-072821-
01 E2-072821-
01 E3-072821-
01 E2-072821-
01 E3-072821-
01 60 - 140
ND = Value below reporting limit
^ = 1,2-dichloroethane-d4 used as surrogate for this batch.

EPA 8260B – Volatile Organics by GC/MS + Oxygenates/Gasoline Range Organics Reporting Limit Units
QC Limits
60 - 140
60 - 140

JONES ENVIRONMENTAL LABORATORY RESULTS

Page 9 of 18 ends

Client: Report date: 7/28/2021
Client Address: Jones Ref. No.: E-1173
Attn: Date Sampled: 7/28/2021
Date Received: 7/28/2021
Project: Date Analyzed: 7/28/2021
Project Address: Physical State: Soil Gas
Sample ID: SV18-15' SV19-5'
Jones ID: E-1173-21 E-1173-22 - -
Analytes:

Benzene 1150 18 ND ND ND 8 μg/m3
Bromobenzene ND ND ND ND ND 8 μg/m3
Bromodichloromethane ND ND ND ND ND 8 μg/m3
Bromoform ND ND ND ND ND 8 μg/m3
n-Butylbenzene ND 649 ND ND ND 12 μg/m3
sec-Butylbenzene ND 2380 ND ND ND 12 μg/m3
tert-Butylbenzene ND ND ND ND ND 12 μg/m3
Carbon tetrachloride ND ND ND ND ND 8 μg/m3
Chlorobenzene ND ND ND ND ND 8 μg/m3
Chloroform ND ND ND ND ND 8 μg/m3
2-Chlorotoluene ND ND ND ND ND 12 μg/m3
4-Chlorotoluene ND ND ND ND ND 12 μg/m3
Dibromochloromethane ND ND ND ND ND 8 μg/m3
1,2-Dibromo-3-chloropropane ND ND ND ND ND 8 μg/m3
1,2-Dibromoethane (EDB) ND ND ND ND ND 8 μg/m3
Dibromomethane ND ND ND ND ND 8 μg/m3
1,2- Dichlorobenzene ND ND ND ND ND 16 μg/m3
1,3-Dichlorobenzene ND ND ND ND ND 16 μg/m3
1,4-Dichlorobenzene ND ND ND ND ND 16 μg/m3
Dichlorodifluoromethane ND ND ND ND ND 32 μg/m3
1,1-Dichloroethane ND ND ND ND ND 8 μg/m3
1,2-Dichloroethane ND ND ND ND ND 8 μg/m3
1,1-Dichloroethene ND ND ND ND ND 8 μg/m3
cis-1,2-Dichloroethene ND ND ND ND ND 8 μg/m3
trans-1,2-Dichloroethene ND ND ND ND ND 8 μg/m3
1,2-Dichloropropane ND ND ND ND ND 8 μg/m3
1,3-Dichloropropane ND ND ND ND ND 8 μg/m3
2,2-Dichloropropane ND ND ND ND ND 16 μg/m3
1,1-Dichloropropene ND ND ND ND ND 10 μg/m3
EPA 8260B – Volatile Organics by GC/MS + Oxygenates/Gasoline Range Organics

JONES ENVIRONMENTAL LABORATORY RESULTS
Mearns Consulting Group
738 Ashland Avenue,
Santa Monica CA 90405
Susan L Mearns PhD
Town Center Northwest
2690 Walnut Ave
Signal Hill, CA
Reporting Limit Units

Page 10 of 18 ends

Sample ID: SV18-15' SV19-5'
Jones ID: E-1173-21 E-1173-22 - -
Analytes:
cis-1,3-Dichloropropene ND ND ND ND ND 8 μg/m3
trans-1,3-Dichloropropene ND ND ND ND ND 8 μg/m3
Ethylbenzene 1910 2730 ND ND ND 8 μg/m3
Freon 113 ND ND ND ND ND 16 μg/m3
Hexachlorobutadiene ND ND ND ND ND 24 μg/m3
Isopropylbenzene 2490 4290 ND ND ND 8 μg/m3
4-Isopropyltoluene ND 13 ND ND ND 8 μg/m3
Methylene chloride ND ND ND ND ND 8 μg/m3
Naphthalene 826 405 ND ND ND 40 μg/m3
n-Propylbenzene 2640 5810 ND ND ND 8 μg/m3
Styrene ND ND ND ND ND 8 μg/m3
1,1,1,2-Tetrachloroethane ND ND ND ND ND 8 μg/m3
1,1,2,2-Tetrachloroethane ND ND ND ND ND 16 μg/m3
Tetrachloroethene ND 42 ND ND ND 8 μg/m3
Toluene ND 25 ND ND ND 8 μg/m3
1,2,3-Trichlorobenzene ND ND ND ND ND 16 μg/m3
1,2,4-Trichlorobenzene ND ND ND ND ND 16 μg/m3
1,1,1-Trichloroethane ND ND ND ND ND 8 μg/m3
1,1,2-Trichloroethane ND ND ND ND ND 8 μg/m3
Trichloroethene ND ND ND ND ND 8 μg/m3
Trichlorofluoromethane ND ND ND ND ND 32 μg/m3
1,2,3-Trichloropropane ND ND ND ND ND 8 μg/m3
1,2,4-Trimethylbenzene ND ND ND ND ND 8 μg/m3
1,3,5-Trimethylbenzene ND ND ND ND ND 8 μg/m3
Vinyl chloride ND ND ND ND ND 8 μg/m3
m,p-Xylene 1720 ND ND ND ND 16 μg/m3
o-Xylene ND ND ND ND ND 8 μg/m3
MTBE 8610 121000* ND ND ND 40 μg/m3
Ethyl-tert-butylether ND ND ND ND ND 40 μg/m3
Di-isopropylether 4780 ND ND ND ND 40 μg/m3
tert-amylmethylether ND ND ND ND ND 40 μg/m3
tert-Butylalcohol ND ND ND ND ND 400 μg/m3
Gasoline Range Organics (C4-C12) 3380000 900000 ND ND ND 2000 μg/m3 Tracer:
n-Pentane ND ND ND ND ND 80 μg/m3
n-Hexane ND ND ND ND ND 80 μg/m3
n-Heptane ND ND ND ND ND 80 μg/m3
Dilution Factor 12.5 1/3* 1 1 1
Surrogate Recoveries:

Dibromofluoromethane 115% 103%
Toluene-d₈ 106% 115%
4-Bromofluorobenzene 123% ●
Batch ID: E2-072721-
01 E3-072721-
01 E2-072721-
01 E3-072721-
01 * = Dilutions for these compound(s); first number for all others 60 - 140
60 - 140
60 - 140
ND = Value below reporting limit

JONES ENVIRONMENTAL LABORATORY RESULTS
EPA 8260B – Volatile Organics by GC/MS + Oxygenates/Gasoline Range Organics Reporting Limit Units
QC Limits
^ = 1,2-dichloroethane-d4 used as surrogate for this batch. ● = Hydrocarbon interference prevented adequate surrogate recovery.

Page 11 of 18 ends

SAMPLING
BLANK
METHOD
BLANK

SAMPLING
BLANK
Jones ID: 072821-
E2MB1
072821-
E2SB1
072821-
E3MB1
072821-
E3SB1
Analytes:

Page 12 of 18 ends

Sample ID: METHOD
BLANK

SAMPLING
BLANK
METHOD
BLANK

SAMPLING
BLANK
Jones ID: 072821-
E2MB1
072821-
E2SB1
072821-
E3MB1
072821-
E3SB1
Analytes:
cis-1,3-Dichloropropene ND ND ND ND 8 μg/m3
trans-1,3-Dichloropropene ND ND ND ND 8 μg/m3
Ethylbenzene ND ND ND ND 8 μg/m3
Freon 113 ND ND ND ND 16 μg/m3
Hexachlorobutadiene ND ND ND ND 24 μg/m3
Isopropylbenzene ND ND ND ND 8 μg/m3
4-Isopropyltoluene ND ND ND ND 8 μg/m3
Methylene chloride ND ND ND ND 8 μg/m3
Naphthalene ND ND ND ND 40 μg/m3
n-Propylbenzene ND ND ND ND 8 μg/m3
Styrene ND ND ND ND 8 μg/m3
1,1,1,2-Tetrachloroethane ND ND ND ND 8 μg/m3
1,1,2,2-Tetrachloroethane ND ND ND ND 16 μg/m3
Tetrachloroethene ND ND ND ND 8 μg/m3
Toluene ND ND ND ND 8 μg/m3
1,2,3-Trichlorobenzene ND ND ND ND 16 μg/m3
1,2,4-Trichlorobenzene ND ND ND ND 16 μg/m3
1,1,1-Trichloroethane ND ND ND ND 8 μg/m3
1,1,2-Trichloroethane ND ND ND ND 8 μg/m3
Trichloroethene ND ND ND ND 8 μg/m3
Trichlorofluoromethane ND ND ND ND 32 μg/m3
1,2,3-Trichloropropane ND ND ND ND 8 μg/m3
1,2,4-Trimethylbenzene ND ND ND ND 8 μg/m3
1,3,5-Trimethylbenzene ND ND ND ND 8 μg/m3
Vinyl chloride ND ND ND ND 8 μg/m3
m,p-Xylene ND ND ND ND 16 μg/m3
o-Xylene ND ND ND ND 8 μg/m3
MTBE ND ND ND ND 40 μg/m3
Ethyl-tert-butylether ND ND ND ND 40 μg/m3
Di-isopropylether ND ND ND ND 40 μg/m3
tert-amylmethylether ND ND ND ND 40 μg/m3
tert-Butylalcohol ND ND ND ND 400 μg/m3
Gasoline Range Organics (C4-C12) ND ND ND ND 2000 μg/m3 Tracer:
n-Pentane ND ND ND ND 80 μg/m3
n-Hexane ND ND ND ND 80 μg/m3
n-Heptane ND ND ND ND 80 μg/m3
Dilution Factor 1 1 1 1
Surrogate Recoveries:

Dibromofluoromethane 121%^ 114%^ 105% 100%
Toluene-d₈ 100% 104% 93% 90%
4-Bromofluorobenzene 106% 107% 98% 96%
Batch ID: E2-072821-
01 E2-072821-
01 E3-072721-
01 E3-072721-
01 ND = Value below reporting limit
EPA 8260B – Volatile Organics by GC/MS + Oxygenates/Gasoline Range Organics Reporting Limit Units
^ = 1,2-dichloroethane-d4 used as surrogate for this batch. 60 - 140

JONES ENVIRONMENTAL QUALITY CONTROL INFORMATION
60 - 140
60 - 140
QC Limits

Page 13 of 18 ends

Client: 7/28/2021
Client Address: E-1173
Attn: 7/28/2021
7/28/2021
Project: 7/28/2021
Project Address: Soil Gas
Batch ID:

Jones ID:

Parameter RPD
Acceptability
Range (%) CCV
Acceptability
Range (%)
Vinyl chloride 6.2% 60 - 140 50%1
80 - 120
1,1-Dichloroethene 3.7% 60 - 140 103% 80 - 120
Cis-1,2-Dichloroethene 4.0% 70 - 130 106% 80 - 120
1,1,1-Trichloroethane 2.5% 70 - 130 112% 80 - 120
Benzene 4.4% 70 - 130 110% 80 - 120
Trichloroethene 5.9% 70 - 130 103% 80 - 120
Toluene 6.8% 70 - 130 116% 80 - 120
Tetrachloroethene 3.9% 70 - 130 120% 80 - 120
Chlorobenzene 2.3% 70 - 130 96% 80 - 120
Ethylbenzene 6.3% 70 - 130 87% 80 - 120
1,2,4 Trimethylbenzene 3.1% 70 - 130 118% 80 - 120
Gasoline Range Organics (C4-C12) 5.0% 70 - 130 108% 80 - 120 Surrogate Recovery:
1,2-Dichloroethane-d4 60 - 140 110% 60 - 140
Toluene-d₈ 60 - 140 102% 60 - 140
4-Bromofluorobenzene 60 - 140 108% 60 - 140
072821-E2CCV1
129%
106%
124%
124% 121%
129%
Town Center Northwest Date Analyzed:
2690 Walnut Ave
Date Received:

LCSD = Laboratory Control Sample Duplicate
RPD = Relative Percent Difference; Acceptability range for RPD is ≤ 20% 1Recovery outside of acceptable limits. If compound was found in sample, the sample would have been re-ran for confirmation.

LCS = Laboratory Control Sample
2Recovery outside of acceptable limits. CCV and LCS recoveries and LCS/LCSD RPD were within QC limits, therefore data was accepted. 120% 119%
102%
105% 105%
109% 115%
134%2
78%
Mearns Consulting Group Report date:
738 Ashland Avenue,
Susan L Mearns PhD

JONES ENVIRONMENTAL QUALITY CONTROL INFORMATION
Jones Ref. No.:

Date Sampled:

Santa Monica CA 90405
Physical State:

LCS
Recovery (%)
LCSD
Recovery (%)
112%
101%
EPA 8260B – Volatile Organics by GC/MS + Oxygenates/Gasoline Range Organics 072821-E2LCS1 072821-E2LCSD1
124%
Signal Hill, CA
E2-072821-01
CCV = Continuing Calibration Verification
142%1
121%
119%
120% 128%
123%
83%
151%1
126%
99% 101%
119%

Page 14 of 18 ends

Client: 7/28/2021
Client Address: E-1173
Attn: 7/28/2021
7/28/2021
Project: 7/28/2021
Project Address: Soil Gas
QC ID:

Jones ID:

Parameter RPD
Acceptability
Range (%) CCV
Acceptability
Range (%)
Vinyl chloride 2.2% 60 - 140 100% 80 - 120
1,1-Dichloroethene 8.9% 60 - 140 94% 80 - 120
Cis-1,2-Dichloroethene 1.8% 70 - 130 101% 80 - 120
1,1,1-Trichloroethane 2.4% 70 - 130 99% 80 - 120
Benzene 0.3% 70 - 130 118% 80 - 120
Trichloroethene 12.1% 70 - 130 109% 80 - 120
Toluene 1.6% 70 - 130 105% 80 - 120
Tetrachloroethene 5.8% 70 - 130 103% 80 - 120
Chlorobenzene 0.7% 70 - 130 112% 80 - 120
Ethylbenzene 4.3% 70 - 130 106% 80 - 120
1,2,4 Trimethylbenzene 0.3% 70 - 130 99% 80 - 120
Gasoline Range Organics (C4-C12) 1.4% 70 - 130 107% 80 - 120 Surrogate Recovery:

Dibromofluoromethane 60 - 140 100% 60 - 140
Toluene-d₈ 60 - 140 93% 60 - 140
4-Bromofluorobenzene 60 - 140 98% 60 - 140
072821-E3CCV1
RPD = Relative Percent Difference; Acceptability range for RPD is ≤ 20% LCS = Laboratory Control Sample
LCSD = Laboratory Control Sample Duplicate
CCV = Continuing Calibration Verification
100% 102%
94% 94%
97% 100%
103% 99%
91% 91%
106% 104%
103%
106% 112%
110% 109%
83% 81%
110% 101%
111% 109%
100% 98%
124% 124%
126% 112%
104%
E3-072821-01
072821-E3LCS1 072821-E3LCSD1
LCS
Recovery (%)
LCSD
Recovery (%)
2690 Walnut Ave Physical State:

Signal Hill, CA
EPA 8260B – Volatile Organics by GC/MS + Oxygenates/Gasoline Range Organics Susan L Mearns PhD Date Sampled:

Date Received:

Town Center Northwest Date Analyzed:
738 Ashland Avenue, Jones Ref. No.:

Santa Monica CA 90405

JONES ENVIRONMENTAL QUALITY CONTROL INFORMATION
Mearns Consulting Group Report date:

Page 15 of 18 ends

Page 16 of 18 ends

Page 17 of 18 ends

Page 18 of 18 ends

APPENDIX C
Boring Logs

APPENDIX D
Sierra Analytical Labs, Inc.

Background Soil Matrix Analytical Data
April 2005 & July 2021
Project:

Project Number:

Project Manager:

Reported:

Mearns Consulting Corporation
738 Ashland Avenue Las Brisas
Santa Monica CA, 90405 Susan Mearns 04/12/05 14:01
City of Signal Hill
Metals by EPA 6000/7000 Series Methods
Sierra Analytical Labs, Inc.

Analyte Limit Result
Reporting
Units Dilution Batch Prepared Analyzed Method Notes
Offsite-1 (0504072-33) Soil Sampled: 04/04/05 13:20 Received: 04/04/05 14:15 Silver ND 0.80 mg/kg B5D0709 1 04/07/05 04/11/05 EPA 6010B Arsenic 5.2 1.7 "" "" " "
Barium 97 3.3 "" "" " "
Beryllium ND 0.75 "" " "" "
Cadmium ND 0.51 "" " "" "
Cobalt 8.1 2.2 "" "" " "
Chromium 21 0.98 "" "" " "
Copper 25 2.2 "" "" " "
Mercury ND 0.16 " " B5D0711 04/07/05 04/08/05 EPA 7471A Molybdenum ND 1.7 " B5D0709 " 04/07/05 04/11/05 EPA 6010B Nickel 12 0.79 "" "" " "
Lead 12 1.3 "" "" " "
Antimony ND 1.6 "" " "" "
Selenium ND 1.9 "" " "" "
Thallium ND 1.5 "" " "" "
Vanadium 35 0.73 "" "" " "
Zinc 62 1.3 "" "" " "
Offsite-5 (0504072-34) Soil Sampled: 04/04/05 13:25 Received: 04/04/05 14:15 Silver ND 0.80 mg/kg B5D0709 1 04/07/05 04/11/05 EPA 6010B Arsenic 12 1.7 "" "" " "
Barium 160 3.3 "" "" " "
Beryllium 1.1 0.75 "" "" " "
Cadmium ND 0.51 "" " "" "
Cobalt 17 2.2 "" "" " "
Chromium 50 0.98 "" "" " "
Copper 64 2.2 "" "" " "
Mercury ND 0.18 " " B5D0711 04/07/05 04/08/05 EPA 7471A Molybdenum ND 1.7 " B5D0709 " 04/07/05 04/11/05 EPA 6010B Nickel 30 0.79 "" "" " "
Lead 8.1 1.3 "" "" " "
Antimony 2.3 1.6 "" "" " "
Selenium ND 1.9 "" " "" "
Thallium ND 1.5 "" " "" "
Vanadium 75 0.73 "" "" " "
Zinc 99 1.3 "" "" " "

Page 19 of 79 ends

Project Number:

Project Manager:

Reported:

Mearns Consulting Corporation
738 Ashland Avenue Las Brisas
Santa Monica CA, 90405 Susan Mearns 04/12/05 14:01
City of Signal Hill
Metals by EPA 6000/7000 Series Methods
Sierra Analytical Labs, Inc.

Analyte Limit Result
Reporting
Units Dilution Batch Prepared Analyzed Method Notes
Offsite-10 (0504072-35) Soil Sampled: 04/04/05 13:29 Received: 04/04/05 14:15 Silver ND 0.80 mg/kg B5D0709 1 04/07/05 04/11/05 EPA 6010B Arsenic 12 1.7 "" "" " "
Barium 170 3.3 "" "" " "
Beryllium ND 0.75 "" " "" "
Cadmium ND 0.51 "" " "" "
Cobalt 14 2.2 "" "" " "
Chromium 32 0.98 "" "" " "
Copper 35 2.2 "" "" " "
Mercury ND 0.18 " " B5D0711 04/07/05 04/08/05 EPA 7471A Molybdenum ND 1.7 " B5D0709 " 04/07/05 04/11/05 EPA 6010B Nickel 22 0.79 "" "" " "
Lead 5.6 1.3 "" "" " "
Antimony ND 1.6 "" " "" "
Selenium ND 1.9 "" " "" "
Thallium ND 1.5 "" " "" "
Vanadium 58 0.73 "" "" " "
Zinc 67 1.3 "" "" " "
Offsite-20 (0504072-36) Soil Sampled: 04/04/05 13:36 Received: 04/04/05 14:15 Silver ND 0.80 mg/kg B5D0709 1 04/07/05 04/11/05 EPA 6010B Arsenic 14 1.7 "" "" " "
Barium 73 3.3 "" "" " "
Beryllium 0.95 0.75 "" "" " "
Cadmium ND 0.51 "" " "" "
Cobalt 17 2.2 "" "" " "
Chromium 35 0.98 "" "" " "
Copper 80 2.2 "" "" " "
Mercury ND 0.15 " " B5D0711 04/07/05 04/08/05 EPA 7471A Molybdenum ND 1.7 " B5D0709 " 04/07/05 04/11/05 EPA 6010B Nickel 22 0.79 "" "" " "
Lead 10 1.3 "" "" " "
Antimony ND 1.6 "" " "" "
Selenium ND 1.9 "" " "" "
Thallium ND 1.5 "" " "" "
Vanadium 67 0.73 "" "" " "
Zinc 95 1.3 "" "" " "

Page 20 of 79 ends

The results in this report apply to the samples analyzed in accordance with the chain of custody document. This analytical report must be reproduced in its entirety. 26052 MERIT CIRCLE SUITE 105, LAGUNA HILLS, CALIFORNIA 92653 TELEPHONE: (949) 348-9389 FAX: (949) 348-9115
E-MAIL: SIERRALABS @ SIERRALABS.NET
Mearns Consulting LLC
RE:1905 E 21st St. - Spud Field
Santa Monica, CA 90405
738 Ashland Avenue
Susan Mearns
Attached are the results of the analyses for samples received by the laboratory on 07/06/21 14:35.

