REMOVAL ACTION CERTIFICATION
CUPERTINO UNION SCHOOL DISTRICT
SEDGWICK ELEMENTARY SCHOOL EXPANSION PROJECT
CUPERTINO, CALIFORNIA
1. Certification of Remedial or Removal Action:
I hereby certify that the following information is true and correct to the best of my knowledge.
April 30, 2019
Project Manager Date
2. Tai Eate 5/3/2819
Unit Chief Date
So Baker 5/3/2019
3. Branch Chief Date
Certification Statement: Based upon the information which is currently and actually known to the Department,
× The Department has determined that all appropriate response actions have been completed, that all acceptable engineering practices were implemented and that no further removal/remedial action is necessary.
The Department has determined, based upon a remedial investigation or site characterization that the site poses no significant threat to public health, welfare or the environment and therefore implementation of removal/remedial measures is not necessary.
_The Department has determined that all appropriate removal/remedial actions have been completed and that all acceptable engineering practices were implemented; however, the site requires ongoing operation and maintenance (O&M) and monitoring efforts. The site will be deleted from the "active" site list following (1) a trial operation and maintenance period and (2) execution of a formal written settlement between Department and the responsible parties, if appropriate. However, the site will be placed on the Department's list of sites undergoing O&M to ensure proper monitoring of long-term cleanup efforts.
Site Name and Location: (Street address, County, City and zip code) Sedgwick Elementary School Expansion Project
10480 Finch Avenue
Cupertino, California 95014
Santa Clara County
Cupertino Union SD, Sedgwick Elementary School Expansion Project (Project Code 204271-11) A. List any other names that have been used to identify this site:
- None
B. Address of site if different from above:
C. Assessor's Parcel Number: - 375-40-067 (1.48 acres)
Responsible Parties: (Use extra pages if necessary.)
Name: Mr. Travis J. Kirk
Title: Senior Director, Facilities Operations
Firm: Cupertino Union School District
Address: 10301 Vista Drive
City: Cupertino, California
Zip: 95014
Telephone: (408) 252- 3000 Extension 61-370
Relationship To Site: (such as generator, hauler, etc.) Senior Director, Facilities Operations
Current Landowner/Operator: Cupertino Union School District Brief Description and History of the Site: (Include previous and current uses of site, a brief description of the cleanup action and concentrations of significant hazardous substances left on site)
The Cupertino Union School District (District) has expanded the existing Sedgwick Elementary School through the purchase of an adjoining 1.48-acre property identified by the Santa Clara County Assessor's Office as Assessor Parcel Number 375-40-067, located at 10480 Finch Avenue, Cupertino, California (Site). The District currently has no plans to develop the expansion property. The expansion property will not increase the number of students or classrooms at the existing Sedgwick Elementary School. Potable water and sewer services will continue to be provided by the local municipality.
Historically, the Site operated as an orchard from 1939 to 1956 and has been used as residential property since 1956 to 2018. Two small, single-room dwellings were located to the south of a workshop. The dwellings were of wood- Cupertino Union SD, Sedgwick Elementary School Expansion Project (Project Code 204271-11) frame construction, resting on concrete blocks. A 500-gallon gasoline underground storage tank (UST) was removed from the Site in 1996. The Santa Clara Valley Water District subsequently issued a March 26, 1997 case closure letter stating that no further action related to the UST release was required.
The Site is bounded to the north by Phil Lane followed by single family residential subdivisions; to the east by Sedgwick Elementary School, followed by South Tantau Avenue and single family residential subdivisions; to the south by the Sedgwick Elementary School playfield, followed by single family residential subdivisions; and, to the west by single family residential subdivisions.
A Preliminary Environmental Assessment (PEA) and Supplemental Site Investigation (SS) were completed to investigate and delineate, respectively, the Site for the following environmental conditions that may pose a threat to human health or the environment:
• Organochlorine pesticides (OCPs) and arsenic in soils from historic agricultural use;
• Lead in soils from the weathering of lead-based paint potentially used on existing and historic on-site building structures;
• OCPs in soils from potential termiticide use around existing and historic on- site building structures with wood components;
• Polychlorinated biphenyls (CBs) in soils from the weathering of sealant compounds used in existing and historic building structures; and • Volatile organic compounds and total petroleum hydrocarbons as gasoline in soils from former on-Site UST.
The results of the PEA screening level risk assessment estimated the total risk from chemicals of concern (COCs) identified in soils at the Site to be 3.2 x 10-5, which had a potential increased cancer risk of greater than 1 in 1,000,000 (=10-6). The total health hazard index from COCs identified in soils at the Site was estimated to be 0.46, which does not provide an increased health hazard index (i.e., >1).