The samples were received by Sierra Analytical Labs, Inc. with a chain of custody record attached or completed at the submittal of the samples.

The analyses were performed according to the prescribed method as outlined by EPA, Standard Methods, and A.S.T.M.

The remaining portions of the samples will be disposed of within 30 days from the date of this report.

If you require any additional retaining time, please advise us.

Sincerely,
13 July 2021
Richard K. Forsyth
Laboratory Director
Work Order No.: 2107058
Sierra Analytical Labs, Inc. is certified by the California Department of Health Services (DOHS), Environmental Laboratory Accredidation Program (ELAP) No. 2320.

Project:

Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/13/21 12:23
1905 E 21st St. - Spud Field
Sample ID Laboratory ID Matrix Date Sampled

ANALYTICAL REPORT FOR SAMPLES
Date Received
SB1-5 2107058-01 Soil 07/06/21 07:40 07/06/21 14:35
SB2-5 2107058-02 Soil 07/06/21 07:51 07/06/21 14:35
SB3-5 2107058-03 Soil 07/06/21 08:01 07/06/21 14:35
SB4-5 2107058-04 Soil 07/06/21 08:08 07/06/21 14:35
SB5-5 2107058-05 Soil 07/06/21 08:16 07/06/21 14:35
SB6-5 2107058-06 Soil 07/06/21 08:23 07/06/21 14:35
SB7-5 2107058-07 Soil 07/06/21 08:31 07/06/21 14:35
SB8-5 2107058-08 Soil 07/06/21 08:38 07/06/21 14:35
SB9-5 2107058-09 Soil 07/06/21 08:47 07/06/21 14:35
SB10-5 2107058-10 Soil 07/06/21 08:58 07/06/21 14:35
SB11-5 2107058-11 Soil 07/06/21 09:10 07/06/21 14:35

Page 1 of 12 ends

Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/13/21 12:23
1905 E 21st St. - Spud Field
Metals by EPA 6000/7000 Series Methods
Sierra Analytical Labs, Inc.

Analyte Result Limit
Reporting
Units Dilution Batch Prepared Analyzed Method Notes
SB1-5 (2107058-01) Soil Sampled: 07/06/21 07:40 Received: 07/06/21 14:35 Silver ND 2.0 mg/kg 1 B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Arsenic ND 5.5 " " " " " "
Barium 84 6.0 " " " " " "
Beryllium ND 2.2 " " " " " "
Cadmium ND 2.5 " " " " " "
Cobalt 11 3.3 " " " " " "
Chromium 36 2.3 " " " " " "
Hexavalent Chromium ND 0.10 " " B1G0711 07/07/21 07/09/21 12:47 EPA 7199A Copper 40 5.0 " " B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Mercury ND 0.90 " " B1G0613 07/06/21 07/06/21 20:35 EPA 7471A Molybdenum ND 5.2 " " B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Nickel 21 3.0 " " " " " "
Lead 8.8 7.1 " " " " " "
Antimony ND 8.0 " " " " " "
Selenium ND 6.9 " " " " " "
Thallium ND 17 " " " " " "
Vanadium 46 5.1 " " " " " "
Zinc 54 7.0 " " " " " "
SB2-5 (2107058-02) Soil Sampled: 07/06/21 07:51 Received: 07/06/21 14:35 Silver ND 2.0 mg/kg 1 B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Arsenic ND 5.5 " " " " " "
Barium 69 6.0 " " " " " "
Beryllium ND 2.2 " " " " " "
Cadmium ND 2.5 " " " " " "
Cobalt 9.3 3.3 " " " " " "
Chromium 21 2.3 " " " " " "
Hexavalent Chromium ND 0.10 " " B1G0711 07/07/21 07/09/21 12:47 EPA 7199A Copper 26 5.0 " " B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Mercury ND 0.90 " " B1G0613 07/06/21 07/06/21 20:35 EPA 7471A Molybdenum ND 5.2 " " B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Nickel 15 3.0 " " " " " "
Lead ND 7.1 " " " " " "
Antimony ND 8.0 " " " " " "
Selenium ND 6.9 " " " " " "
Thallium ND 17 " " " " " "
Vanadium 36 5.1 " " " " " "
Zinc 39 7.0 " " " " " "

Page 2 of 12 ends

Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/13/21 12:23
1905 E 21st St. - Spud Field
Metals by EPA 6000/7000 Series Methods
Sierra Analytical Labs, Inc.

Analyte Result Limit
Reporting
Units Dilution Batch Prepared Analyzed Method Notes
SB3-5 (2107058-03) Soil Sampled: 07/06/21 08:01 Received: 07/06/21 14:35 Silver ND 2.0 mg/kg 1 B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Arsenic ND 5.5 " " " " " "
Barium 48 6.0 " " " " " "
Beryllium ND 2.2 " " " " " "
Cadmium ND 2.5 " " " " " "
Cobalt 4.6 3.3 " " " " " "
Chromium 9.0 2.3 " " " " " "
Hexavalent Chromium ND 0.10 " " B1G0711 07/07/21 07/09/21 12:47 EPA 7199A Copper 16 5.0 " " B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Mercury ND 0.90 " " B1G0613 07/06/21 07/06/21 20:35 EPA 7471A Molybdenum ND 5.2 " " B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Nickel 6.2 3.0 " " " " " "
Lead ND 7.1 " " " " " "
Antimony ND 8.0 " " " " " "
Selenium ND 6.9 " " " " " "
Thallium ND 17 " " " " " "
Vanadium 16 5.1 " " " " " "
Zinc 29 7.0 " " " " " "
SB4-5 (2107058-04) Soil Sampled: 07/06/21 08:08 Received: 07/06/21 14:35 Silver ND 2.0 mg/kg 1 B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Arsenic ND 5.5 " " " " " "
Barium 170 6.0 " " " " " "
Beryllium ND 2.2 " " " " " "
Cadmium ND 2.5 " " " " " "
Cobalt 14 3.3 " " " " " "
Chromium 42 2.3 " " " " " "
Hexavalent Chromium ND 0.10 " " B1G0711 07/07/21 07/09/21 12:47 EPA 7199A Copper 45 5.0 " " B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Mercury ND 0.90 " " B1G0613 07/06/21 07/06/21 20:35 EPA 7471A Molybdenum ND 5.2 " " B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Nickel 26 3.0 " " " " " "
Lead 9.5 7.1 " " " " " "
Antimony ND 8.0 " " " " " "
Selenium ND 6.9 " " " " " "
Thallium ND 17 " " " " " "
Vanadium 58 5.1 " " " " " "
Zinc 74 7.0 " " " " " "

Page 3 of 12 ends

Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/13/21 12:23
1905 E 21st St. - Spud Field
Metals by EPA 6000/7000 Series Methods
Sierra Analytical Labs, Inc.

Analyte Result Limit
Reporting
Units Dilution Batch Prepared Analyzed Method Notes
SB5-5 (2107058-05) Soil Sampled: 07/06/21 08:16 Received: 07/06/21 14:35 Silver ND 2.0 mg/kg 1 B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Arsenic ND 5.5 " " " " " "
Barium 97 6.0 " " " " " "
Beryllium ND 2.2 " " " " " "
Cadmium ND 2.5 " " " " " "
Cobalt 16 3.3 " " " " " "
Chromium 30 2.3 " " " " " "
Hexavalent Chromium ND 0.10 " " B1G0711 07/07/21 07/09/21 12:47 EPA 7199A Copper 40 5.0 " " B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Mercury ND 0.90 " " B1G0613 07/06/21 07/06/21 20:35 EPA 7471A Molybdenum ND 5.2 " " B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Nickel 27 3.0 " " " " " "
Lead 8.5 7.1 " " " " " "
Antimony ND 8.0 " " " " " "
Selenium ND 6.9 " " " " " "
Thallium ND 17 " " " " " "
Vanadium 52 5.1 " " " " " "
Zinc 56 7.0 " " " " " "
SB6-5 (2107058-06) Soil Sampled: 07/06/21 08:23 Received: 07/06/21 14:35 Silver ND 2.0 mg/kg 1 B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Arsenic ND 5.5 " " " " " "
Barium 130 6.0 " " " " " "
Beryllium ND 2.2 " " " " " "
Cadmium ND 2.5 " " " " " "
Cobalt 22 3.3 " " " " " "
Chromium 42 2.3 " " " " " "
Hexavalent Chromium ND 0.10 " " B1G0711 07/07/21 07/09/21 12:47 EPA 7199A Copper 46 5.0 " " B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Mercury ND 0.90 " " B1G0613 07/06/21 07/06/21 20:35 EPA 7471A Molybdenum ND 5.2 " " B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Nickel 33 3.0 " " " " " "
Lead 11 7.1 " " " " " "
Antimony ND 8.0 " " " " " "
Selenium ND 6.9 " " " " " "
Thallium ND 17 " " " " " "
Vanadium 71 5.1 " " " " " "
Zinc 85 7.0 " " " " " "

Page 4 of 12 ends

Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/13/21 12:23
1905 E 21st St. - Spud Field
Metals by EPA 6000/7000 Series Methods
Sierra Analytical Labs, Inc.

Analyte Result Limit
Reporting
Units Dilution Batch Prepared Analyzed Method Notes
SB7-5 (2107058-07) Soil Sampled: 07/06/21 08:31 Received: 07/06/21 14:35 Silver ND 2.0 mg/kg 1 B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Arsenic ND 5.5 " " " " " "
Barium 80 6.0 " " " " " "
Beryllium ND 2.2 " " " " " "
Cadmium ND 2.5 " " " " " "
Cobalt 12 3.3 " " " " " "
Chromium 24 2.3 " " " " " "
Hexavalent Chromium ND 0.10 " " B1G0711 07/07/21 07/09/21 12:47 EPA 7199A Copper 26 5.0 " " B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Mercury ND 0.90 " " B1G0613 07/06/21 07/06/21 20:35 EPA 7471A Molybdenum ND 5.2 " " B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Nickel 19 3.0 " " " " " "
Lead ND 7.1 " " " " " "
Antimony ND 8.0 " " " " " "
Selenium ND 6.9 " " " " " "
Thallium ND 17 " " " " " "
Vanadium 43 5.1 " " " " " "
Zinc 47 7.0 " " " " " "
SB8-5 (2107058-08) Soil Sampled: 07/06/21 08:38 Received: 07/06/21 14:35 Silver ND 2.0 mg/kg 1 B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Arsenic ND 5.5 " " " " " "
Barium 180 6.0 " " " " " "
Beryllium ND 2.2 " " " " " "
Cadmium ND 2.5 " " " " " "
Cobalt 17 3.3 " " " " " "
Chromium 38 2.3 " " " " " "
Hexavalent Chromium ND 0.10 " " B1G0711 07/07/21 07/09/21 12:47 EPA 7199A Copper 37 5.0 " " B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Mercury ND 0.90 " " B1G0613 07/06/21 07/06/21 20:35 EPA 7471A Molybdenum ND 5.2 " " B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Nickel 32 3.0 " " " " " "
Lead 11 7.1 " " " " " "
Antimony ND 8.0 " " " " " "
Selenium ND 6.9 " " " " " "
Thallium ND 17 " " " " " "
Vanadium 68 5.1 " " " " " "
Zinc 51 7.0 " " " " " "

Page 5 of 12 ends

Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/13/21 12:23
1905 E 21st St. - Spud Field
Metals by EPA 6000/7000 Series Methods
Sierra Analytical Labs, Inc.

Analyte Result Limit
Reporting
Units Dilution Batch Prepared Analyzed Method Notes
SB9-5 (2107058-09) Soil Sampled: 07/06/21 08:47 Received: 07/06/21 14:35 Silver ND 2.0 mg/kg 1 B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Arsenic ND 5.5 " " " " " "
Barium 87 6.0 " " " " " "
Beryllium ND 2.2 " " " " " "
Cadmium ND 2.5 " " " " " "
Cobalt 14 3.3 " " " " " "
Chromium 30 2.3 " " " " " "
Hexavalent Chromium ND 0.10 " " B1G0711 07/07/21 07/09/21 12:47 EPA 7199A Copper 28 5.0 " " B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Mercury ND 0.90 " " B1G0613 07/06/21 07/06/21 20:35 EPA 7471A Molybdenum ND 5.2 " " B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Nickel 24 3.0 " " " " " "
Lead 9.0 7.1 " " " " " "
Antimony ND 8.0 " " " " " "
Selenium ND 6.9 " " " " " "
Thallium ND 17 " " " " " "
Vanadium 54 5.1 " " " " " "
Zinc 38 7.0 " " " " " "
SB10-5 (2107058-10) Soil Sampled: 07/06/21 08:58 Received: 07/06/21 14:35 Silver ND 2.0 mg/kg 1 B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Arsenic ND 5.5 " " " " " "
Barium 98 6.0 " " " " " "
Beryllium ND 2.2 " " " " " "
Cadmium ND 2.5 " " " " " "
Cobalt 13 3.3 " " " " " "
Chromium 27 2.3 " " " " " "
Hexavalent Chromium ND 0.10 " " B1G0711 07/07/21 07/09/21 12:47 EPA 7199A Copper 30 5.0 " " B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Mercury ND 0.90 " " B1G0613 07/06/21 07/06/21 20:35 EPA 7471A Molybdenum ND 5.2 " " B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Nickel 23 3.0 " " " " " "
Lead 7.5 7.1 " " " " " "
Antimony ND 8.0 " " " " " "
Selenium ND 6.9 " " " " " "
Thallium ND 17 " " " " " "
Vanadium 51 5.1 " " " " " "
Zinc 39 7.0 " " " " " "

Page 6 of 12 ends

Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/13/21 12:23
1905 E 21st St. - Spud Field
Metals by EPA 6000/7000 Series Methods
Sierra Analytical Labs, Inc.

Analyte Result Limit
Reporting
Units Dilution Batch Prepared Analyzed Method Notes
SB11-5 (2107058-11) Soil Sampled: 07/06/21 09:10 Received: 07/06/21 14:35 Silver ND 2.0 mg/kg 1 B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Arsenic ND 5.5 " " " " " "
Barium 120 6.0 " " " " " "
Beryllium ND 2.2 " " " " " "
Cadmium ND 2.5 " " " " " "
Cobalt 9.8 3.3 " " " " " "
Chromium 22 2.3 " " " " " "
Hexavalent Chromium ND 0.10 " " B1G0711 07/07/21 07/09/21 12:47 EPA 7199A Copper 14 5.0 " " B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Mercury ND 0.90 " " B1G0613 07/06/21 07/06/21 20:35 EPA 7471A Molybdenum ND 5.2 " " B1G0611 07/06/21 07/07/21 13:55 EPA 6010B Nickel 16 3.0 " " " " " "
Lead ND 7.1 " " " " " "
Antimony ND 8.0 " " " " " "
Selenium ND 6.9 " " " " " "
Thallium ND 17 " " " " " "
Vanadium 39 5.1 " " " " " "
Zinc 31 7.0 " " " " " "

Page 7 of 12 ends

Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/13/21 12:23
1905 E 21st St. - Spud Field
Result Limit
Reporting
Units Level
Spike
Result
Source
%REC
%REC
Limits RPD
RPD
Analyte Limit Notes
Metals by EPA 6000/7000 Series Methods - Quality Control Sierra Analytical Labs, Inc.

Batch B1G0611 - EPA 3050B
Blank (B1G0611-BLK1) Prepared: 07/06/21 Analyzed: 07/07/21 Antimony ND 8.0 mg/kg
Selenium ND 6.9 "
Cadmium ND 2.5 "
Vanadium ND 5.1 "
Chromium ND 2.3 "
Cobalt ND 3.3 "
Zinc ND 7.0 "
Thallium ND 17 "
Copper ND 5.0 "
Barium ND 6.0 "
Lead ND 7.1 "
Arsenic ND 5.5 "
Molybdenum ND 5.2 "
Nickel ND 3.0 "
Silver ND 2.0 "
Beryllium ND 2.2 "
LCS (B1G0611-BS1) Prepared: 07/06/21 Analyzed: 07/07/21 Copper 107 5.0 mg/kg 100 107 78-122
Lead 112 7.1 " 100 112 80-120
Antimony 103 8.0 " 100 103 75-125
Chromium 111 2.3 " 100 111 80-120
Selenium 105 6.9 " 100 105 76-124
Cobalt 119 3.3 " 100 119 80-120
Beryllium 107 2.2 " 100 107 80-120
Silver 106 2.0 " 100 106 60-140
Arsenic 105 5.5 " 100 105 78-122
Barium 112 6.0 " 100 112 80-120
Zinc 110 7.0 " 100 110 80-120
Nickel 119 3.0 " 100 119 80-120
Vanadium 107 5.1 " 100 107 80-120
Cadmium 103 2.5 " 100 103 80-120
Molybdenum 108 5.2 " 100 108 80-120
Thallium 114 17 " 100 114 80-120

Page 8 of 12 ends

Project Number:

Project Manager:

Reported:

Batch B1G0611 - EPA 3050B
LCS Dup (B1G0611-BSD1) Prepared: 07/06/21 Analyzed: 07/07/21 Beryllium 105 2.2 mg/kg 100 105 80-120 1.49 20
Chromium 106 2.3 " 100 106 80-120 4.14 20
Cadmium 97.5 2.5 " 100 97.5 80-120 5.78 20
Copper 112 5.0 " 100 112 78-122 4.64 20
Arsenic 101 5.5 " 100 101 78-122 3.70 20
Cobalt 116 3.3 " 100 116 80-120 2.58 20
Silver 108 2.0 " 100 108 60-140 1.96 40
Molybdenum 105 5.2 " 100 105 80-120 3.50 20
Barium 109 6.0 " 100 109 80-120 2.55 20
Vanadium 105 5.1 " 100 105 80-120 1.32 20
Selenium 100 6.9 " 100 100 76-124 4.29 20
Antimony 112 8.0 " 100 112 75-125 8.57 20
Nickel 115 3.0 " 100 115 80-120 3.21 20
Lead 115 7.1 " 100 115 80-120 3.08 20
Thallium 107 17 " 100 107 80-120 6.02 20
Zinc 109 7.0 " 100 109 80-120 1.23 20
Matrix Spike (B1G0611-MS1) Source: 2107028-01 Prepared: 07/06/21 Analyzed: 07/07/21 Vanadium 126 5.1 mg/kg 96.8 32.6 96.9 70-130
Barium 192 6.0 " 96.8 83.1 113 70-130
Cobalt 102 3.3 " 96.8 7.94 97.4 70-130
Molybdenum 82.1 5.2 " 96.8 0.635 84.2 70-130
Cadmium 84.1 2.5 " 96.8 1.03 85.8 70-130
Zinc 132 7.0 " 96.8 46.6 88.5 70-130
Arsenic 86.3 5.5 " 96.8 ND 89.2 70-130
Selenium 86.0 6.9 " 96.8 1.66 87.2 70-130
Silver 99.9 2.0 " 96.8 0.269 103 60-140
Beryllium 88.1 2.2 " 96.8 0.220 91.1 70-130
Antimony 94.6 8.0 " 96.8 5.77 91.8 60-140
Chromium 109 2.3 " 96.8 17.4 94.5 70-130
Nickel 110 3.0 " 96.8 15.2 97.7 70-130
Thallium 85.0 17 " 96.8 ND 87.8 70-130
Lead 129 7.1 " 96.8 22.8 109 70-130
Copper 135 5.0 " 96.8 25.5 113 70-130

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Project Number:

Project Manager:

Reported:

Batch B1G0611 - EPA 3050B
Matrix Spike Dup (B1G0611-MSD1) Source: 2107028-01 Prepared: 07/06/21 Analyzed: 07/07/21 Barium 193 6.0 mg/kg 96.7 83.1 114 70-130 0.455 20
Molybdenum 82.3 5.2 " 96.7 0.635 84.4 70-130 0.168 20
Silver 98.4 2.0 " 96.7 0.269 101 60-140 1.49 40
Arsenic 87.1 5.5 " 96.7 ND 90.0 70-130 0.880 20
Zinc 148 7.0 " 96.7 46.6 105 70-130 11.0 20
Nickel 107 3.0 " 96.7 15.2 95.2 70-130 2.37 20
Cobalt 103 3.3 " 96.7 7.94 98.1 70-130 0.588 20
Copper 136 5.0 " 96.7 25.5 115 70-130 1.31 30
Beryllium 87.0 2.2 " 96.7 0.220 90.0 70-130 1.31 20
Thallium 85.1 17 " 96.7 ND 88.0 70-130 0.102 20
Lead 127 7.1 " 96.7 22.8 108 70-130 1.16 30
Chromium 110 2.3 " 96.7 17.4 95.8 70-130 1.07 20
Cadmium 86.2 2.5 " 96.7 1.03 88.1 70-130 2.52 20
Vanadium 124 5.1 " 96.7 32.6 94.2 70-130 2.17 20
Antimony 91.9 8.0 " 96.7 5.77 89.1 60-140 2.90 20
Selenium 87.0 6.9 " 96.7 1.66 88.3 70-130 1.16 20
Batch B1G0613 - EPA 7471A
Blank (B1G0613-BLK1) Prepared & Analyzed: 07/06/21
Mercury ND 0.90 mg/kg
LCS (B1G0613-BS1) Prepared & Analyzed: 07/06/21
Mercury 0.20 0.90 mg/kg 0.167 118 70-130
Matrix Spike (B1G0613-MS1) Source: 2107028-01 Prepared & Analyzed: 07/06/21 Mercury 0.24 0.90 mg/kg 0.163 0.09 90.8 70-130

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Project Number:

Project Manager:

Reported:

Batch B1G0613 - EPA 7471A
Matrix Spike Dup (B1G0613-MSD1) Source: 2107028-01 Prepared & Analyzed: 07/06/21 Mercury 0.24 0.90 mg/kg 0.162 0.09 89.1 70-130 1.57 30
Batch B1G0711 - EPA 3060A
Blank (B1G0711-BLK1) Prepared: 07/07/21 Analyzed: 07/09/21 Hexavalent Chromium ND 0.10 mg/kg
LCS (B1G0711-BS1) Prepared: 07/07/21 Analyzed: 07/09/21 Hexavalent Chromium 0.158 0.10 mg/kg 0.150 105 80-120
Matrix Spike (B1G0711-MS1) Source: 2107058-01 Prepared: 07/07/21 Analyzed: 07/09/21 Hexavalent Chromium 0.175 0.10 mg/kg 0.149 0.0273 99.1 75-125 Matrix Spike Dup (B1G0711-MSD1) Source: 2107058-01 Prepared: 07/07/21 Analyzed: 07/09/21 Hexavalent Chromium 0.183 0.10 mg/kg 0.150 0.0273 104 75-125 4.44 20

Page 11 of 12 ends

Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/13/21 12:23
1905 E 21st St. - Spud Field
Notes and Definitions
Sample results reported on a dry weight basis
RPD Relative Percent Difference
dry
NR Not Reported
ND Analyte NOT DETECTED at or above the reporting limit DET Analyte DETECTED

Page 12 of 12 ends

F11b
Human Health Risk Assessment, Town Center Northwest
Human Health Risk Assessment
Northeast Corner E Willow St. and Walnut Avenue
Town Center Northwest
Signal Hill, California 90755
August 11, 2021
Prepared for:

City of Signal Hill
2175 Cherry Avenue
Signal Hill, California 90755
Prepared by:

Mearns Consulting LLC
738 Ashland Avenue
Santa Monica, California 90405

MEARNS CONSULTING LLC ENVIRONMENTAL CONSULTANTS

RISK ASSESSORS
738 Ashland Avenue, Santa Monica, California 90405
Cell 310.403.1921
Tel 310.396.9606 Fax310.396.6878
[email protected]
www.MearnsConsulting.com
1 August 11, 2021
via email
Ms. Elise McCaleb, Economic Development and Redevelopment Manager Ms. Colleen Doan, Community Development Director
City of Signal Hill
2175 Cherry Avenue
Signal Hill, Ca 90755
RE: Human Health Risk Assessment
Northeast Corner E Willow St., and Walnut Avenue, Town Center Northwest, Signal Hill, California 90755 Dear Ms. McCaleb and Ms. Doan:

I am pleased to present this Human Health Risk Assessment (HHRA) for the 8.35–acre site located at the northeast corner of the intersection of East Willow Street and Walnut Avenue, known as Town Center Northwest, in Signal Hill, Los Angeles County, California 90755 (the site) pursuant to the contract executed on November 12, 2020.

The historical use of the site is an oil field. Ten previously abandoned oil wells, associated piping runs, historic aboveground storage tanks and oil well sumps are located onsite in addition to operating units, idle units, pipelines and a stormwater drainage system with swales. The Signal Hill Petroleum, Inc. Drill Site located in the northeast portion of the site is not a part of the project.

The objectives of this baseline human health risk assessment are to evaluate potential health risks to human receptors posed by concentrations of constituents detected at least one time in the soil matrix and soil vapor underlying the 8.35-acre property, and (2) to determine mitigation measures protective of human health for the proposed residential development.

Environmental Protection Agency Risk Assessment Guidance for Superfund volume 1, Human Health Evaluation Manual (Part F, Supplemental Guidance for Inhalation Risk Assessment) (USEPA 2009), the DTSC Guidance for the Evaluation and Mitigation of Subsurface Vapor Intrusion to Indoor Air (DTSC, October 2011), the DRAFT DTSC Supplemental Guidance:

Screening and Evaluating Vapor Intrusion (DTSC, February 2020), the San Francisco Bay Regional Water Quality Control Board (SFRWQCB) Environmental Screening Levels (ESL) model and the Virginia Department of Environmental Quality Virginia Unified Risk Assessment Model (VURAM).

The results of the human health risk assessment indicate the summed risk of the carcinogenic constituents did exceed the target threshold of 1x10-6 for the residential occupants and did exceed the target threshold of 1x10-5 for commercial workers. However, the estimated risks for commercial workers are between 10-6 and one in 10,000 (10-4) which are "safe and protective of public health" (Federal Register 56(20):3535, 1991) within a risk range acceptable to DTSC (February 2020).

The estimated risk for the construction worker scenario did not exceed the target threshold of 1x10-5.

The results of the human health risk assessment indicate that the estimated summed hazard index of the noncarcinogenic constituents did exceed the target hazard threshold of 1 for the residential occupants and the commercial worker and construction worker scenarios.

MEARNS CONSULTING LLC ENVIRONMENTAL CONSULTANTS

RISK ASSESSORS
738 Ashland Avenue, Santa Monica, California 90405
Cell 310.403.1921
Tel 310.396.9606 Fax 310.396.6878
[email protected]
www.MearnsConsulting.com
Ms. McCaleb and Ms. Doan
Human Health Risk Assessment – Town Center Northwest, Signal Hill, California 90755 August 11, 2021
2 Mearns Consulting LLC
Conclusions and Recommendations
A potential future use of the site is multi-family residential. The residual concentrations of benzene, ethylbenzene, methyl tertbutyl ether, naphthalene, tetrachloroethene and gasoline range organics detected in the soil vapor and C13-C22 in the soil matrix poses an adverse impact to future residential occupants. The residual concentration of benzene, ethylbenzene, methyl tert-butyl ether, naphthalene and gasoline range organics in the soil vapor poses an adverse impact to commercial workers. The residual concentration of gasoline range organics in the soil vapor poses an adverse impact to construction workers.

The previously abandoned oil wells should be located, daylighted and methane gas leak tested prior to the installation of vent cones and vent risers pursuant to the City of Signal Hill’s Oil and Gas Code §16.24.030 and §16.24.040.

Institutional controls, i.e., a methane mitigation system to be installed subslab of any proposed buildings, pursuant to the City of Signal Hill’s Oil and Gas Code §16.24.080 will effectively mitigate risks and hazards due to vapor intrusion to negligible conditions ensuring the site is safe for any future intended use including as a residential property. A redeveloped property precludes exposure to site soils by future residential occupants.

A soil management plan should be prepared prior to any grading activities to be conducted onsite. This soil management plan should provide instructions for the contractor to implement in the event discolored or odiferous soils are discovered during any grading operations. A R1166 permit should be obtained from the AQMD due to the presence of volatiles onsite prior to the start of grading operations.

Additionally construction workers are advised to practice good hygiene and wash their hands prior to smoking or eating or drinking pursuant to 29CFR 1926.1910, 8CCR 4 and 22CCR 2.4 to mitigate contact with soils containing residual concentrations of carbon chains.

Should you have any questions or desire additional information, please contact me at your earliest convenience at 310.403.1921.

Sincerely,
X
Susan L. Mearns, Ph.D.

Mearns Consulting LLC

HUMAN HEALTH RISK ASSESSMENT
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TABLE OF CONTENTS
EXECUTIVE SUMMARY ........................................................................................... 1

1.0 INTRODUCTION ......................................................................................................... 3

2.0 SITE BACKGROUND ................................................................................................. 4

3.0 SUMMARY OF FIELD ACTIVITIES ......................................................................... 6

3.1 Site Geology ........................................................................................................... 7

3.2 Soil Matrix Analytical Results ............................................................................... 7

3.3 Soil Vapor Anlytical Results .................................................................................. 8

3.4 Conclusions and Recommendations ....................................................................... 8

4.0 CONCEPTUAL SITE MODEL .................................................................................... 9

5.0 IDENTIFYING CHEMICALS OF CONCERN .......................................................... 10

6.0 TOXICITY ASSESSMENT ........................................................................................ 11

7.0 EXPOSURE ASSESSMENT ...................................................................................... 12

7.1 Average and Reasonable Maximum Exposures ................................................... 12

8.0 RISK CHARACTERIZATION ................................................................................... 13

8.1 Ingestion and Dermal Contact Exposure Pathways .............................................. 13

8.2 Inhalation Pathway Soil Matrix ............................................................................ 14

8.3 SFRWQCB ESL Model ........................................................................................ 15

8.4 VURAM Model .................................................................................................... 15

8.5 Noncancer Adverse Health Effects ....................................................................... 16

8.6 Lifetime Excess Cancer Risk ................................................................................ 16

8.7 Multipathway Cancer Risk ................................................................................... 16

8.8 Estimation of Risks and Hazards .......................................................................... 17

9.0 MITIGATION MEASURES ....................................................................................... 20

10.0 UNCERTAINTY ANALYSIS .................................................................................. 21

10.1 Data Collection and Evaluation .......................................................................... 21

10.2 Exposure Assessment ......................................................................................... 21

10.2.1 Exposure Pathways ......................................................................................... 21

10.3 Toxicity Assessment ........................................................................................... 22

10.4 Risk Characterization.......................................................................................... 22

10.5 Summary of Risk Assessment Uncertainties ..................................................... 22

11.0 REFERENCES .......................................................................................................... 23

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TABLES
Table 1 - TPH and Metals Analytical Results in Soil Matrix Table 2 - Background Metals Analytical Results in Soil Matrix Table 3 - VOCs Analytical Results in Soil Matrix
Table 4 - SVOCs Analytical Results in Soil Matrix
Table 5 - Soil Vapor Analytical Results
Table 6 - EPCs, Slope Factors, Reference Doses
Table 7 - Exposure Parameters
Table 8 - Estimated Risks and Hazards - Residential Scenario Table 9 - Estimated Risks and Hazards - Commercial Scenario Table 10 - Estimated Risks and Hazards - Construction Scenario Table 11 - Summed Estimated Risks and Hazards

FIGURES
Figure 1 - Site Location
Figure 2 - Site Map
Figure 3 - Oil Wells: Active, Idle and Previously Abandoned Figure 4 - Concentrations of Metals and Carbon Chains that Exceed Thresholds Figure 5 - Detected Concentrations of VOCs and SVOCs in Soil Figure 6 - Soil Vapor Analytical Results
Figure 7 - Conceptual Site Model

APPENDICES
Appendix A - Sierra Analytical Labs, Inc. July 12 & 13, 2021 Soil Matrix Analytical Data Appendix B - Jones Environmental, Inc. July 27 & 28, 2021 Soil Vapor Data Appendix C - Sierra Analytical Labs, Inc. April 2005 & July 2021 Background Metals Analytical Data
Appendix D- Boring Logs
Appendix E - Metals Statistical Analyses
Appendix F - ProUCL Statistical Analyses
Appendix G - ESL Model Results Soil Vapor - Residential Appendix H - ESL Model Results Soil Vapor - Commercial
Appendix I - VURAM
Appendix J - LeadSpread

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EXECUTIVE SUMMARY
The 8.35–acre site located at the northeast corner of the intersection of East Willow Street and Walnut Avenue, is known as Town Center Northwest, in Signal Hill, Los Angeles County, California 90755.

The objectives of this HHRA are: (1) to evaluate potential health risks to human receptors posed by concentrations of constituents detected at least one time in the soil matrix and soil vapor underlying the

8.35-acre property, and (2) to determine mitigation measures protective of human health for the proposed residential/commercial development.

This baseline human health risk assessment followed the guidance in the Department of Toxic Substances Control (DTSC) Preliminary Endangerment Assessment (PEA) guidance manual (DTSC 2015), U.S. Environmental Protection Agency Risk Assessment Guidance for Superfund volume 1, Human Health Evaluation Manual (RAGs) (USEPA 2004), the U.S. Environmental Protection Agency Risk Assessment Guidance for Superfund volume 1, Human Health Evaluation Manual (Part F, Supplemental Guidance for Inhalation Risk Assessment) (USEPA 2009), the DTSC Guidance for the Evaluation and Mitigation of Subsurface Vapor Intrusion to Indoor Air (DTSC, October 2011), the DRAFT DTSC Supplemental Guidance: Screening and Evaluating Vapor Intrusion (DTSC, February 2020), the San Francisco Bay Regional Water Quality Control Board (SFRWQCB) Environmental Screening Levels (ESL) model and the Virginia Department of Environmental Quality Virginia Unified Risk Assessment Model (VURAM).

The site is being considered as a multi-family residential redevelopment.

The results of the human health risk assessment indicate the summed risk of the carcinogenic constituents exceeded the target threshold of 1x10-6 for the residential occupants and exceeded the target threshold of 1x10-5 for the commercial worker scenario. However these estimated risks are between 10-6 and one in 10,000 (10-4) which are "safe and protective of public health" (Federal Register 56(20):3535, 1991) and within a risk range acceptable to DTSC (February 2020).

The results of the human health risk assessment indicate that the estimated summed hazard index of the noncarcinogenic constituents exceeded the target hazard threshold of 1 for the residential occupants, the commercial worker and construction worker scenarios.

The estimated risk for the construction worker scenario did not exceed the target threshold of 1x10-5.

A methane assessment of the 8.35-acre site was performed in July 2021 in accordance with the City of Signal Hill Oil and Gas Code §16.24.080, City of Signal Hill Project Development Guide (June 20, 2017), the Los Angeles Department of Building and Safety (LADBS) published, Site Testing Standards for Methane (Reference No. 91.7104.1, Document No. P/BC 2002- 101), effective 11/30/04, and the DTSC Methane Advisories (2005 and 2012). Methane was consistently detected in the field at concentrations as great as 861,000 parts per million by volume (ppmv) in soil vapor probes at 5-ft, 10-ft and 20-ft bgs.

Methane was detected in seven of eight soil vapor samples collected from 10-ft and 20-ft bgs and submitted to the Eurofins stationary laboratory at concentrations of 1.5 ppmv, 3,000 ppmv, 2 ppmv, 8,200 ppmv, 11,000 ppmv, 17,000 ppmv and 74,000 ppmv.

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Methane mitigation subslab of proposed buildings is recommended (DL Science, Inc. July 15, 2021). The methane mitigation system should consist of a subslab impervious membrane placed inbetween geotextile or geocloth to protect it from sand above and the 4” thick gravel blanket below in conformance with the City of Signal Hill Oil and Gas Code §16.24.080 and City of Signal Hill Project Development Guide (June 20, 2017). Perforated horizontal vent pipes should be placed in the 4” thick gravel blanket and tied into vertical vent risers (typically cast iron) placed inbetween the interior and exterior walls, less than 100-feet apart, extending a minimum of 3-feet above the roof line and should not terminate less than 100- feet from any opening (City of Signal Hill June 2020).

Although designed to capture and vent methane to the atmosphere, other volatile organic compounds (VOCs) in the subsurface (both in the soil matrix and soil vapor) also will be captured and vented by this system.

Conclusions and Recommendations – A potential future use of the site is residential. The residual concentrations of benzene, ethylbenzene, methyl tert-butyl ether, naphthalene, tetrachloroethene and gasoline range organics detected in the soil vapor and naphthalene, 2,6-dinitrotoluene, 4-nitrosodi-npropylamine and carbon chains C13-C22 in the soil matrix poses an adverse impact to future residential occupants. The residual concentration of benzene, ethylbenzene, methyl tert-butyl ether, naphthalene and gasoline range organics in the soil vapor poses an adverse impact to commercial workers. The residual concentration of gasoline range organics in the soil vapor poses an adverse impact to construction workers.

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1.0 INTRODUCTION
This report presents the results of a baseline Human Health Risk Assessment (HHRA) for 8.35–acre site located at the northeast corner of the intersection of East Willow Street and Walnut Avenue, known as Town Center Northwest, in Signal Hill, Los Angeles County, California 90755 (the site) (Figures 1 and 2).

The purpose of this human health risk assessment is to evaluate the potential adverse health impacts due to exposure to concentrations of constituents detected in the soil matrix and soil vapor underlying the site. If a constituent was detected one time in soil sampled at 5-ft, 10-ft, 15-ft, or the boring terminus, and/or one time in soil vapor at 5-ft or 15-ft bgs it was retained and quantitatively assessed in this human health risk assessment.

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2.0 SITE BACKGROUND
The 8.35-acre site has been and is an oil field since at least 1928. Historically, the site had oil derricks, sumps and aboveground storage tanks.

The site is bounded by East Willow street on the south and Walnut Avenue on the west, located at the northeast corner of the intersection of East Willow Street and Walnut Avenue and known as Town Center Northwest in Signal Hill, California 90755 (Figures 1 and 2). The latitude of the site is 33o 48’

19.13” north and the longitude is 118o 10’ 15.02” west. The Los Angeles County Assessor’s Parcel Number for the site is 7212-011-034.

Pursuant to the authorization of Ms. Colleen Doan (Community Development Director, City of Signal Hill) on November 12, 2020 and to comply with the City of Signal Hill Project Development Guide (2020) Mearns Consulting LLC performed a Phase I Environmental Site Assessment (Phase I ESA) for the site in May 2021.

The Phase I ESA had the following conclusions:
• The historical use of the site is an oil field. There are 34 oil wells onsite or contiguous to the site (19 onsite and 15 within the eastern two-thirds of the Drill Site which is not a part of the project site). Operating units, a stormwater system with detention basins, swales, berms and piping currently are onsite.
• Recognized Environmental Conditions onsite include: (1) the previously abandoned oil wells, (2) the historic aboveground storage tanks, (3) historic pipelines associated with the previously abandoned oil wells and/or the aboveground storage tanks, (4) historic sumps associated with the previously abandoned and/or operating oil wells, (5) the storage of 55-gallon containers of used oil, (6) retail-sized containers of motor oil, (7) 5-gallon buckets of oil, (8) residue in catch basins, (9) gasoline containers, (10) surface staining, (11) transformers, (12) forklifts and (13) the northeastern corner drainage are Recognized Environmental Conditions. • The adjacent properties include commercial/industrial businesses, an oilfield and multifamily residences. The adjacent oilfield and operating units are Potential Recognized Environmental Conditions that may impact the site. The contiguous former Dico Oil Company property with a LURA designation from DTSC also is a Potential Recognized Environmental Condition that may impact the site.
• The adjacent properties include oilfields, operating units and commercial/industrial businesses.

The adjacent oilfields and operating units are Potential Recognized Environmental Conditions that may impact the site.

The Phase I ESA had the following recommendations:

Pursuant to the City of Signal Hill Project Development Guide (2020) and the City of Signal Hill Oil and Gas Code (2015) a Phase II Environmental Site Assessment (Phase II ESA) should be performed. The Phase II ESA should include soil matrix and soil vapor sampling adjacent to the previously abandoned oil wells, the historic location of the aboveground storage tanks, and within the footprint of the proposed multifamily units.

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A baseline human health risk assessment should be performed with the data generated from the Phase II ESA.

A methane assessment should be performed in accordance with the City of Signal Hill Oil and Gas Code §16.24.080.

The previously abandoned oil wells should be daylighted and leak tested pursuant to the City of Signal Hill Oil and Gas Code §16.24.030 and §16.24.040
Piping runs should be identified and removed.

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3.0 SUMMARY OF FIELD ACTIVITIES
Phase II Environmental Site Assessment - Soil samples were collected at 5-ft, 10-ft and 15-ft bgs from 19 locations (Figure 4) in accordance with SW846. A truck mounted direct push rig was used to collect the soil samples. The sampling system was appropriately cleaned between each borehole; rinsate from cleaning was appropriately disposed. Soil was collected in acetate sleeves with Teflon liners and end caps with minimal headspace.

Fifty-six soil samples were logged onto a chain-of-custody form and stored in a cooler at 4o C until
delivered to Sierra Analytical Labs, Inc. (a State of California Department of Health Services [DOHS] ELAP accredited laboratory; ELAP No. 2320). Analyses requested were carbon chain ranges C4-C12, C13-C23, C23-C40 via USEPA method GC/FID 8015B, total threshold limit concentration (TTLC) metals and hexavalent chromium via USEPA methods 6010B/7471, volatile organic compounds via USEPA 8260B, collected via USEPA 5035B in the field by placing 5g of soil into volatile organic analyte vials to which preservative had been added and semi-volatile organic compounds via USEPA 8270C. Soil matrix analytical results are included as Appendix A.

These soil borings were then developed as dual-nested soil vapor probes at 5-feet and 15-feet bgs (SV1- SV19) in accordance with Final Guidance for the Evaluation and Mitigation of Subsurface Vapor Intrusion to Indoor Air (Vapor Intrusion Guidance), DTSC, October 2011, the Advisory Active Soil Gas Investigations, DTSC, LARWQCB, SFRWQCB, July 2015 and the DRAFT Supplemental Guidance Screening and Evaluating Vapor Intrusion (CalEPA, DTSC, SWRCB February 2020).

A new section of ¼-inch diameter nylaflow tubing with a new 6-inch stainless steel probe tip at the terminal end was inserted into the borehole to the desired sampling depth. One-inch diameter polyvinyl chloride (PVC) casing was used as a guide for the tubing to ensure that the desired sampling depth was achieved. Sand was poured into the boring annulus to form an approximately one-foot long sand pack around the probe tip, at which time the PVC piping was withdrawn. Approximately one foot of dry, granular bentonite was placed atop the sand pack and the remainder of the borehole was backfilled with hydrated bentonite to the ground surface to form a seal. The sampling end of the tubing was fitted with a three-way valve and the probe was labeled for identification.

Soil gas samples were collected in general accordance with the July 2015 DTSC and LARWQCB) “Advisory – Active Soil Gas Investigations.”
Each probe was allowed to equilibrate for a minimum of 48-hours after installation prior to sampling by a mobile laboratory. Soil vapor samples were collected in glass gas-tight syringes equipped with Teflon plungers. A tracer gas mixture of n-pentane, n-hexane, and n-heptane was placed at the tubing-surface interface before sampling. These compounds were analyzed during the 8260B analytical run to determine if there were surface leaks into the subsurface due to improper installation of the probe. The sampling rate was approximately 200 cc/min, except when noted differently on the chain of custody record, using a glass gas-tight syringe. Purging was completed using a pump set at approximately 200 cc/min, except when noted differently on the chain of custody record. A default of three purge volumes was used as recommended by July 2015 DTSC/RWQCB guidance documents. Prior to purging and sampling of soil vapor at each location, a shut-in test was conducted to check for leaks in the aboveground fittings. The shut-in test was performed on the aboveground apparatus by evacuating the line to a vacuum of 100 inches of water, sealing the entire system and watching the vacuum for at least one minute. A vacuum gauge attached in parallel to the apparatus measured the vacuum. If there is any observable loss of

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vacuum, the fittings were adjusted as needed until the vacuum did not change noticeably. The soil gas sample was then collected. No flow conditions occur when a sampling rate greater than 10 mL/min cannot be maintained without applying a vacuum greater than 100 inches of water to the sampling train.

The sampling train is left at a vacuum for no less than three minutes. If the vacuum does not subside appreciably after three minutes, the sample location is determined to be a no flow sample.

Forty soil vapor samples, including three duplicates, were collected from these soil vapor probes by a Jones Environmental, Inc. (ELAP 2882) chemist and analyzed in a mobile laboratory on July 27 and 28, 2021. Three duplicates, one per 10 soil vapor samples, were collected and analyzed by the chemist. One deep probe SV19 was unable to be set at 15-feet bgs due to oily conditions. Soil vapor analytical results are included as Appendix B.

Soil matrix samples were collected from Spud Field, 1905 East 21st Street, in Signal Hill, California in April 2005 and July 2021 and analyzed for TTLC metals including hexavalent chromium. The analytical data was used as Signal Hill specific background metal concentrations in two-way statistical analyses to prove the Null Hypothesis, i.e., the sample population of metals concentrations onsite is less than or equal to the sample population representative of background. These background metals analytical results are included as Appendix C.

All drilling, logging and sampling activities were conducted by or under the direct supervision of a State of California registered Professional Geologist, and in accordance with California Well Standards presented in the Department of Water Resources (DWR) Bulletins 74-81 and 74-90. The Site Geology and Hydrogeology section and boring logs were prepared by Mr. Scott R. Fagan, a State of California Professional Geologist PG #4289. Boring logs are included as Appendix D.

3.1 Site Geology - The site is located on the west flank of the Signal Hill uplift created by lateral movement on the Cherry Hill Fault (CHF) (part of the Newport Inglewood fault zone). The CHF is located north of the site and the site overlies the Gardena Syncline, an east-west trending down-fold of the local stratigraphy.

The surface sediments are Recent Alluvium consisting of sand, silt and clay which overlie the Lakewood Formation. Borings are logged as predominantly silt and clay with thin sections of sand.

The Gaspur Aquifer is the first groundwater below the site, below any boring depths achieved during drilling activities. No groundwater was detected in any soil boring.

3.2 Soil Matrix Analytical Results – Carbon chains C4-C12 were detected eight times in 57 soil matrix samples at a concentrations ranging from 0.052 mg/kg to 2,600 mg/kg; four detected concentrations: 1,100 mg/kg, 2,600 mg/kg, 510 mg/kg and 1,500 mg/kg exceed the screening threshold of 82 mg/kg. Carbon chains C13-C22 were detected 12 times in 57 soil matrix samples at concentrations ranging from 34 mg/kg to 2,500 mg/kg; five detected concentrations exceeded the screening threshold of 97 mg/kg. Carbon chains C23-C40 were detected 15 times in 57 soil matrix samples at concentrations ranging from 35 mg/kg to 2,200 mg/kg; none of these detected concentrations were greater than the screening threshold of 2,400 mg/kg (Table 1 and Figure 4).

The following metals were detected in concentrations greater than their respective reporting limits:
arsenic, barium, cobalt, trivalent chromium, copper, lead, nickel, selenium, vanadium and zinc (Table 1 and Figure 4). A detected concentration of arsenic, 20 mg/kg, exceeded the screening threshold.

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The volatile organic compounds (VOCs) benzene, n-butylbenzene, sec-butylbenzene, tert-butylbenzene, ethylbenzene, isopropylbenzene (cumene), methyl tert-butyl ether (MTBE), naphthalene, npropylbenzene, m,p-xylenes and o-xylene were detected in concentrations greater than their respective reporting limits (Table 3 and Figure 5). Detected concentrations of naphthalene exceed the screening limit.

Semi-volatile organic compounds (SVOCs) acenaphthene, anthracene, benzo(a)anthracene, 2,4- dinitrophenol, chrysene, 4,6-dinitro-2-methylphenol, 2,4-dinitrotoluene, 2,6-dinitrotoluene, fluorene, 2- methylnaphthalene, naphthalene, 4-nitroaniline, n-nitrosodi-n-propylamine, phenanthrene and pyrene were detected in the soil matrix at concentrations greater than their respective reporting limits. Detected concentrations of benzo(a)anthracene, 2,6-dinitrotoluene and naphthalene exceeded their respective screening levels (Table 4 and Figure 5).

3.3 Soil Vapor Analytical Results – The VOCs, benzene, n-butylbenzene, sec-butylbenzene, cis-1,2- dichloroethene, di-isopropylether, ethylbenzene, isopropylbenzene (cumene), 4-isopropyltoluene (cymene), methylene chloride, naphthalene, n-propylbenzene, tetrachloroethene, toluene, total xylenes and gasoline range organics (GRO) were detected in concentrations greater than their respective reporting limits in the vapor phase (Table 5 and Figure 6). All of these volatiles were detected at concentrations that exceeded their respective screening thresholds. The greatest detected concentration of benzene, 8,850 micrograms per cubic meter (µg/m3) was detected at SV7-15 adjacent to a previously abandoned oil well and along a pipeline corridor. Generally concentrations of volatiles in the vapor phase increased with depth.

3.4 Conclusions and Recommendations
Carbon chains, C4-C12, C13-C22, C23-C40, metals VOCs and SVOCs were detected in the soil matrix.

Sixteen volatile organic compounds were detected in the vapor phase in soil vapor underlying the site (Table 5 and Figure 6).

The carbon chains C4-C12 and C13-C22 were detected at concentrations greater than their respective screening thresholds (Table 1 and Figure 4). Arsenic was detected at concentrations greater than the screening threshold (Table 1 and Figure 4). Three VOCs/SVOCs in the soil matrix exceeded their respective screening thresholds. Seventeen volatile organic compounds in the vapor phase were detected at concentrations that exceeded their respective screening thresholds (Tables 3-5 and Figures 5 and 6).

As the proposed future development for the site is residential, a human health risk assessment is warranted based on the results of this Phase II ESA. The human health risk assessment should include an evaluation of potential health impacts to future residential, commercial and construction workers.

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4.0 CONCEPTUAL SITE MODEL
A conceptual site model was developed to identify the potential complete exposure pathways by which constituents detected in soil could impact human health (Figure 7).

The conceptual site model identifies potential sources, environmental release mechanisms, potential migration pathways, potential exposure pathways, potential exposure routes and potential human receptors onsite.

The conceptual site model identified the following potential complete exposure pathways:
• Future onsite resident

1. ingestion/dermal contact with surface soil

2. inhalation of constituents from surface soil entrained in dust

3. inhalation of VOCs from soil vapor in surface and subsurface soil that have migrated to indoor air
• Future commercial building occupant

1. ingestion/dermal contact with surface soil

2. inhalation of constituents from surface soil entrained in dust

3. inhalation of VOCs from soil vapor in surface and subsurface soil that have migrated to indoor air
• Future construction worker

1. ingestion/dermal contact with surface soil

2. inhalation of constituents from surface and subsurface soil entrained in dust

3. inhalation of VOCs from soil vapor in surface and subsurface soil that have migrated to outdoor air, including trenches
Consumption of fruit or vegetables grown in soil is not considered to be a complete potential exposure pathway under future site conditions.

Potential direct exposures (ingestion and dermal contact) to groundwater are not complete pathways as drinking water is provided by a remote municipal water supply, so there is little chance of incidental exposure. Discharge of groundwater to surface water also is not considered to be a complete migration pathway since there are no surface water bodies that are recharged by artesian flow or groundwater seepage in the vicinity of the site.

The potential for chemicals in soil to leach to underlying groundwater used as a drinking water source is considered very low as several aquitards or aquicludes exist below the maximum depth of impacted soils and groundwater used as a drinking water source.

There is very limited ecological habitat at and near the site. Wetlands were not observed onsite or at adjacent sites. There are no natural or undisturbed areas onsite. Based on the lack of viable ecological habitat at and near the site, there are no complete ecological pathways onsite.

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5.0 IDENTIFYING CHEMICALS OF CONCERN
All constituents detected at least one time in the soil matrix and in soil vapor underlying the site were quantitatively assessed using the appropriate exposure pathway in this risk assessment.

Pursuant to the following guidance documents, Selecting Inorganic Constituents as Chemicals of Concern for Risk Assessments at Hazardous Waste Sites and Permitted Facilities (DTSC 1997), Background Metals at Los Angeles Unified School Sites – Arsenic (DTSC 2005) and Arsenic Strategies, Determination of Arsenic Remediation, Development of Arsenic Cleanup Goals (DTSC 2009) the following statistical tests: (a) Wilcoxon-Mann-Whitney, (b) Gehan, (c) Tarone-Ware, (d) Multiple Box Plots, (e) Multiple Histograms and (f) Q-Q Plots, were used to determine whether detected concentrations of metals in the soil matrix onsite were within background concentrations. The results of these statistical analyses are included as Appendix E.

These two sample hypotheses tests with non-detects are based on the null hypothesis. The Null hypothesis tests whether the mean and median of the concentrations of each metal detected in onsite soils are less than or equal to the mean and median concentrations of the concentrations of the same metal detected in offsite or background soil samples.

The alternative hypothesis tested was whether the mean and median of the concentrations of detected metals in soils onsite are greater than the mean and median concentrations of the concentrations of the same metals in offsite or background soil samples.

The graphs (1) Multiple Box Plots, (2) Multiple Histograms and (3) Q-Q Plots with non-detects visually indicate whether the detected concentrations of metals in onsite soils are within the population of background metals.

The conclusion based on these quantitative statistical tests was all detected concentrations of metals onsite were within the background population. Selenium was not detected in the background samples, therefore this metal was quantitatively assessed in the human health risk assessment via the ingestion, dermal contact and inhalation routes of exposure.

Chemicals of concern quantitatively assessed in the risk assessment include: C4-C12, C13-C22, C23- C40, benzene, n-butylbenzene, sec-butylbenzene, tert-butylbenzene, ethylbenzene, isopropylbenzene, methyl tert-butyl ether, naphthalene, n-propylbenzene, m,p-xylenes, o-xylene, acenaphthene, anthracene, benzo(a)anthracene, 2,4-dinitrophenol, chrysene, 4,6-dinitro-2-methylphenol, 2,4-dinitrotoluene, 2,6- dinitrotoluene, fluorene, 2-methylnaphthalene, 4-nitoaniline, 4-nitrosodi-n-propylamine, pyrene, lead (via LeadSpread), and selenium in the soil matrix; benzene, di-isopropylether, ethylbenzene, isopropylbenzene, isopropyltoluene, methylene chloride, methyl tert-butyl ether, naphthalene, npropylbenzene, tetrachloroethylene (PCE), toluene, xylenes and gasoline range organics in the vapor phase via either or both the SFRWQCB ESL model or the Virginia DEQ VURAM model.

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6.0 TOXICITY ASSESSMENT
Toxicity values are combined with exposure factors to estimate noncancer adverse health effects and cancer risks. Toxicity values include reference doses (RfDs), reference concentrations (RfCs), unit risk factors (URFs) and slope factors (SFs) that are used to evaluate noncancer adverse health effects and cancer risks.

The State of California Office of Environmental Health Hazard Assessment (OEHHA) and the State of California Department of Toxic Substances Control (DTSC) Office of Human and Ecological Risk (HERO) have developed URFs SFs, RfCs and RfDs. Pursuant to regulatory agency guidance OEHHA's and HERO’s values are preferentially used instead of USEPA's when available, as OEHHA’s and HERO’s values are generally more conservative than USEPA’s (DTSC 2015, USEPA 2004).

If a constituent had both a risk factor and a reference concentration it was assessed as a carcinogen and as a noncarcinogen. The unit risk factors and reference concentrations were obtained from DTSC HERO (DTSC 2020), ATSDR, IRIS, OEHHA, PPRTV as listed in USEPA’s Regional Screening Levels (May 2021) and DTSC’s HERO Note 10 (February 2019).

The exposure point concentrations, the slope factors and reference doses for the constituents detected in the soil matrix and quantitatively assessed are presented in Table 6.

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7.0 EXPOSURE ASSESSMENT
The exposure assessment provides a scientifically defensible basis for the identification of potentially exposed human receptors and the most likely ways they might be exposed to chemicals of concern at the site. As defined by USEPA (1989), the following four components are necessary for chemical exposure to occur:
• A chemical source and a mechanism of chemical release to the environment • An environmental transport medium (e.g., soil) for the released chemical • A point of contact between the contaminated medium and the receptor (i.e., the exposure point)
• An exposure route (e.g., ingesting chemically-impacted soil) at the exposure point All four of these elements must be present for an exposure pathway to be considered complete and for chemical exposure to occur (USEPA 1989).

This HHRA evaluated the potential for receptors to be exposed to the maximum detected concentrations or the upper confidence level (UCL), whichever value was less, pursuant to the ProUCL User’s Guide (USEPA 2004) of the constituents detected in the top 15-ft of soil. The ProUCL model output is included as Appendix F.

The maximum concentrations of the VOCs detected in soil vapor at 5-ft or 20-ft underlying the site were used as the exposure point concentrations in the SFRWQCB ESL vapor intrusion model. Data collected from the soil matrix and soil vapor investigation in 2018 were used in the risk assessment. Exposure point concentrations are presented in Table 6.

7.1 Average and Reasonable Maximum Exposures - Typically two types of exposure scenarios are evaluated in a risk assessment; an average exposure scenario, and a reasonable maximum exposure (RME) scenario. The average exposure scenario represents a more typical exposure, believed to be most likely to occur, while the reasonable maximum exposure scenario represents a plausible worst case situation - one that is not very likely to occur. USEPA guidance (1989) recommends evaluating a reasonable maximum exposure scenario. The reasonable maximum exposure scenario estimates the exposure a receptor might receive using highly conservative intake assumptions (e.g., 90th or 95th percentile for most intake assumptions) and the upper confidence limit (UCL) on the mean of the chemical concentrations. It is assumed that by evaluating a reasonable maximum exposure scenario potential health risks to extremely sensitive individuals within a particular receptor population will be adequately addressed. As an added measure of conservatism, only a reasonable maximum exposure scenario was evaluated in this HHRA.

The DTSC PEA and USEPA guidance contain formulae that incorporate default values which were selected to be health protective. Some of these default values, such as, the exposure frequency, exposure time and exposure duration, were modified when evaluating the commercial worker and construction worker scenarios (DTSC 2015, USEPA 2004).

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8.0 RISK CHARACTERIZATION
The risk characterization process incorporates data from the exposure and toxicity assessments. The exposure assessment information necessary to estimate risks and hazards includes the estimated chemical intakes, exposure modeling assumptions, and the exposure pathways assumed to contribute to the majority of exposure for each receptor over a given time period (USEPA 1989a). The exposure parameters for assessing the constituents detected in the soil matrix are included as Table 7.

The method by which chemicals with carcinogenic and/or noncarcinogenic effects are evaluated to determine whether they pose a risk or an adverse impact to human health is discussed below, relative to the exposure pathways by which the receptors may be exposed to the exposure point concentrations of the chemicals of concern.

8.1 Ingestion and Dermal Contact Pathways - To provide an evaluation of chronic risk along the ingestion and dermal contact pathways the following equations for risk and hazard were used consistent with PEA guidance (DTSC 2015).

Risksoil = SFo x Cs x IRs, adult x EF x EDadult x 10-6 kg/mg BWadult x AT x EF
+ SFo x Cs x SAadult x AF x ABS x EF x EDadult x 10-6 kg/mg BWadult x AT x EF
+ SFo x Cs x IRs, child x EF x EDchild x 10-6 kg/mg
BWchild x AT x EF
+ SFo x Cs x SAchild x AF x ABS x EF x EDchild x 10-6 kg/mg BWchild x AT x EF
Hazardsoil = (1/RfDo) x Cs x IRs,child x EF x EDchild x 10-6 kg/mg BWchild x AT
+ (1/RfDo) x Cs x SAchild x AF x ABS x EFchild x EDchild x 10-6 kg/mg BWchild x AT
+ (1/RfDo) x Cs x IRs,adult x EF x EDadult x 10-6 kg/mg BWadult x AT
+ (1/RfDo) x Cs x SAadult x AF x ABS x EFadult x EDadult x 10-6 kg/mg BWadult x AT
Where:

SFo = cancer slope factor (mg/kg-day) -1
Cs = concentration in soil (mg/kg)
RfDo = oral reference dose (mg/kg-day)

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ABS = absorption fraction (dimensionless)
ED = exposure duration (years)
EF = exposure frequency (days/year)
BW = body weight (kg)
IRs = incidental soil ingestion rate (mg/day)
SA = skin surface area (cm2
/event)
AF = soil to skin adherence factor (mg/cm2
)
AT = averaging time (days)
Chemical specific values for the absorption fractions (ABS) parameter were obtained from USEPA and DTSC (USEPA June 2021; DTSC May 2020). Toxicity and exposure point concentrations are found in Table 6. Exposure parameters for assessing constituents detected in the soil matrix are presented in Table

7. The maximum concentration or the upper confidence level, whichever was less, of the constituents detected in the top 15-ft of soils were evaluated in this risk assessment for the residential, commercial worker and construction worker scenarios.