Therefore, a response action to reduce or eliminate chlordane- and lead-impacted soils in the area of the workshop/single-room dwelling and residence was recommended.
The purpose of the response action was to mitigate potential risk to human health and the environment by the excavation and off-site disposal of soils containing concentrations of chlordane and lead exceeding the DTSC-modified screening level for chlordane and lead of 0.43 milligrams per kilogram (mg/kg) and 80 mg/kg, respectively. A screening-level human health risk assessment was conducted using the residential (also known as unrestricted) land-use scenario.
The RAW activities focused on excavating approximately 300 cubic yards (cy) or approximately 15 truckloads of chlordane- and lead-contaminated soils. DTSC approved the RAW for implementation on April 26, 2018. Removal action field activities began on October 2, 2018 and were completed on October 30, 2018.
The excavated soil was temporarily stockpiled on-site and characterized for waste Cupertino Union SD, Sedgwick Elementary School Expansion Project (Project Code 204271-11) disposal. Approximately 257 tons (approximately 160 cy), 12 truckloads, of soils classified as non-hazardous waste were transported to Republic Services, Inc.
Newby Isiand Landfill Facility located in Militas, Santa Clara County, California for disposal. The actual volume of soils removed from the Site was less than the estimated volume (300 cy) due to the discovery of deep concrete foundation walls, at several locations, that reduced the area of interior excavation and volume of soils requiring removal.
Confirmation soil sampling and chemical analyses were conducted when the planned soil excavation activities were completed. Confirmation soil samples were collected from the bottom and side walls of the excavation areas and were chemically analyzed by an analytical laboratory for the presence of OPs and lead. The results of the confirmation soil sampling and subsequent screening level risk assessment indicate that the objectives and cleanup goals of the response action have been met.
Post response action activities human health risk screening evaluation concluded that the total risk from COCs identified in soil confirmation samples collected at the Site was estimated to be 5.02 x 10-7 , which does not present an increased cancer risk of greater than 1 in 1,000,000 (>106). The total health hazard index from COCs identified in soils at the Site was estimated to be 0.01, which does not present an increased health hazard index (i.e., >1). Therefore, further remediation at the Site for OCPs in soils is not warranted.
Lead concentrations reported in confirmation soil samples collected at the Site ranged from 8.2 to 55 mg/kg. Using the calculated 95 percent upper confidence limit for lead of 24 mg/kg, a risk assessment was performed using the DTSC lead risk assessment spreadsheet model (LeadSpread Version 8). Based on the LeadSpread output, exposure to the lead concentrations detected at the Site will result in a 90th percentile blood lead concentration of 0.6 micrograms per deciliter in children which is below the Office of Environmental Health Hazard Assessment's blood toxicity level of 1 micrograms per liter. Therefore, further remediation for lead in soils at the Site is not warranted.
The Removal Action Completion Report (RACR) concludes that removal action standards and objectives have been achieved, and that post-removal action Site conditions do not pose a significant threat to human health or the environment.
Therefore, the RACR recommended the issuance of a "Site Certification" from DTSC regarding completion of the removal action for the Sedgwick Elementary School Expansion Project.
DTSC staff conducted a Site visit on October 2, 2018 to verify proper implementation of the RAW. Based on DTSC staff observations, the removal activities were consistent with those presented in the approved RAW.
Confirmation soil sample results verified that removal action objectives and cleanup goals were achieved and that the Site no longer poses an unacceptable risk to human health or the environment. On February 28, 2019, DTSC approved Cupertino Union SD, Sedgwick Elementary School Expansion Project (Project Code 204271-11) the revised RACR and certified that all response actions have been completed and further removal/remedial actions are not necessary for the Site.
Iype of Site: (Check appropriate response)
Included in Bond Expenditure Plan? Yes No X
RCRA-Permitted Facility_ Bond - funded
RCRA Facility Closure RP - funded
*NPL No Federal Facility No
Other (i.e., walk-in): Schools _Explain Briefly:
7. Size of Site: (Based on Expenditure Plan definition of size) Small Medium Large Extra Large
8. Dates of Remedial or Removal Action:
A. Initiated: October 2, 2018 B. Completed: October 30, 2018 *Per SARA, any NPL site that is not permanently cleaned must be scheduled for a follow-up visit after 5 years to verify that cleanup measures are still satisfactory.