The exposure factors presented in Tables 6 and 7 provide a conservative estimate of chronic risk and hazard to human health due to exposure to the chemicals of concern detected in the soil matrix via the ingestion and dermal contact routes of exposure. The calculated estimates of risk and hazard due to exposure to constituents detected in the soil matrix are provided in Tables 8-11.

8.2 Inhalation Pathway Soil Matrix - To provide an evaluation of chronic risk along the inhalation pathway the following equations (DTSC 2015, USEPA 2009) for estimating risk and hazard due to exposure to constituents of concern detected in the soil matrix were used consistent with PEA guidance (DTSC 2015, USEPA 2009).

Semi-volatile organic compounds and metals in soil are evaluated in outdoor air using particulate emission factors (PEFs) to obtain concentrations of chemicals in dust. PEFs are used to develop an estimate of the concentration of a chemical in dust based on its concentration in soil. It assumes that the dust from the site is caused by the wind and not created by mechanical means (e.g. construction activities, tilling, automobile traffic, etc.) (DTSC 2015).

A default PEF of 1.36E+09 (m3
/kg) is used for the residential and commercial worker scenarios, and a PEF of 1.00E+06 is used for the construction worker scenario (DTSC 2015, USEPA 2009). It assumes an infinite source of chemicals, a vegetative cover of 50%, and a mean annual wind speed of 4.69 m/s. This is equivalent to a dust concentration of 0.76 g/m3 at the receptor. The default dispersion term (Q/C) of

90.80 (g/m2-s per kg/m3) is based on a site of 0.5 acres and dispersion modeling runs of 29 sites across the United States. The default Q/C provides a conservative estimate of the long-term exposure to dust (DTSC 2015).

Ca = (Cs/PEF) x 1000µg/mg
Where:

Ca = concentration in air, mg/m3
Cs = concentration in soil, mg/kg
PEF = particulate emission factor

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Riskair = IUR x Ca x ET x EF x ED
AT
Hazardair = (1/RfC x 1000µg/mg) x Ca x ET x EF x ED
AT
Where:

IUR = inhalation unit risk factor (µg/m3
)
-1
RfC = reference concentration (µg/m3
)
Ca = contaminant concentration in air (mg/m3
)
ET = exposure time (hours/day)
EF = exposure frequency (days/year)
ED = exposure duration (years)
AT = averaging time (hours)
The risk and hazard for the air pathway are based on either the exposure to volatile emissions for VOCs or the exposure to fugitive dust emissions for non-VOCs. The Office of Scientific Affairs defines a VOC as a chemical with a vapor pressure of 0.001 mm mercury or higher and a Henry’s Law Constant of 1 x 10-5 or higher. Exposure to a chemical via the air pathway can be adequately performed using either volatilization or fugitive dust scenarios; it is not necessary to do both (DTSC 2015).

For this risk assessment exposure to non-VOCs detected in the soil matrix via the inhalation pathway was performed using the fugitive dust scenario.

8.3 SFRWQCB ESL Vapor Intrusion Model - The SFRWQCB Environmental Screening Levels vapor intrusion model (2019, Rev. 2) was used to estimate potential risk and hazard due to exposure to volatiles in soil vapor in shallow soil (10-feet bgs or less) and in deeper soil (greater than 10-feet bgs).

Either the 95UCL or the maximum detected concentration was used as the exposure point concentration in this vapor intrusion model. Those chemicals of concern that had both reference doses and slope factors available were assessed as both noncarcinogenic and carcinogenic compounds.

The results of the vapor intrusion risk assessment due to exposure to carcinogenic VOCs in both shallow and deep soil is 3.03 x 10-3 for the residential scenario and 6.9 x 10-4 for the commercial worker scenario.

The results of the vapor intrusion risk assessment due to exposure to noncarcinogenic VOCs in both shallow and deep soil is 502 for the residential scenario and 117 for the commercial worker scenario. The model results are included on Tables 8 and 9 and in Appendices G and H.

The individual estimated risk value for benzene, ethylbenzene, methyl tert-butyl ether, naphthalene and tetrachloroethene exceeds the threshold of 1 x 10-6 for residential receptors. The individual estimated risk value for benzene, ethylbenzene, methyl tert-butyl ether and naphthalene exceeds the threshold of 1 x 10- 5 for commercial worker receptors. The individual estimated hazard value for benzene, methyl tert-butyl ether, naphthalene and gasoline range organics exceeds the threshold of 1 for residential occupants. The individual estimated hazard value for benzene, naphthalene and gasoline range organics exceeds the threshold of 1 for commercial workers.

8.4 VURAM - The Virginia Unified Risk Assessment Model (VURAM) was used to estimate the potential risks and hazards due to inhalation of VOCs by construction workers while working in a trench.

Either the 95UCL or maximum detected concentrations of the volatiles detected in soil vapor were used

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as the exposure point concentrations in VURAM.

The results of the vapor intrusion risk assessment due to exposure to carcinogenic volatiles in soil vapor for construction workers exposed in a trench estimated using the VURAM model was 9.18 x 10-7 and the hazard was 4 and are included in Table 10 and as Appendix I.

This estimated risk value does not exceed the threshold of 1 x 10-5 for construction workers working in a trench. The estimated hazard value of 4 does exceed the threshold and is attributable to gasoline range organics.

8.5 Noncancer Adverse Health Effects- Noncarcinogenic effects or hazards are typically evaluated by comparing an exposure level over a specified time period (e.g., a lifetime or 25 years), with a reference dose based on a similar time period. Hazard quotient values less than 1 indicate that potential exposures to noncarcinogenic COCs are not expected to result in toxicity (USEPA 1989). Summing the hazard quotient values to derive a hazard index (HI) provides an estimation of the total potential hazard due to a simultaneous exposure to all the noncarcinogenic COCs. However, summing hazard quotient values is not necessary when the chemicals of concern target different organs within the body (USEPA 1989, DTSC 2015). Although the noncarcinogenic chemicals of concern quantitatively assessed in this risk assessment target different organs within the body, the estimated hazard quotients were summed to derive a HI.

8.6 Lifetime Excess Cancer Risk - Slope factors are used to estimate the potential risk associated with exposure to individual COCs. The slope factor is multiplied by the chronic daily intake averaged over 70 years to estimate lifetime excess cancer risk. "Excess" or "incremental" cancer risk represents the probability of an individual developing cancer over a lifetime as a result of chemical exposure, over and above the baseline or "background" cancer risk in the general population. Cancer risks and noncancer health hazards estimated in the HHRA are regarded as estimated or theoretical results developed on the basis of the toxicity factors, chemical fate and transport, exposure assumption, and other inputs previously described. Cancer risks do not represent actual cancer cases in actual people. Rather, risks are calculated on the basis of an entirely hypothetical set of conditions. This assumed "exposure scenario" is developed to protect human health, and is based on standard USEPA and Cal-EPA methods and assumptions.

USEPA characterizes theoretical excess lifetime cancer risks below one in one million (10-6) as not of concern and has stated that risks between 10-6 and one in 10,000 (10-4) are "safe and protective of public health" (Federal Register 56(20):3535, 1991). Remedial action is not generally required by USEPA for sites with a theoretical lifetime excess risk of less than 10-4; whereas the State of California uses a riskmanagement approach (DTSC 2011). The DRAFT guidance indicates DTSC considers the risk range between 10-4 and 10-6 in risk management decisions (DTSC February 2020).

The more stringent target risk of 10-6 is typically applied to residential receptors. To provide perspective, a total theoretical lifetime excess cancer risk of one in 100,000 (10-5) is frequently accepted by Cal-EPA for worker receptors at California sites, and the target risk for chemicals evaluated under State Proposition 65 regulations is 10-5 (22CCR 12703).

8.7 Multipathway Cancer Risk - Based on regulatory guidelines, it is appropriate to combine risk estimates across exposure pathways for a given receptor. At the same time, exposure to multiple carcinogenic COCs is also typically considered to be additive. For exposures to multiple pathways and

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chemicals, the following equation was used to estimate total theoretical lifetime excess carcinogenic risks:
m n
Total Risk = Σ Σ CR i,p
p=1 i=1
Where:

Total Risk = Excess cancer risk from exposure to n chemicals via m pathways m = Number of exposure pathways
n = Number of chemicals
CR i,p = Potential cancer risk from exposure to chemical i via pathway p This equation was used to estimate the total potential cancer risks due to exposure to the carcinogenic COCs via the ingestion, dermal contact and inhalation routes of exposure. The estimated risks, total risk, estimated hazards and hazard index are presented in Tables 8-11.

8.8 Estimation of Risks and Hazards
Residential Scenario –
Estimated Risk Soil Ingestion and Dermal contact - The estimated risk due to exposure to constituents detected in the soil matrix via the ingestion and dermal contact exposure routes is 1.99 x 10-5 greater than the target threshold 1 x 10-6.

Estimated Risk Soil & Soil Vapor Inhalation - The estimated risk due to exposure to constituents detected in the soil matrix and soil vapor via the inhalation exposure route is 3.03 x 10-3 greater than the target threshold 1 x 10-6 and is attributable to benzene, ethylbenzene, methyl tert-butyl ether, naphthalene and tetrachloroethene in the vapor phase.

Hazard Quotients Soil Ingestion and Dermal Contact - The sum of the estimated hazard quotients due to exposure to constituents detected in the soil matrix via the ingestion and dermal contact exposure routes is 2.88, greater than 1, the target hazard value, and is attributable to C13-C22.

Hazard Quotients Soil & Soil Vapor Inhalation - The sum of the estimated hazard quotients due to exposure to constituents detected in the soil matrix via the inhalation exposure route is 3, greater than 1, the target hazard value. The sum of the estimated hazard quotients due to exposure to constituents detected in soil vapor is 503, greater than the target threshold value and is attributable to benzene, methyl tert-butyl ether, naphthalene and gasoline range organics.

Summed Risk - The total risk, summed across all exposure pathways for all carcinogenic chemicals of concern in the soil matrix and soil vapor, is 3.02 x 10-3, greater than the target risk.

Hazard Index – The total hazard, summed across all exposure pathways for all noncarcinogenic chemicals of concern in the soil matrix and soil vapor is 506, greater than the target hazard value. These estimated risk and hazards values are presented in Tables 8 and 11.

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Commercial Worker Scenario
Estimated Risk Soil Ingestion and Dermal contact - The estimated risk due to exposure to constituents detected in the soil matrix via the ingestion and dermal contact exposure routes is 7.23 x 10-6 less than the target threshold 1 x 10-5.

Estimated Risk Soil & Soil Vapor Inhalation - The estimated risk due to exposure to constituents detected in the soil matrix and soil vapor via the inhalation exposure route is 6.84 x 10-4 greater than the target threshold 1 x 10-5 and is attributable to benzene, ethylbenzene, methyl tert-butyl ether and naphthalene.

Hazard Quotients Soil Ingestion and Dermal Contact - The estimated hazard quotients due to exposure to constituents detected in the soil matrix via the ingestion and dermal contact exposure routes is 0.30, less than 1, the target hazard value.

Hazard Quotients Soil & Soil Vapor Inhalation - The estimated hazard quotients due to exposure to constituents detected in the soil matrix via the inhalation exposure route, 1.6E-05, is less than 1, the target hazard value. The sum of the estimated hazard quotients due to exposure to constituents detected in soil vapor is 117, greater than the target threshold value and is attributable to benzene, naphthalene and gasoline range organics.

Summed Risk - The total risk, summed across all exposure pathways for all carcinogenic chemicals of concern in the soil matrix and soil vapor, is 6.91 x 10-4, greater than the target threshold 1 x 10-5.

Hazard Index – The total hazard, summed across all exposure pathways for all noncarcinogenic chemicals of concern in the soil matrix and soil vapor is 117, greater than the target hazard value. These estimated risk and hazards values are presented in Tables 9 and 11.

Construction Worker Scenario – Soil Matrix
Estimated Risk Soil Ingestion and Dermal contact - The estimated risk due to exposure to constituents detected in the soil matrix via the ingestion and dermal contact exposure routes is 1.07 x 10-6 less than the target threshold 1 x 10-5.

Estimated Risk Soil & Soil Vapor Inhalation - The estimated risk due to exposure to constituents detected in the soil matrix and soil vapor via the inhalation exposure route is 9.38 x 10-7 less than the target threshold 1 x 10-5.

Hazard Quotients Ingestion and Dermal Contact - The estimated hazard quotients due to exposure to constituents detected in the soil matrix via the ingestion and dermal contact exposure routes is 1.55, greater than 1, the target hazard value.

Hazard Quotients Soil & Soil Vapor Inhalation - The estimated hazard quotients due to exposure to constituents detected in the soil matrix via the inhalation exposure route is 0.04, less than 1, the target hazard value. The sum of the estimated hazard quotients due to exposure to constituents detected in soil vapor is 4, greater than the target threshold value.

Summed Risk - The total risk, summed across all exposure pathways for all carcinogenic chemicals of concern in the soil matrix, is 2 x 10-6, less than the target threshold 1 x 10-5.

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Hazard Index – The total hazard, summed across all exposure pathways for all noncarcinogenic chemicals of concern in the soil matrix is 6, greater than the target hazard value. These estimated risk and hazards values are presented in Tables 10 and 11.

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9.0 MITIGATION MEASURES
Institutional controls, i.e., the required methane mitigation system to be installed subslab of the proposed buildings and paving of surface soils for parking effectively mitigates the risks and hazards to negligible conditions ensuring the site is safe for the future intended use as a residential/commercial property.

Methane mitigation subslab of proposed buildings is recommended based on the Methane Assessment (DL Science, Inc. July 15, 2021). The methane mitigation system should consist of a subslab impervious membrane placed inbetween geotextile or geocloth to protect it from sand above and the 4” thick gravel blanket below in conformance with the City of Signal Hill Oil and Gas Code §16.24.080 and City of Signal Hill Project Development Guide (June 2020). Perforated horizontal vent pipes should be placed in the 4” thick gravel blanket and tied into vertical vent risers (typically cast iron) placed inbetween the interior and exterior walls, less than 100-feet apart, extending a minimum of 3-feet above the roof line and should not terminate less than 100-feet from any opening (City of Signal Hill June 2020).

Although designed to capture and vent methane to the atmosphere, other volatile organic compounds in the subsurface (both in the soil matrix and soil vapor) also will be captured and vented by this system.

If an impervious surface paving area is 5,000 square feet or greater and contiguous to the proposed buildings, the paving should have vents spaced less than 100-ft apart consisting of four sided concrete boxes with traffic rated grates and 4” thick gravel blanket at the base. The vents should be designed to prevent surface water infiltration.

If a level of the parking structure that is below ground surface it should have an exhaust ventilation system that is in compliance with the California Mechanical Code.

All enclosed parking garages in North America are subject to ventilation standards established by the International Mechanical Code (IMC) and the American Society of Heating, Refrigeration, and Air- Conditioning Engineers (ASHRAE). The IMC and ASHRAE stipulate that garage ventilation systems run continuously during building-occupied hours, with an exception made for those that deploy carbon monoxide sensor-based, demand-controlled ventilation systems.

A soil management plan should be prepared to provide guidance to building contractors in the event discolored or odiferous soils or soils with elevated VOCs are discovered during onsite excavation and grading activities.

A Rule 1166 Permit/Compliance Plan should be obtained from the South Coast Air Quality Management District prior to site grading. VOC monitoring under an Air Quality Management District R1166 Permit ensures construction workers are protected from VOCs during earthwork.

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10.0 UNCERTAINTY ANALYSIS
The uncertainty analysis characterizes the propagated uncertainty in health risk assessments. These uncertainties are driven by variability in:
• The chemical data selection and assumptions used in the models with which concentrations at receptor locations were estimated.
• The variability of receptor intake parameters.
• The accuracy of toxicity values used to characterize exposure, hazards and cancer risks.

Additionally, uncertainties are introduced in the risk assessment when exposures to several substances across multiple pathways are summed.

Quantifying uncertainty is an essential element of the risk assessment process. According to USEPA's Guidance on Risk Characterization for Risk Managers and Risk Assessors, point estimates of risk "do not fully convey the range of information considered and used in developing the assessment" (USEPA 1992).

The following components of the risk assessment process can introduce uncertainties:
• Data Collection and Evaluation
• Exposure Assessment
• Toxicity Assessment
• Risk Characterization

10.1 Data Collection and Evaluation - The techniques used for data sampling and analysis and the methods used for identifying chemicals for evaluation in this risk assessment, may result in a number of uncertainties. These uncertainties are itemized below in the form of assumptions. • It was assumed that the nature and extent of chemical impacts on and near the site have been adequately characterized. If this assumption is not valid, then potential health impacts may be over- or underestimated.
• Systematic or random errors in the chemical analyses may yield erroneous data. These types of errors may result in a slight over- or underestimation of risk.

10.2 Exposure Assessment - A number of uncertainties are associated with the exposure assessment, including estimation of exposure point concentrations and assumptions used to estimate chemical intakes.

Key uncertainties associated with these components of the HHRA are summarized below.

10.2.1 Exposure Pathways - The exposure pathways evaluated in this HHRA are expected to represent the primary pathways of exposure, based on the results of the chemical analyses, and the expected fate and transport of these chemicals in the environment. Minor or secondary pathways may also exist, but often cannot be identified or evaluated using the available data. The contribution of secondary pathways to the overall risk from the site is not likely to be significant. In addition, intake assumptions are reflective of trends (usually for the most sensitive individual within an entire population), and as such are subject to intrinsic variability. In both cases, their presence introduces a level of uncertainty to this risk assessment process.

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10.3 Toxicity Assessment - Toxicity information for many chemicals is often limited. Consequently, there are varying degrees of uncertainty with the calculated toxicity values. Sources of uncertainty associated with toxicity values include:
• Using dose-response information from effects observed at high doses to predict the adverse health effects that may occur following exposure to the low levels expected from human contact with the agent in the environment.
• Using dose-response information from short-term exposures to predict the effects of long-term exposures.
• Using dose-response information from animal studies to predict effects in humans. • Using dose-response information from homogeneous animal populations or human populations to predict the effects likely to be observed in the general population consisting of individuals with a wide range of sensitivities.

To compensate for these uncertainties, USEPA typically applies a margin of safety when promulgating human toxicity values. Therefore, use of USEPA toxicity values likely results in an overestimation of potential hazard and risk.

10.4 Risk Characterization - The reasonable maximum exposure scenario risk characterization represents an over-estimation of risk. Site-specific information regarding depth below ground at which the constituents of concern were detected was not used in the equations. The reasonable maximum exposure scenario estimated the risk to the receptors based on the maximum detected concentrations or the UCLs for the constituents quantitatively assessed in this risk assessment.

10.5 Summary of Risk Assessment Uncertainties - The analysis of the uncertainties associated with this risk assessment indicates that the estimated risks and hazards derived from the equations in the PEA Manual (DTSC 2015), the RAGs Manual (USEPA 2009), the LeadSpread Model (DTSC) and the ESL and VURAM vapor intrusion models for the reasonable maximum exposure scenario represent an overestimation of risk. Although as outlined in the sections above, many factors can contribute to the over- or underestimation of risk, in general, a mixture of conservative and upper-bound input values were identified to estimate potential exposures. Compounding conservative and upper-bound input values in the risk assessment process are intended to lead to reasonable, maximum, health-conservative estimates.

The actual impacts to human health are most likely less than those estimated in this HHRA for the evaluated receptors and pathways.

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11.0 REFERENCES
California Environmental Protection Agency (Cal-EPA). 1992. Supplemental Guidance for Human Health Multimedia Risk Assessments of Hazardous Waste Sites and Permitted Facilities.

California Environmental Protection Agency (Cal-EPA) Department of Toxic Substances Control (DTSC). 1997. Selecting Inorganic Constituents as Chemicals of Potential Concern at Risk Assessments at Hazardous Waste Sites and Permitted Facilities. February 1997.

California Environmental Protection Agency (Cal-EPA) Department of Toxic Substances Control (DTSC). 2005. Final Report, Background Metals at Los Angeles Unified School Sites – Arsenic. June 6, 2005.

California Environmental Protection Agency (Cal-EPA) Department of Toxic Substances Control (DTSC). 2007. Arsenic Strategies, Determination of Arsenic Remediation, Development of Arsenic Cleanup Goals for Proposed and Existing School Sites. March 21, 2007.

California Environmental Protection Agency (Cal-EPA) Department of Toxic Substances Control (DTSC). 2011. Guidance for the Evaluation and Mitigation of Subsurface Vapor Intrusion to Indoor Air October 2011.

California Environmental Protection Agency (Cal-EPA) Department of Toxic Substances Control (DTSC). 2015. Preliminary Endangerment Assessment Guidance Manual.

Chernoff, G., W. Bosan and D. Oudiz. Determination of a Southern California Regional Background Arsenic Concentration in Soil.

DL Science, Inc. July 15, 2021. Summary Report for Methane Soil Gas Investigation at Town Center North West Site, Northeast Corner of Intersection of East Willow Ave. and Walnut Ave., Signal Hill, California (90755).

DTSC Human and Ecological Risk Office (HERO) Human Health Risk Assessment (HHRA) Note Number

3. June 2020.

DTSC HERO Human Health Risk Assessment Note Number 10. February 2019.

DTSC’s LeadSpread 8.0 Model.

Mearns Consulting, LLC. May 27, 2021. Phase I Environmental Site Assessment Northeast Corner of E Willow St. and Walnut Avenue, Town Center Northwest, Signal Hill, California 90755 (2 volumes).

Mearns Consulting, LLC. July 30, 2021. Phase II Environmental Site Assessment Northeast Corner of E Willow St. and Walnut Avenue, Town Center Northwest, Signal Hill, California 90755.

USEPA. May 2021. Regional Screening Levels.

United States Environmental Protection Agency (USEPA). July, 1996. Soil Screening Guidance: User's Guide. Office of Solid Waste and Emergency Response. Publication 9355.4-23.

HUMAN HEALTH RISK ASSESSMENT
Northeast Corner E. Willow St. and Walnut Avenue, Town Center Northwest site Signal Hill, California 90755
August 11, 2021 24 Mearns Consulting LLC
United States Environmental Protection Agency (USEPA). December, 2004. Risk Assessment Guidance for Superfund (RAGs), Office of Emergency and Remedial Response. EPA/540/1-9/002.

United States Environmental Protection Agency (USEPA). 2004. Risk Assessment Guidance for Superfund - Volume I - Human Health Evaluation Manual (Part B, Development of Risk-Based Preliminary Remediation Goals). Office of Emergency and Remedial Response. Publication 9285.7-01B.

United States Environmental Protection Agency (USEPA). 2009. Risk Assessment Guidance for Superfund - Volume I - Human Health Evaluation Manual (Part F, Supplemental Guidance for Inhalation Risk Assessment).

United States Environmental Protection Agency (USEPA). April, 2004. ProUCL Guidance.

United States Environmental Protection Agency (USEPA). ProUCL version 5.1.02 TABLES
Table 1 - Carbon Chains and Metals Analytical Results in Soil Matrix August 11, 2021 Mearns Consulting LLC
SAMPLE DATE As Ba Co Cr Cu Ni Pb Se V Zn C4-C12 C13-C22 C23-C40 ID SAMPLED mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg RSLr 0.68 15,000 23 120,000 3,100 400 390 390 23,000 82 97 230,000 DTSC-SLr 0.11 36,000 820 80 390 97 2,400
RSLi 3 220,000 350 1,800,000 47,000 800 5,800 5,800 350,000 420 560 3,500,000 DTSC-SLi 0.36 170,000 11,000 320 1,000 500 18,000
ESL Tier 1 0.067 390 23 120,000 180 86 32 2.4 18 340
SV1-5 7/12/2021 <5.5 68 5.4 9.8 8.8 6.4 <7.1 <6.9 15 27 <0.05 <5 <5 SV1-10 7/12/2021 <5.5 77 7.1 21 20 12 <7.1 <6.9 24 42 <0.05 <5 <5 SV1-15 7/12/2021 <5.5 45 <3.3 7 <5 3.6 <7.1 <6.9 6.6 22 <0.05 <5 <5 SV2-5 7/12/2021 <5.5 74 5.5 11 13 6.2 <7.1 <6.9 13 28 <0.042 <5 35 SV2-10 7/12/2021 <5.5 82 9.3 18 18 12 <7.1 <6.9 31 36 <0.045 <5 <5 SV2-15 7/12/2021 <5.5 81 6.6 21 14 11 <7.1 <6.9 28 36 <0.05 <5 <5 SV3-5 7/12/2021 <5.5 67 5.6 12 11 4.3 <7.1 <6.9 18 25 <0.042 <5 <5 SV3-10 7/12/2021 <5.5 50 6.4 18 17 9.5 <7.1 <6.9 31 34 <0.05 <5 <5 SV3-15 7/12/2021 <5.5 32 3.7 8.3 6.2 5 <7.1 <6.9 18 18 <0.05 <5 <5 SV4-5 7/12/2021 <5.5 63 8.2 13 14 8 <7.1 <6.9 25 26 <0.05 <5 <5 SV4-10 7/12/2021 <5.5 40 4.6 14 12 7 <7.1 <6.9 21 25 <0.05 <5 <5 SV4-15 7/12/2021 <5.5 26 3.7 8.1 6.8 5.7 <7.1 <6.9 14 20 <0.05 <5 <5 SV5-5 7/12/2021 <5.5 82 8.1 18 17 10 <7.1 <6.9 34 34 <0.05 <5 <5 SV5-10 7/12/2021 <5.5 47 5.1 12 11 7.8 <7.1 <6.9 21 24 <0.05 <5 <5 SV5-15 7/12/2021 <5.5 61 6.1 14 15 8.8 <7.1 <6.9 28 30 <0.05 <5 <5 SV6-5 7/13/2021 <5.5 83 7.6 14 14 8.5 <7.1 <6.9 24 28 <0.05 <5 <5 SV6-10 7/13/2021 <5.5 66 6.4 21 16 12 <7.1 <6.9 31 40 <0.05 <5 <5 SV6-15 7/13/2021 <5.5 42 4.3 9.4 9 6.4 <7.1 <6.9 14 27 <0.05 <5 <5 SV7-5 7/13/2021 <5.5 73 7.2 16 13 11 7.2 <6.9 27 34 <0.062 <5 <5 SV7-10 7/13/2021 <5.5 50 6.6 13 11 7.6 <7.1 <6.9 19 25 <0.071 <5 <5 SV7-15 7/13/2021 <5.5 37 3.6 10 8.4 6.7 <7.1 <6.9 16 20 <0.05 <5 <5 SV8-5 7/13/2021 <5.5 30 <3.3 5.7 7.8 4 19 <6.9 9.1 26 <0.042 <5 <5 SV8-10 7/13/2021 <5.5 58 10 12 11 7.8 <7.1 <6.9 21 25 <0.05 <5 <5 SV8-15 7/13/2021 <5.5 50 4.6 17 12 9.8 <7.1 <6.9 19 29 <0.05 <5 <5 SV9-5 7/13/2021 <5.5 3100 5.1 26 31 20 24 <6.9 28 73 <0.067 110 550 SV9-10 7/13/2021 <5.5 77 6.2 17 12 8.3 <7.1 <6.9 23 27 <0.043 <5 50 SV9-15 7/13/2021 <5.5 110 10 30 17 16 <7.1 <6.9 33 45 <0.05 <5 <5 SV10-5 7/13/2021 <5.5 650 10 25 31 24 42 <6.9 36 100 <0.084 510 650 SV10-10 7/13/2021 <5.5 49 4.9 10 8.3 6 <7.1 <6.9 16 20 <0.05 <5 52 SV10-15 7/13/2021 <5.5 81 11 21 15 13 <7.1 <6.9 36 42 <0.05 <5 <5 SV11-5 7/13/2021 <5.5 150 10 19 21 15 17 <6.9 29 60 <0.05 <5 160 SV11-10 7/13/2021 <5.5 130 8.5 15 10 8.1 <7.1 <6.9 23 28 <0.05 39 200 SV11-15 7/13/2021 <5.5 64 6 19 11 11 <7.1 <6.9 23 31 <0.05 <5 <5 SV12-5 7/13/2021 <5.5 83 5.4 12 7.8 6.4 <7.1 <6.9 18 23 <0.07 <5 <5 SV12-10 7/13/2021 <5.5 46 5.4 10 6.7 5.7 <7.1 <6.9 16 20 <0.05 <5 <5 SV12-15 7/13/2021 <5.5 32 3.3 7 <5 4.5 <7.1 <6.9 9.2 16 <0.05 <5 <5 SV13-5 7/13/2021 <5.5 83 7.1 15 9.8 8.7 <7.1 <6.9 23 31 <0.05 <5 <5 Table 1 - Carbon Chains and Metals Analytical Results in Soil Matrix August 11, 2021 Mearns Consulting LLC
SAMPLE DATE As Ba Co Cr Cu Ni Pb Se V Zn C4-C12 C13-C22 C23-C40 ID SAMPLED mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg RSLr 0.68 15,000 23 120,000 3,100 400 390 390 23,000 82 97 230,000 DTSC-SLr 0.11 36,000 820 80 390 97 2,400
RSLi 3 220,000 350 1,800,000 47,000 800 5,800 5,800 350,000 420 560 3,500,000 DTSC-SLi 0.36 170,000 11,000 320 1,000 500 18,000
ESL Tier 1 0.067 390 23 120,000 180 86 32 2.4 18 340
SV13-10 7/13/2021 <5.5 100 5.7 21 13 10 <7.1 <6.9 26 37 <0.05 <5 <5 SV13-15 7/13/2021 <5.5 46 4.5 12 8 7 <7.1 <6.9 16 26 <0.05 <5 <5 SV14-5 7/13/2021 <5.5 50 4.7 11 7.4 5.9 <7.1 <6.9 15 22 <0.05 <5 <5 SV14-10 7/13/2021 <5.5 88 5.6 22 12 9.1 26 <6.9 17 61 0.21 53 180 SV14-15 7/13/2021 <5.5 38 3.8 12 6.9 6.4 <7.1 <6.9 13 28 <0.05 <5 <5 SV15-5 7/13/2021 <5.5 110 4.9 12 9 6.7 <7.1 <6.9 19 28 <0.06 <5 <5 SV15-10 7/13/2021 <5.5 79 7.8 16 13 12 <7.1 <6.9 26 38 <0.056 <5 <5 SV15-15 7/13/2021 <5.5 64 4.9 11 6.9 7.7 <7.1 <6.9 16 26 <0.065 <5 <5 SV16-5 7/13/2021 <5.5 160 7.4 17 20 11 19 <6.9 24 63 <0.058 190 500 SV16-10 7/13/2021 <5.5 130 11 24 27 16 27 <6.9 36 86 <0.063 <5 <5 SV16-15 7/13/2021 <5.5 720 8 23 37 16 61 <6.9 28 90 0.26 150 200 SV17-5 7/13/2021 20 88 6.7 18 47 17 57 <6.9 21 180 0.052 34 650 SV17-10 7/13/2021 <5.5 170 9.2 20 21 13 12 <6.9 28 61 <0.05 <5 79 SV17-15 7/13/2021 <5.5 240 16 35 35 19 12 7.4 47 120 <0.05 <5 78 SV18-5 7/13/2021 <5.5 110 8.2 18 16 12 14 <6.9 28 66 <0.10 110 600 SV18-10 7/13/2021 <5.5 94 9.8 18 14 12 <7.1 <6.9 32 40 1100 1300 2200 SV18-15 7/13/2021 <5.5 100 7.7 25 16 16 <7.1 <6.9 35 54 0.48 <5 <5 SV19-5 7/13/2021 <5.5 74 6.9 14 11 11 <7.1 <6.9 24 33 2600 2400 <250 SV19-10 7/13/2021 <5.5 66 7.3 17 12 12 <7.1 <6.9 23 35 510 590 270 SV19-15 7/13/2021 <5.5 46 5.2 10 7.8 8.1 <7.1 <6.9 15 28 1500 2500 530 Notes:
mg/kg = milligram per kilogram
As = arsenic, Ba = barium, Co = cobalt, Cr = trivalent chromium, Cu = copper, Ni = nickel, Pb = lead, Se = selenium, V = vanadium, Zn = zinc <x = concentration is less than the Reporting Limit (x ), i.e., not detected (ND) SV1-5 = Soil Boring1, 5-feet below ground surface (bgs) BOLD = value exceeds the DTSC or USEPA screening level
Analytical results are included as Appendix A
Soil was collected from 5-feet, 10-feet bgs and 15-feet bgs from the same boring.

Only detected concentrations of metals are presented in this table. All other metals were ND.

ESL Tier 1 = San Francisco Bay Regional Water Quality Control Board Environmental Screening Levels 2019 (Rev. 2) RSLr = USEPA Regional Screening Level for residential soils, RSLi = USEPA Regional Screening Levels for industrial soils (May 2021) DTSC SLr = CalEPA DTSC Screening Level for residential soils, DTSC SLi = CalEPA DTSC Screening Level for industrial soils (June 2020) carcinogenic values were preferentially used for all screening levels, except nickel and TPH DTSC SL C17-C32, aromatic high and USEPA aromatic high values were used for C23-C40 DTSC SL C9-C16, aromatic medium and USEPA aromatic medium values were used for C13-C22 Table 2 - Background Metals Analytical Results in Soil Matrix August 11, 2021 Mearns Consulting LLC
SAMPLE DATE As Ba Co Cr Cu Ni Pb Se V Zn
ID SAMPLED mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg RSLr 0.68 15,000 23 120,000 3,100 400 390 390 23,000
DTSC-SLr 0.11 36,000 820 80 390
RSLi 3 220,000 350 1,800,000 47,000 800 5,800 5,800 350,000 DTSC-SLi 0.36 170,000 11,000 320 1,000
ESL Tier 1 0.067 390 23 120,000 180 86 32 2.4 18 340
Offsite-1 4/4/2005 5.2 97 8.1 21 25 12 12 <1.9 35 62
Offsite-5 4/4/2005 12 160 17 50 64 30 8.1 <1.9 75 99
Offsite-10 4/4/2005 12 170 14 32 35 22 5.6 <1.9 58 67
Offsite-20 4/4/2005 14 73 17 35 80 22 10 <1.9 67 95
SB1-5 7/6/2021 <5.5 84 11 36 40 21 8.8 <6.9 46 54
SB2-5 7/6/2021 <5.5 69 9.3 21 26 15 <7.1 <6.9 36 39
SB3-5 7/6/2021 <5.5 48 4.6 9 16 6.2 <7.1 <6.9 16 29
SB4-5 7/6/2021 <5.5 170 14 42 45 26 9.5 <6.9 58 74
SB5-5 7/6/2021 <5.5 97 16 30 40 27 8.5 <6.9 52 56
SB6-5 7/6/2021 <5.5 130 22 42 46 33 11 <6.9 71 85
SB7-5 7/6/2021 <5.5 80 12 24 26 19 <7.1 <6.9 43 47
SB8-5 7/6/2021 <5.5 180 17 38 37 32 11 <6.9 68 51
SB9-5 7/6/2021 <5.5 87 14 30 28 24 9 <6.9 54 38
SB10-5 7/6/2021 <5.5 98 13 27 30 23 7.5 <6.9 51 39
SB11-5 7/6/2021 <5.5 120 9.8 22 14 16 <7.1 <6.9 39 31
Notes:
mg/kg = milligram per kilogram
As = arsenic, Ba = barium, Co = cobalt, Cr = trivalent chromium, Cu = copper, Ni = nickel, Pb = lead, Se = selenium, V = vanadium, Zn = zinc <x = concentration is less than the Reporting Limit (x ), i.e., not detected (ND) SB1-5 = Soil Boring1, 5-feet below ground surface (bgs) Analytical results are included as Appendix B
ESL Tier 1 = San Francisco Bay Regional Water Quality Control Board Environmental Screening Levels 2019 (Rev. 2) RSLr = USEPA Regional Screening Level for residential soils, RSLi = USEPA Regional Screening Levels for industrial soils (May 2021) DTSC SLr = CalEPA DTSC Screening Level for residential soils, DTSC SLi = CalEPA DTSC Screening Level for industrial soils (June 2020) carcinogenic values were preferentially used for all screening levels, except nickel Table 3 - VOCs Analytical Results in Soil Matrix
August 11, 2021 Mearns Consulting LLC

SAMPLE DATE
Benzenen-Butylbenzenesec-Butylbenzenetert-ButylbenzeneEthylbenzeneIsopropylbenzeneMethyl tert-butyl etherNaphthalenen-Propylbenzenem,p-Xyleneo-Xylene ID SAMPLED mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg RSLr 1.2 3,900 7,800 7,800 5.8 1,900 47 2 3,800 550 650 DTSC-SLr 0.33 2,400 2,200 2,200 2
RSLi 5.1 58,000 120,000 120,000 25 9,900 210 8.6 24,000 2,400 2,800 DTSC-SLi 1.4 18,000 12,000 12,000 6.5
ESL Tier 1 0.025 0.43 0.028 0.042 2.1 2.1
SV1-5 7/12/2021 <0.0045 <0.0045 <0.0045 <0.0045 <0.0045 <0.0045 <0.0045 <0.0045 <0.0045 <0.0045 <0.0045 SV1-10 7/12/2021 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 SV1-15 7/12/2021 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 SV2-5 7/12/2021 <0.0042 <0.0042 <0.0042 <0.0042 <0.0042 <0.0042 <0.0042 <0.0042 <0.0042 <0.0042 <0.0042 SV2-10 7/12/2021 <0.0039 <0.0039 <0.0039 <0.0039 <0.0039 <0.0039 <0.0039 <0.0039 <0.0039 <0.0039 <0.0039 SV2-15 7/12/2021 <0.0044 <0.0044 <0.0044 <0.0044 <0.0044 <0.0044 <0.0044 <0.0044 <0.0044 <0.0044 <0.0044 SV3-5 7/12/2021 <0.0042 <0.0042 <0.0042 <0.0042 <0.0042 <0.0042 <0.0042 <0.0042 <0.0042 <0.0042 <0.0042 SV3-10 7/12/2021 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 SV3-15 7/12/2021 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 SV4-5 7/12/2021 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 SV4-10 7/12/2021 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 SV4-15 7/12/2021 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 SV5-5 7/12/2021 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 SV5-10 7/12/2021 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 SV5-15 7/12/2021 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 SV6-5 7/13/2021 <0.0058 <0.0058 <0.0058 <0.0058 <0.0058 <0.0058 <0.0058 <0.0058 <0.0058 <0.0058 <0.0058 SV6-10 7/13/2021 <0.0099 <0.0099 <0.0099 <0.0099 <0.0099 <0.0099 <0.0099 <0.0099 <0.0099 <0.0099 <0.0099 SV6-15 7/13/2021 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 SV7-5 7/13/2021 <0.006 <0.006 <0.006 <0.006 <0.006 <0.006 <0.006 <0.006 <0.006 <0.006 <0.006 SV7-10 7/13/2021 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 SV7-15 7/13/2021 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 SV8-5 7/13/2021 <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 SV8-10 7/13/2021 <0.0044 <0.0044 <0.0044 <0.0044 <0.0044 <0.0044 <0.0044 <0.0044 <0.0044 <0.0044 <0.0044 SV8-15 7/13/2021 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 SV9-5 7/13/2021 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 SV9-10 7/13/2021 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 SV9-15 7/13/2021 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 SV10-5 7/13/2021 <0.0056 <0.0056 <0.0056 <0.0056 <0.0056 <0.0056 <0.0056 <0.0056 <0.0056 <0.0056 <0.0056 SV10-10 7/13/2021 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 SV10-15 7/13/2021 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 SV11-5 7/13/2021 <0.0056 <0.0056 <0.0056 <0.0056 <0.0056 <0.0056 <0.0056 <0.0056 <0.0056 <0.0056 <0.0056 SV11-10 7/13/2021 <0.0058 <0.0058 <0.0058 <0.0058 <0.0058 <0.0058 <0.0058 <0.0058 <0.0058 <0.0058 <0.0058 SV11-15 7/13/2021 <0.0064 <0.0064 <0.0064 <0.0064 <0.0064 <0.0064 <0.0064 <0.0064 <0.0064 <0.0064 <0.0064 SV12-5 7/13/2021 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 SV12-10 7/13/2021 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 SV12-15 7/13/2021 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 SV13-5 7/13/2021 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 SV13-10 7/13/2021 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 SV13-15 7/13/2021 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 SV14-5 7/13/2021 <0.0056 <0.0056 <0.0056 <0.0056 <0.0056 <0.0056 <0.0056 <0.0056 <0.0056 <0.0056 <0.0056 SV14-10 7/13/2021 <0.0059 <0.0059 <0.0059 <0.0059 0.023 <0.0059 <0.0059 <0.0059 <0.0059 0.11 0.043 SV14-15 7/13/2021 <0.0057 <0.0057 <0.0057 <0.0057 <0.0057 <0.0057 <0.0057 <0.0057 <0.0057 <0.0057 <0.0057 SV15-5 7/13/2021 <0.0087 <0.0087 <0.0087 <0.0087 <0.0087 <0.0087 <0.0087 <0.0087 <0.0087 <0.0087 <0.0087 SV15-10 7/13/2021 <0.006 <0.006 <0.006 <0.006 <0.006 <0.006 <0.006 <0.006 <0.006 <0.006 <0.006 SV15-15 7/13/2021 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 SV16-5 7/13/2021 <0.0064 <0.0064 <0.0064 <0.0064 <0.0064 <0.0064 <0.0064 <0.0064 <0.0064 <0.0064 <0.0064 Table 3 - VOCs Analytical Results in Soil Matrix
August 11, 2021 Mearns Consulting LLC

Only detected concentrations of VOCs are presented in this table. All other VOCs were ND.