9. Response Action Taken on Site: (check appropriate action) X! _Removal Action (satisfactory abatement of site)
Final Remedial Action
RCRA Enforcement/Closure action
No action, further investigation verified that no cleanup action at site was needed.
A. Type of Remedial or Removal Action (e.g. Excavation and disposal, cap, on- site treatment?): Excavation and Off-site disposal.
B. Estimated quantity of waste associated with the site (i.e., tons/gallons/cubic yards) which was:
treated Amount:
untreated (capped sites) Amount:
3. X removed Amount: 160 cubic yards
10. Cleanup Levels/Standards:
A. What were the cleanup standards established by the Department of Toxic Substances Control (DTSC) pursuant to the final remedial action plan (RAP) or workplan (if cleanup occurred as the result of a removal action (RA) prior to development of a RAP)?
Cupertino Union SD, Sedgwick Elementary School Expansion Project (Project Code 204271-11) Chlordane 0.43 mg/kg
Lead 80.0 mg/kg
B. Were the specified cleanup standards met? Yes X No_
C. If "no", why not:
11. DTSC Involvement in the Remedial or Removal Action:
A. Did the Department order the Remedial or Removal Action? Yes No X Date of Order
B. Did the Department review and approve the following plans/procedures? (indicate date of review/approval if done):
X Sampling Analysis Procedures Date: April 26, 2018
X Health & Safety Protections Date: April 26, 2018
X _Removal/Disposal Procedures Date: April 26, 2018
_Removal Action Workplan Date: April 26, 2018
C. If site was abated by a responsible party, did the Department receive a signed statement from a licensed professional on all phases of the Remedial Actions? (indicate date of statement)
Removal Action Workplan Date January 25, 2018
Removal Action Completion Report Date February 26, 2019 D. Did a registered engineer or geologist verify that acceptable engineering practices were implemented?
Yes. X No Name Alan Churchill, P.G., No. 9378
E. Did the Department confirm completion of all Remedial Actions? Yes X No Date of verification February 28, 2019
(i.e. manifest, sampling, demonstrated installation and operation of treatment) F. Did the Department (directly or through a contractor) actually perform the Remedial Action?
Yes No X Name of Contractor:
G. Was there a community relations plan in place? Yes_X_No.
H. Was a removal action workplan developed for this site? Yes_X_No.
Cupertino Union SD, Sedgwick Elementary School Expansion Project (Project Code 204271-11) I. Did DTSC hold a public meeting regarding the draft RAW? Yes. _No X J. Were public comments addressed? No comments were received.
Yes No _X Date of DTSC analysis and response:
K. Are all the facts cited above adequately documented in the DTSC files? Yes X_ No_
If no, identify areas where documentation is lacking.
12. EPA Involvement in the Remedial or Removal Action:
A. Was the EPA involved in the site cleanup? Yes No X
B. If yes, did EPA concur with all remedial actions? Yes No _N/A B. EPA comments N/A
EPA staff involved in cleanup (Name, Title):
13. Other Regulatory Agency Involvement in the Cleanup Action: N/A Agency: Activity:
RWQCB
ARB
CHP
Caltrans
Other
Name of contact persons and agency:
14. Post-Closure Activities: N/A
A. Will there be post-closure activities at this site? (e.g. Operation and Maintenance) B. Yes No X If yes, describe:
B. Have post-closure plans been prepared and approved by the Department? Yes No N/A
C. What is the estimated duration of post-closure (including operations and maintenance) activities? years.
D. Are deed restrictions proposed or in place? Yes No X If "yes", have deed restrictions been recorded with the County recorder? Yes No Date:
Cupertino Union SD, Sedgwick Elementary School Expansion Project (Project Code 204271-11) If "no", who is responsible for assuring that the deed restrictions are recorded? Who is the Department contact? No deed restrictions were required.
Name/Phone Number
E. Has cost recovery been initiated? Yes X No _
If yes, amount received $41,585.44 has been paid on the project with an outstanding balance of $0.00 as of April 30, 2019.
F. Were local planning agencies notified of the cleanup action? Yes No X If yes, the name and address of agency:
15. Expenditure of Funds and Source:
(Information to be supplied by Toxic Accounting Unit)
Funding Source and amount expended:
HWCA $ HSA $
HSCF $ RCRA $
-
RP Other$
Federal Cooperative Agreement $
Other (Site Remediation Account) $
16. Additional Comments:
None.
Cupertino Union SD, Sedgwick Elementary School Expansion Project (Project Code 204271-11)