SAMPLE DATE
AcenaphtheneAnthraceneBenzo (a) anthracene2,4-DinitrophenolChrysene4,6-Dinitro-2-methylphenol2,4-Dinitrotoluene2,6-DinitrotolueneFluorene2-MethylnaphthaleneNaphthalene4-NitroanilineN-Nitrosodi-n-propylaminePhenanthrenePyrene ID SAMPLED mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg RSLr 3,600 18,000 1.1 130 110 5.1 1.7 0.36 2,400 240 2 27 0.078 1,800 DTSC-SLr 3,300 17,000 2,300 190 2
RSLi 45,000 230,000 21 1,600 2,100 7.4 1.5 30,000 3,000 8.6 110 0.33 23,000 DTSC-SLi 23,000 130,000 12.0 1,100 1,300 42 4.7 0.99 17,000 1,300 6.5 74 0.21 13,000 ESL Tier 1 12 1.9 0.63 3 0.023 6 0.88 0.042 7.8 45
SV1-5 7/12/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV1-10 7/12/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV1-15 7/12/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV2-5 7/12/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV2-10 7/12/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV2-15 7/12/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV3-5 7/12/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV3-10 7/12/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV3-15 7/12/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV4-5 7/12/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV4-10 7/12/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV4-15 7/12/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV5-5 7/12/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV5-10 7/12/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV5-15 7/12/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV6-5 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV6-10 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV6-15 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV7-5 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV7-10 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV7-15 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV8-5 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV8-10 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV8-15 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV9-5 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV9-10 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV9-15 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV10-5 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV10-10 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV10-15 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV11-5 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV11-10 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV11-15 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV12-5 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV12-10 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV12-15 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV13-5 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV13-10 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV13-15 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV14-5 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV14-10 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV14-15 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV15-5 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV15-10 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 SV15-15 7/13/2021 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 <0.33 Table 4 - SVOCs Analytical Results in Soil Matrix
August 11, 2021 Mearns Consulting LLC

Only detected concentrations of SVOCs are presented in this table. All other SVOCs were ND.

SAMPLE DATE
Benzenen-Butylbenzenesec-Butylbenzenecis-1,2-DichloroetheneDi-isopropyletherEthylbenzeneIsopropylbenzene4-IsopropyltolueneMethylene chlorideMethyl tert-butyl etherNaphthalenen-PropylbenzeneTetrachloroetheneToluenem,p-Xyleneso-XyleneGasoline Range Organics (GRO) ID SAMPLED µg/m3 µg/m3 µg/m3 µg/m3 µg/m3 µg/m3 µg/m3 µg/m3 µg/m3 µg/m3 µg/m3 µg/m3 µg/m3 µg/m3 µg/m3 µg/m3 µg/m3 RSLr 0.36 730 1.1 420 100 11 0.83 1,000 11 5,200 100 100 31 DTSC-SLr 0.097 210 420 8.3 1 0.46 83
RSLi 1.6 4.9 1,800 1,200 47 0.36 4,400 47 22,000 440 440 130 DTSC-SLi 0.42 880 1,800 35 3,100 12 2 350
ESL Tier 1 3.2 280 37 34 360 2.8 15 10,000 3,500 3,500 3,300 SV13-5 7/28/2021 <8 <12 <12 <8 <40 <8 <8 <8 <8 <40 <40 <8 16 <8 <16 <8 <2,000 SV13-5 REP 7/28/2021 <8 <12 <12 <8 <40 <8 <8 <8 <8 <40 <40 <8 25 <8 <16 <8 <2,000 SV13-15 7/28/2021 <8 <12 <12 <8 <40 <8 <8 <8 <8 <40 <40 <8 <8 <8 <16 <8 <2,000 SV14-5 7/28/2021 <8 <12 <12 <8 <40 <8 <8 <8 <8 <40 <40 <8 10 <8 <16 <8 <2,000 SV14-15 7/28/2021 <8 <12 <12 <8 <40 <8 <8 <8 <8 <40 <40 <8 <8 <8 <16 <8 <2,000 SV15-5 7/28/2021 <8 <12 <12 <8 <40 <8 <8 <8 <8 <40 <40 <8 37 <8 <16 <8 <2,000 SV15-15 7/28/2021 <8 <12 <12 <8 <40 <8 <8 <8 <8 <40 <40 <8 29 <8 <16 <8 <2,000 SV16-5 7/28/2021 <8 <12 <12 <8 <40 <8 <8 <8 <8 <40 <40 <8 15 <8 <16 <8 <2,000 SV16-15 7/28/2021 27 <12 <12 51 <40 74 <8 16 <8 <40 41 <8 18 44 287 84 46,800 SV17-5 7/28/2021 <8 <12 <12 <8 <40 <8 <8 <8 <8 <40 <40 <8 32 <8 <16 <8 <2,000 SV17-15 7/28/2021 <8 <12 <12 <8 <40 <8 <8 <8 <8 <40 <40 <8 10 <8 <16 <8 <2,000 SV18-5 7/28/2021 <8 <12 <12 <8 <40 <8 <8 <8 <8 <40 <40 <8 13 <8 <16 <8 <2,000 SV18-15 7/28/2021 1,150 <12 <12 <8 4,780 1,910 2,490 <8 <8 8,610 826 2,640 <8 <8 1,720 <8 3,380,000 SV19-5 7/28/2021 18 649 2,380 <8 <40 2,730 4,290 13 <8 121,000* 405 5,810 42 25 <16 <8 900,000 Notes: µg/m3
= micrograms per cubic meter
<x = concentration is less than the Reporting Limit, i.e., not detected; BOLD exceeds the screening level Blank cell screening threshold not available
Analytical results are included as Appendix C
Only detected concentrations of volatiles in the vapor phase are presented in this table Soil vapor was collected from dual-nested soil vapor probes installed at 5-feet bgs and 15-feet bgs ESL Tier 1 = San Francisco Bay Regional Water Quality Control Board Environmental Screening Levels 2019 (Rev. 2) RSLr = USEPA Regional Screening Level for residential air, RSLi = USEPA Regional Screening Levels for industrial air (May 2021) DTSC SLr = CalEPA DTSC Screening Level for residential air, DTSC SLi = CalEPA DTSC Screening Level for industrial air (June 2020) carcinogenic values were preferentially used for all screening levels * = dilution factor 1/3
Table 6 - Exposure Point Concentrations, Slope Factors and Reference Doses August 11, 2021 Mearns Consulting LLC
SOIL MATRIX ANALYTE MAX mg/kg 95UCL mg/kg SFo IUR RfDo RfCi C4-C12 2,600 199 4.0E-03b 3.0E+01b
C13-C22 2,500 346.3 4.0E-03b 3.0E+00b
C23-C40 2,200 246.7 4.0E-02b
benzene 0.0081 1.0E-01a 2.9E-05a 4.0E-03a 3.0E+00a
n-butylbenzene 1.7 5.0E-02a 2.0E+02a
sec-butylbenzene 0.068 1.0E-01a 4.0E+02a
tert-butylbenzene 0.012 1.0E-01a 4.0E+02a
ethylbenzene 0.023 1.1E-02a 2.5E-06a 1.0E-01a 1.0E+03a
isopropylbenzene 3 1.0E-01a 4.0E+02a
methyl tert-butyl ether 14 1.8E-03a 2.6E-07a 3.0E+03a
naphthalene 13 1.2E-01a 3.4E-05a 2.0E-02a 3.0E+00a
n-propylbenzene 5.7 1.0E-01b 1.0E+03b
m,p-xylenes 0.11 2.0E-01a 1.0E+02a
o-xylene 0.43 2.0E-01a 1.0E+02a
acenaphthene 1.6 6.0E-02a 2.4E+02a
anthracene 2.1 3.0E-01a 1.2E+03a
benzo(a)anthracene 1.3 1.0E-01a 1.1E-04a
2,4-dinitrophenol 0.92 2.0E-03a
chrysene 1.5 1.0E-03a 1.1E-05a
4,6-dinitro-2-methylphenol 0.4 8.0E-05a
2,4-dinitrotoluene 1.1 3.1E-01a 8.9E-05a 2.0E-03a
2,6-dinotrotoluene 1.2 1.5E+00a 3.0E-04a
fluorene 3 4.0E-02a 1.6E+02a
2-methylnaphthalene 12 4.0E-03a
naphthalene 5.2 1.2E-01a 3.4E-05a 2.0E-02a 3.0E+00a
4-nitroaniline 0.85 2.0E-02a 4.0E-03a 6.0E+00a
4-nitrosodi-n-propylamine 0.91 7.0E+00b 2.0E-03b
phenanthrene* 9.7
pyrene 8.5 3.0E-02a 1.2E+02a
selenium 7.4 5.0E-03a 2.0E+01a
lead 61 14.37 LeadSpread LeadSpread LeadSpread LeadSpread SOIL VAPOR ANALYTE MAX µg/m3 95UCL µg/m3
benzene 8,850 1,558 ESL & VURAM models ESL & VURAM models n-butylbenzene** 649 VURAM model
sec-butylbenzene** 2,380 VURAM model
cis-1,2-dichloroethene** 51 VURAM model
di-isopropylether** 4,780 VURAM model
ethylbenzene 2,730 292.3 ESL & VURAM models ESL & VURAM models isopropylbenzene** 4,290 427.5 VURAM model
p-isopropyltoluene** 321 32.1 VURAM model
methylene chloride 26 10.06 ESL & VURAM models ESL & VURAM models methyl tert-butyl ether 121,000 21,698 ESL & VURAM models ESL & VURAM models naphthalene 826 112.5 ESL & VURAM models ESL & VURAM models n-propylbenzene** 5,810 1,179 VURAM model
tetrachloroethene 42 17.88 ESL & VURAM models ESL & VURAM models toluene 4,210 814.4 ESL & VURAM models
m,p-xylenes 1,720 180.1 ESL & VURAM models
o-xylene 441 87.33 ESL & VURAM models
gasoline range organics 46,300,000 8,550,284 ESL & VURAM models Notes:
95UCL calculated using ProUCL version 5.1.02
EPCs are highlighted
SFo = Slope Factor, oral route of exposure (mg/kg-day)-1 IUR = inhalation unit risk factor, inhalation route of exposure (µg/m3) -1
RfDo = Reference Dose, oral route of exposure (mg/kg-day) RfCi = Reference Concentration, inhalation route of exposure (µg/m3) a DTSC HERO Note 10 (February 2019), bUSEPA RSL tables (May 2021) aromatic values were used for carbon chains (USEPA RSL May 2021) ** chemical specific data unavailable in ESL model, therefore analyte was not quantitatively assessed using the ESL model naphthalene was detected as a VOC and SVOC in the soil matrix, the greatest detected concentration was used as the EPC *phenanthrene was not quantitatively assessed as toxicity criteria is unavailable Table 7 - Exposure Parameters
August 11, 2021 Mearns Consulting LLC
Receptor Populations
Exposure Parameter Notation Commercial Construction Residential User Units Reference Worker Worker Adult Child
General Parameters
Body Weight BW 80 80 80 15 kg DTSC
Exposure Duration ED 25 1 20 6 years DTSC
Exposure Frequency EF 250 250 350 350 days/year DTSC
Exposure Time ET 8 8 24 24 hours/day DTSC
Soil Ingestion Pathway
Soil Ingestion Rate IR 100 330 100 200 mg/day DTSC
Averaging Time carcinogens 70dx365d/yr Atc 25550 25550 25550 25550 days DTSC Averaging Time noncarcinogens EDx365d/yr Atnc 9125 365 7300 2190 days DTSC Dermal Contact with Soil
Skin Surface Area SA 6,032 6,032 6,032 2,900 cm
2 /event OEHHA
Soil-to-Skin Adherence factor AF 0.2 0.8 0.07 0.2 mg/cm2 OEHHA Fraction of Chemical Dermally Absorbed ABS chem specific chem specific ch sp ch sp unitless DTSC Averaging Time carcinogens 70dx365d/yr Atc 25550 25550 25550 25550 days DTSC Averaging Time noncarcinogens EDx365d/yr Atnc 9125 365 7300 2190 days DTSC Inhalation of Outdoor Air
Particulate Emission Factor PEF 1.36E+09 1.00E+06 1.36E+09 1.36E+09 m 3 /kg DTSC
Exposure Time (site visit duration) ET 6 12 6 6 hours/day USEPA Averaging Time carcinogens 70dx365d/yrx24hr/d Atc 613200 613200 613200 613200 hours DTSC Averaging Time noncarcinogens EDx365d/yrx24h/d Atnc 219000 8760 175200 52560 hours DTSC Notes:

ABS = 0.1 for VOCs, 0.13 for naphthalene, 0.01 for most metals (DTSC June 2020; USEPA RSL May 2021) Table 8
Estimated Risks and Hazards - Residential
August 11, 2021 Mearns Consulting LLC
ANALYTE RISKo RISKi HAZARDo HAZARDi
soil
C4-C12 9.05E-01 4.67E-06
C13-C22 1.58E+00 8.15E-05
C23-C40 1.12E-01
benzene 1.54E-09 1.54E-14 3.69E-05 1.905E-09
n-butylbenzene 6.19E-04 5.993E-09
sec-butylbenzene 1.24E-05 1.20E-10
tert-butylbenzene 2.18E-06 2.11E-11
ethylbenzene 4.81E-10 3.76E-15 4.19E-06 1.62E-11
isopropylbenzene 5.46E-04 5.30E-09
methyl tert-butyl ether 4.79E-08 2.38E-13 3.29E-09
naphthalene 3.33E-06 2.89E-11 1.32E-02 3.06E-06
n-propylbenzene 1.04E-03 4.02E-09
m,p-xylenes 1.00E-05 7.76E-10
o-xylene 3.91E-05 3.03E-09
acenaphthene 5.20E-04 4.71E-09
anthracene 1.28E-04 1.23E-09
benzo(a)anthracene 2.77E-07 9.36E-12
2,4-dinitrophenol 8.37E-03
chrysene 3.20E-09 1.08E-12
4,6-dinitro-2-methylphenol 9.10E-02
2,4-dinitrotoluene 6.48E-07 6.48E-07 1.00E-02
2,6-dinotrotoluene 3.42E-06 7.28E-02
fluorene 1.52E-03 1.32E-08
2-methylnaphthalene 5.46E-02
4-nitroaniline 3.23E-08 1.19E-10 3.87E-03 9.99E-08
4-nitrosodi-n-propylamine 1.21E-05
pyrene 5.70E-03 4.99E-08
selenium 2.13E-02 2.61E-07
soil vapor
benzene 4.80E-04 1.50E+01
ethylbenzene 7.30E-05 7.90E-02
methylene chloride 3.00E-07 7.20E-04
methyl tert-butyl ether 3.40E-04 1.20E+00
naphthalene 2.10E-03 5.60E+01
tetrachloroethene 1.20E-06 1.30E-02
toluene 7.80E-02
xylenes 6.20E-01
gasoline range organics 4.30E+02
Sum 1.99E-05 3.00E-03 2.88 503
Total Risk = 3.02E-03
Total Hazard = 506
Table 9
Estimated Risks and Hazards - Commercial
August 11, 2021 Mearns Consulting LLC
ANALYTE RISKo RISKi HAZARDo HAZARDi
soil
C4-C12 9.40E-02 8.33E-07
C13-C22 1.64E-01 1.46E-05
C23-C40 1.17E-02
benzene 5.47E-10 1.06E-14 3.83E-06 3.40E-10
n-butylbenzene 6.42E-05 1.07E-09
sec-butylbenzene 1.28E-06 2.14E-11
tert-butylbenzene 2.27E-07 3.78E-12
ethylbenzene 1.71E-10 2.58E-15 4.34E-07 2.89E-12
isopropylbenzene 5.67E-05 9.46E-10
methyl tert-butyl ether 1.70E-08 1.64E-13 5.88E-10
naphthalene 1.34E-06 1.99E-11 1.56E-03 5.46E-07
n-propylbenzene 1.08E-04 7.17E-10
m,p-xylenes 1.04E-06 1.39E-10
o-xylene 4.06E-06 5.41E-10
acenaphthene 6.16E-05 8.42E-10
anthracene 1.52E-05 2.20E-10
benzo(a)anthracene 1.12E-07 6.43E-12
2,4-dinitrophenol 8.69E-04
chrysene 1.29E-09 7.42E-13
4,6-dinitro-2-methylphenol 9.44E-03
2,4-dinitrotoluene 2.30E-07 4.40E-12 1.04E-03
2,6-dinotrotoluene 1.22E-06 7.56E-03
fluorene 1.80E-04 2.37E-09
2-methylnaphthalene 5.67E-03
4-nitroaniline 1.15E-08 8.18E-11 4.01E-04 1.78E-08
4-nitrosodi-n-propylamine 4.30E-06
pyrene 6.75E-04 8.92E-09
selenium 1.42E-03 4.66E-08
soil vapor
benzene 1.10E-04 3.60E+00
ethylbenzene 1.70E-05 1.90E-02
methylene chloride 2.50E-08 1.70E-04
methyl tert-butyl ether 7.70E-05 2.80E-01
naphthalene 4.80E-04 1.30E+01
tetrachloroethene 2.70E-07 3.10E-03
toluene 1.90E-02
xylenes 1.50E-01
gasoline range organics 1.00E+02
Sum 7.23E-06 6.84E-04 0.30 117
Total Risk = 6.91E-04
Total Hazard = 117
Table 10
Estimated Risks and Hazards - Construction Worker
August 11, 2021 Mearns Consulting LLC
ANALYTE RISKo RISKi HAZARDo HAZARDi
soil
C4-C12 4.85E-01 2.27E-03
C13-C22 8.43E-01 3.95E-02
C23-C40 6.01E-02
benzene 8.02E-11 4.11E-12 1.97E-05 9.25E-07
n-butylbenzene 3.31E-04 2.91E-06
sec-butylbenzene 6.62E-06 5.82E-09
tert-butylbenzene 1.17E-06 1.03E-08
ethylbenzene 2.50E-11 3.06E-14 2.24E-06 7.88E-09
isopropylbenzene 2.92E-04 2.57E-06
methyl tert-butyl ether 2.49E-09 3.31E-16 1.60E-06
naphthalene 2.01E-07 5.66E-12 8.21E-03 1.48E-03
n-propylbenzene 5.55E-04 1.95E-06
m,p-xylenes 5.36E-06 3.77E-07
o-xylene 2.09E-05 1.47E-06
acenaphthene 3.23E-04 2.28E-06
anthracene 7.96E-05 5.99E-07
benzo(a)anthracene 1.68E-08 5.92E-11
2,4-dinitrophenol 4.48E-03
chrysene 1.94E-10 5.92E-13
4,6-dinitro-2-methylphenol 4.87E-02
2,4-dinitrotoluene 3.38E-08 3.88E-11 5.36E-03
2,6-dinotrotoluene 1.78E-07 3.90E-02
fluorene 9.47E-04 6.42E-06
2-methylnaphthalene 2.92E-02
4-nitroaniline 1.68E-09 1.96E-08 2.07E-03 4.85E-05
4-nitrosodi-n-propylamine 6.31E-07
pyrene 3.54E-03 2.43E-05
selenium 1.44E-02 1.27E-04
soil vapor
benzene 1.78E-07 2.08E-02
di-isopropylether 5.33E-03
ethylbenzene 7.63E-08 2.48E-04
isopropylbenzene 3.40E-02
isopropyltoluene 2.38E-03
methylene chloride 1.64E-12 1.15E-05
methyl tert-butyl ether 3.87E-07 4.30E-02
naphthalene 2.77E-07 1.99E-01
n-propylbenzene 4.17E-03
tetrachloroethene 3.83E-11 2.69E-04
toluene 1.51E-04
xylenes 4.41E-03
gasoline range organics 3.73E+00
Sum 1.07E-06 9.38E-07 1.55 4
Total Risk = 2.0E-06
Total Hazard = 6
Table 11
Summary of Risks and Hazards
August 11, 2021 Mearns Consulting LLC
Receptor Population
Residential Construction Commercial
∑ Risk 3.02E-03 2.00E-06 6.91E-04
Hazard Index 506 6 117
Notes:
∑Risk = Estimated risks due to ingestion and dermal contact and inhalation of constituents in soil and soil vapor Hazard Index = Estimated hazards due to ingestion and dermal contact and inhalation of constituents in soil and soil vapor

FIGURES

E WILLOW ST
E 27th ST
E 28th ST

ORANGE AVE

WALNUT AVE

CHERRY AVE

ROSE AVE

N GAVIOTA AVE

GUNDRY AVE
E 29th ST

E SPRING ST
405
Mearns Consulting LLC
Figure 1: Site Location Map
Town Center Northwest
Signal Hill, CA
N
0 500 feet
Base map: Google Earth 2020
SITE
SHP Drill Site
(not a part of
project site)

E WILLOW ST
E 27th ST

WALNUT AVE

N GAVIOTA AVE

ROSE AVE

GUNDRY AVE
E 28th ST
Mearns Consulting LLC
Figure 2: Site Map
Town Center Northwest
Signal Hill, CA
N
0 300 feet
Base map: Google Earth 2020
SITE
SHP Drill Site
(not a part of
project site)

E WILLOW ST
E 27th ST

WALNUT AVE

N GAVIOTA AVE

ROSE AVE
E 28th ST
Mearns Consulting LLC
Figure 3: Oil Wells:

Active, Idle, and Previously Abandoned
Town Center Northwest
Signal Hill, CA
Base map: Google Earth 2020
Oil well data source: CalGEM

EXPLANATION
Oil well location:

Active injection well
Active production well
Idle production well
Idle injection well
Previously abandoned well
N
0 200 feet
SITE
SHP Drill Site
(not a part of
project site)
03730457 (D-83)
03709241 (5)
03709829 (2)
03712157 (D19)
03709240 (3)
03712150 (D35)
03712155 (D34)
03721643 (DW-10)
03721642 (DW-9)
03721641 (DW-8) 03721640 (DW-7)
03727462 (D-82)
03722461 (D79)
03727384 (D-81)
03721639 (DW-6)
03730340 (D-82)
03721638 (DW-5)
03721663 (DW-12)
03721634 (DW-1)
03721636 (DW-3
03712159 (D24) 03712154 (4)
03712151 (2)
03712152 (D18)
03709398 (5)
03710207 (1)
03709373 (2) 03709196 (C41)
03712156 (D25)
03712158 (D26)
03709828 (1)
03712160 (D20)
037121533 (D21)
03722284 (D77)
03712142 (C33)
03721637 (DW-4)

E WILLOW ST
E 27th ST

WALNUT AVE

N GAVIOTA AVE

ROSE AVE
E 28th ST
Mearns Consulting LLC
Figure 4: Concentrations of Metals and
Carbon Chains That Exceed
Screening Thresholds
Town Center Northwest
Signal Hill, CA

EXPLANATION
Oil well location:

Active injection well
Active production well
Idle production well
Idle injection well
Previously abandoned well
N
0 200 feet
SITE
SHP Drill Site
(not a part of
project site)
14 pipelines
Pipeline
Above ground storage tank
Potential sump
Soil boring, sample depth indicated
in feet bgs, sample concentrations in
milligrams per kilogram,
As = arsenic
Base map: Google Earth, 2000
Oil well data source: CalGEM
03730457 (D-83)
03709241 (5)
03709829 (2)
03712157 (D19)
03709240 (3)
03712150 (D35)
03712155 (D34)
03721643 (DW-10)
03721642 (DW-9)
03721640 (DW-7) 03721641 (DW-8)
03727462 (D-82)
03722461 (D79)
03727384 (D-81)
03721639 (DW-6)
03730340 (D-82)
03721638 (DW-5)
03721663 (DW-12)
03721634 (DW-1)
03721636 (DW-3
03712159 (D24) 03712154 (4)
03712151 (2)
03712152 (D18)
03709398 (5)
03710207 (1)
03709373 (2)
03709196 (C41)
03712156 (D25)
03712158 (D26)
03709828 (1)
03712160 (D20)
037121533 (D21)
03722284 (D77)
03712142 (C33)
03721637 (DW-4)
510
SV10-5'
C13-C22
1100
1300
SV18-10'
C4-C12
C13-C22
20 SV17-5'
As
2600
2400
510
590
1500
2500
SV19-5'
C4-C12
C13-C22
SV19-10'
C4-C12
C13-C22
SV19-15'
C4-C12
C13-C22
SV7
SV6
SV3
SV1
SV10 SV5
SV15
SV16
SV17
SV18
SV19
SV9
SV4
SV2
SV8
SV11
SV12
SV13
SV14

E WILLOW ST
E 27th ST

WALNUT AVE

N GAVIOTA AVE

ROSE AVE
E 28th ST
Mearns Consulting LLC
Figure 5: Detected Concentrations of
VOCs and SVOCs in Soil
Town Center Northwest
Signal Hill, CA

EXPLANATION
Oil well location:

1. Units = milligrams per kilogram

2. <x = concentration is less than the Reporting Limit (x), i.e., not detected (ND)

3. BOLD = value exceeds the DTSC or USEPA screening level

4. Base map: Google Earth, 2000

5. Oil well data source: CalGEM
03730457 (D-83)
03709241 (5)
03709829 (2)
03712157 (D19)
03709240 (3)
03712150 (D35)
03712155 (D34)
03721643 (DW-10)
03721642 (DW-9)
03721640 (DW-7) 03721641 (DW-8)
03727462 (D-82)
03722461 (D79)
03727384 (D-81)
03721639 (DW-6)
03730340 (D-82)
03721638 (DW-5)
03721663 (DW-12)
03721634 (DW-1)
03721636 (DW-3
03712159 (D24) 03712154 (4)
03712151 (2)
03712152 (D18)
03709398 (5)
03710207 (1)
03709373 (2)
03709196 (C41)
03712156 (D25)
03712158 (D26)
03709828 (1)
03712160 (D20)
037121533 (D21)
03722284 (D77)
03712142 (C33)
03721637 (DW-4)
Ethylbenzene
m,p-Xylene
o-Xylene

0.023

0.11 0.043
n-Butylbenzene
sec-Butylbenzene
tert-Butylbenzene
Isopropylbenzene
Methyl tert-butyl ether
Naphthalene
n-Propylbenzene
m,p-Xylene
Acenaphthene
Anthracene
Benzo (a) anthracene
Chrysene
4,6-Dinitro-2-methylphenol
2,4-Dinitrotoluene
2,6-Dinitrotoluene
Fluorene
2-Methylnaphthalene
Naphthalene
4-Nitroaniline
N-Nitrosodi-n-propylamine
Phenanthrene
Pyrene
SV19-15'

1.7 <0.5
<0.5

1.7 12
13 4.1
<0.5

1.6 1.1

1.3 1.5
<0.33
<0.33
<0.33
3 <0.33
4 <0.33
<0.33

9.7 8.5
SV19-10'
<0.0069

0.068

0.012
1 14
<0.69

1.6 0.0075
<0.33
<0.33
<0.33
<0.33
<0.33
<0.33
<0.33
<0.33
<0.33
<0.33
<0.33
<0.33
<0.33
<0.33
1 <0.005
<0.005
3 1.2

7.7 5.7
<0.005
<0.33

2.1 <0.33
<0.33

0.4 1.1

1.2 1.1
12 5.2

0.85 0.91
2 0.87
SV14-10'
Benzene
n-Butylbenzene
sec-Butylbenzene
tert-Butylbenzene
Ethylbenzene
Isopropylbenzene
Naphthalene
n-Propylbenzene
Anthracene
2,4-Dinitrophenol
2-Methylnaphthalene
Naphthalene
Phenanthrene

0.0081

0.0052

0.035

0.005

0.023

0.031

0.036

0.035

0.82 0.92

2.2 0.44

0.77 SV18-10'
SV19-5'
SV7
SV6
SV3
SV1
SV10 SV5
SV15
SV16
SV17
SV18
SV19
SV9
SV4
SV2
SV8
SV11
SV12
SV13
SV14

E WILLOW ST
E 27th ST

WALNUT AVE

N GAVIOTA AVE

ROSE AVE
E 28th ST
Mearns Consulting LLC
Figure 6: Soil Vapor Analytical Results
Town Center Northwest
Signal Hill, CA

EXPLANATION
Oil well location:

1. Units = µg/m3 = micrograms per cubic meter

2. <x = concentration is less than the Reporting Limit (0.005), i.e., not detected (ND)

3. BOLD = value exceeds the screening level

5. * = dilution factor 1/3

4. Base map: Google Earth, 2000

5. Oil well data source: CalGEM
03730457 (D-83)
03709241 (5)
03709829 (2)
03712157 (D19)
03709240 (3)
03712150 (D35)
03712155 (D34)
03721643 (DW-10)
03721642 (DW-9)
03721641 (DW-8)
03721640 (DW-7)
03727462 (D-82)
03722461 (D79)
03727384 (D-81)
03721639 (DW-6) 03730340 (D-82)
03721638 (DW-5)
03721663
(DW-12)
03721634
(DW-1)
03721636 (DW-3
03712159 (D24) 03712154 (4)
03712151 (2)
03712152 (D18)
03709398 (5)
03710207 (1)
03709373 (2)
03709196 (C41)
03712156 (D25)
03712158 (D26)
03709828 (1)
03712160 (D20)
037121533 (D21)
03722284 (D77)
03712142 (C33)
03721637 (DW-4)
26 SV2-15' REP
Benzene
Isopropylbenzene
4-Isopropyltoluene
Methylene chloride
Toluene
Gasoline Range Organics
13 57
321
20 16
25,000
SV1-15'
Methylene chloride 17
SV2-15'
SV3-15'
8 17
Methylene chloride
Tetrachloroethene
SV3-5'
18 Benzene
Tetrachloroethene
Toluene
SV8-5'
20 23
15 SV4-15'
Tetrachloroethene 12
SV4-5'
22 SV6-15'
243
8 317,000
Benzene
Tetrachloroethene
Gasoline Range Organics
SV6-5'
17 SV10-15'
Tetrachloroethene 8
SV10-5'
9 SV15-15'
Tetrachloroethene 29
SV15-5'
37 SV16-15'
27 51
74 16
41 18
44 287
84 46,800
Benzene
cis-1,2-Dichloroethene
Ethylbenzene
4-Isopropyltoluene
Naphthalene
Tetrachloroethene
Toluene
m,p-Xylenes
o-Xylene
Gasoline Range Organics
SV16-5'
15 SV18-15'
1,150
4,780
1,910
2,490
8,610
826
2,640
1,720
3,380,000
Benzene
Di-isopropylether
Ethylbenzene
Isopropylbenzene
Methyl tert-butyl ether
Naphthalene
n-Propylbenzene
Tetrachloroethene
m,p-Xylenes
Gasoline Range Organics
SV18-5'
13 Benzene
n-Butylbenzene
sec-Butylbenzene
Ethylbenzene
Isopropylbenzene
4-Isopropyltoluene
Methyl tert-butyl ether
Naphthalene
n-Propylbenzene
Tetrachloroethene
Toluene
Gasoline Range Organics
SV19-5'
18 649
2,380
2,730
4,290
13 121,000*
405
5,810
42 25
900,000
SV17-15'
Tetrachloroethene 10
SV17-5'
32 SV12-15'
Tetrachloroethene 9
SV12-5'
8 SV13-5' REP
Tetrachloroethene 25
SV13-5'
16 Tetrachloroethene
SV11-15'
24 Tetrachloroethene
SV14-5'
10 SV9-15' REP
34 14
Tetrachloroethene
Toluene
SV9-15'
34 13
Benzene
Toluene
m,p-Xylenes
o-Xylene
Gasoline Range Organics
SV7-15'
8,850
4,210
799
441
43,300,000
Methylene chloride
SV5-15'
9 SV7
SV6
SV3
SV1
SV10
SV5
SV15
SV16
SV17
SV18
SV19
SV9
SV4
SV2
SV8
SV11
SV12
SV13
SV14
Mearns Consulting LLC
Figure 7: Conceptual Site Model
Town Center Northwest
Signal Hill, CA
Primary
Sources
Primary
Release
Mechanisms
Secondary
Sources
Transport
Mechanisms
Exposure
Media
Exposure
Routes
Potential Receptors Residential Occupational Construction and Excavation Ecological Receptors • Oil field
• Historic above
ground storage tanks
• Inoperable and
operating pipelines
• Previously
abandoned oil wells
• Historic sumps
Surface
soils
Subsurface
soils
Outdoor air
Indoor air
Outdoor air
Indoor air
Inhalation
Inhalation
Inhalation
Inhalation

 

 
Inhalation
particulates   
Volatilization and
migration in soil
gas
Soil
Ingestion   
Contact Dermal contact   
Volatilization and
migration in soil
gas
Disposal
practices
leaking

APPENDIX A
Sierra Analytical Labs, Inc.

July 12 and 13, 2021
Soil Matrix Data
Mearns Consulting LLC
RE:Town Center Northwest
Santa Monica, CA 90405
738 Ashland Avenue
Susan Mearns
Attached are the results of the analyses for samples received by the laboratory on 07/12/21 15:44.

The samples were received by Sierra Analytical Labs, Inc. with a chain of custody record attached or completed at the submittal of the samples.

The analyses were performed according to the prescribed method as outlined by EPA, Standard Methods, and A.S.T.M.

The remaining portions of the samples will be disposed of within 30 days from the date of this report.

If you require any additional retaining time, please advise us.

Sincerely,
19 July 2021
Richard K. Forsyth
Laboratory Director
Work Order No.: 2107160
Sierra Analytical Labs, Inc. is certified by the California Department of Health Services (DOHS), Environmental Laboratory Accredidation Program (ELAP) No. 2320.

Project:

Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/19/21 09:26
Town Center Northwest
Sample ID Laboratory ID Matrix Date Sampled

ANALYTICAL REPORT FOR SAMPLES
Date Received
SV1-5 2107160-01 Soil 07/12/21 08:54 07/12/21 15:44
SV1-10 2107160-02 Soil 07/12/21 10:39 07/12/21 15:44
SV1-15 2107160-03 Soil 07/12/21 10:43 07/12/21 15:44
SV2-5 2107160-04 Soil 07/12/21 11:20 07/12/21 15:44
SV2-10 2107160-05 Soil 07/12/21 11:23 07/12/21 15:44
SV2-15 2107160-06 Soil 07/12/21 11:36 07/12/21 15:44
SV3-5 2107160-07 Soil 07/12/21 12:35 07/12/21 15:44
SV3-10 2107160-08 Soil 07/12/21 12:39 07/12/21 15:44
SV3-15 2107160-09 Soil 07/12/21 12:44 07/12/21 15:44
SV4-5 2107160-10 Soil 07/12/21 13:09 07/12/21 15:44
SV4-10 2107160-11 Soil 07/12/21 13:18 07/12/21 15:44
SV4-15 2107160-12 Soil 07/12/21 13:21 07/12/21 15:44
SV5-5 2107160-13 Soil 07/12/21 13:50 07/12/21 15:44
SV5-10 2107160-14 Soil 07/12/21 14:02 07/12/21 15:44
SV5-15 2107160-15 Soil 07/12/21 14:07 07/12/21 15:44

Page 1 of 80 ends

Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/19/21 09:26
Town Center Northwest
Metals by EPA 6000/7000 Series Methods
Sierra Analytical Labs, Inc.

Analyte Result Limit
Reporting
Units Dilution Batch Prepared Analyzed Method Notes
SV1-5 (2107160-01) Soil Sampled: 07/12/21 08:54 Received: 07/12/21 15:44 Silver ND 2.0 mg/kg 1 B1G1308 07/13/21 07/14/21 17:06 EPA 6010B Arsenic ND 5.5 " " " " " "
Barium 68 6.0 " " " " " "
Beryllium ND 2.2 " " " " " "
Cadmium ND 2.5 " " " " " "
Cobalt 5.4 3.3 " " " " " "
Chromium 9.8 2.3 " " " " " "
Hexavalent Chromium ND 0.10 " " B1G1307 07/13/21 07/14/21 17:48 EPA 7199A Copper 8.8 5.0 " " B1G1308 07/13/21 07/14/21 17:06 EPA 6010B Mercury ND 0.90 " " B1G1309 07/13/21 07/13/21 20:26 EPA 7471A Molybdenum ND 5.2 " " B1G1308 07/13/21 07/14/21 17:06 EPA 6010B Nickel 6.4 3.0 " " " " " "
Lead ND 7.1 " " " " " "
Antimony ND 8.0 " " " " " "
Selenium ND 6.9 " " " " " "
Thallium ND 17 " " " " " "
Vanadium 15 5.1 " " " " " "
Zinc 27 7.0 " " " " " "
SV1-10 (2107160-02) Soil Sampled: 07/12/21 10:39 Received: 07/12/21 15:44 Silver ND 2.0 mg/kg 1 B1G1308 07/13/21 07/14/21 17:06 EPA 6010B Arsenic ND 5.5 " " " " " "
Barium 77 6.0 " " " " " "
Beryllium ND 2.2 " " " " " "
Cadmium ND 2.5 " " " " " "
Cobalt 7.1 3.3 " " " " " "
Chromium 21 2.3 " " " " " "
Hexavalent Chromium ND 0.10 " " B1G1307 07/13/21 07/14/21 17:48 EPA 7199A Copper 20 5.0 " " B1G1308 07/13/21 07/14/21 17:06 EPA 6010B Mercury ND 0.81 " " B1G1309 07/13/21 07/13/21 20:26 EPA 7471A Molybdenum ND 5.2 " " B1G1308 07/13/21 07/14/21 17:06 EPA 6010B Nickel 12 3.0 " " " " " "
Lead ND 7.1 " " " " " "
Antimony ND 8.0 " " " " " "
Selenium ND 6.9 " " " " " "
Thallium ND 17 " " " " " "
Vanadium 24 5.1 " " " " " "
Zinc 42 7.0 " " " " " "

Page 2 of 80 ends

Project Number:

Project Manager:

Reported:

Mearns Consulting LLC
738 Ashland Avenue [none]
Santa Monica CA, 90405 Susan Mearns 07/19/21 09:26
Town Center Northwest
Metals by EPA 6000/7000 Series Methods
Sierra Analytical Labs, Inc.

Analyte Result Limit
Reporting
Units Dilution Batch Prepared Analyzed Method Notes
SV1-15 (2107160-03) Soil Sampled: 07/12/21 10:43 Received: 07/12/21 15:44 Silver ND 2.0 mg/kg 1 B1G1308 07/13/21 07/14/21 17:06 EPA 6010B Arsenic ND 5.5 " " " " " "
Barium 45 6.0 " " " " " "
Beryllium ND 2.2 " " " " " "
Cadmium ND 2.5 " " " " " "
Cobalt ND 3.3 " " " " " "
Chromium 7.0 2.3 " " " " " "
Hexavalent Chromium ND 0.10 " " B1G1307 07/13/21 07/14/21 17:48 EPA 7199A Copper ND 5.0 " " B1G1308 07/13/21 07/14/21 17:06 EPA 6010B Mercury ND 0.90 " " B1G1309 07/13/21 07/13/21 20:26 EPA 7471A Molybdenum ND 5.2 " " B1G1308 07/13/21 07/14/21 17:06 EPA 6010B Nickel 3.6 3.0 " " " " " "
Lead ND 7.1 " " " " " "
Antimony ND 8.0 " " " " " "
Selenium ND 6.9 " " " " " "
Thallium ND 17 " " " " " "
Vanadium 6.6 5.1 " " " " " "
Zinc 22 7.0 " " " " " "
SV2-5 (2107160-04) Soil Sampled: 07/12/21 11:20 Received: 07/12/21 15:44 Silver ND 2.0 mg/kg 1 B1G1308 07/13/21 07/14/21 17:06 EPA 6010B Arsenic ND 5.5 " " " " " "
Barium 74 6.0 " " " " " "
Beryllium ND 2.2 " " " " " "
Cadmium ND 2.5 " " " " " "
Cobalt 5.5 3.3 " " " " " "
Chromium 11 2.3 " " " " " "
Hexavalent Chromium ND 0.10 " " B1G1307 07/13/21 07/14/21 17:48 EPA 7199A Copper 13 5.0 " " B1G1308 07/13/21 07/14/21 17:06 EPA 6010B Mercury ND 0.90 " " B1G1309 07/13/21 07/13/21 20:26 EPA 7471A Molybdenum ND 5.2 " " B1G1308 07/13/21 07/14/21 17:06 EPA 6010B Nickel 6.2 3.0 " " " " " "
Lead ND 7.1 " " " " " "
Antimony ND 8.0 " " " " " "
Selenium ND 6.9 " " " " " "
Thallium ND 17 " " " " " "
Vanadium 13 5.1 " " " " " "
Zinc 28 7.0 " " " " " "

Page 3 of 80 ends

Signal Hill City CouncilJuly 12, 2022

Signal Hill City Council
July 12, 2022