The soil samples were labeled, documented on a Chain-of-Custody (COC) form, and placed in an insulated cooler for transport to K Prime Inc. (K Prime) in Santa Rosa, California. All samples were transported under proper COC protocol where they were relinquished to K Prime. The sampling frequency and analysis was determined based on the requirements of the California Department of Substances Control Interim Guidance for Sampling Agricultural Properties (Third Edition). The eight samples collected in the grass area were composited by K Prime Inc. into four discrete samples and analyzed for Organochlorine Pesticides and Arsenic.
The composite sample (COMP-3-0-6”), near the former residence, was analyzed for Organochlorine Pesticides, Arsenic and Lead. The sample (S9) adjacent to the former Boiler Room was analyzed for hydrocarbons in the diesel and heavy oil range.
Analytical Results
The lab analyzed the two-point composite samples for Organochlorine Pesticides by United States Environmental Protection Agency (EPA) Method 3546/8081, Arsenic and/or Lead by EPA Method 3050B/6020B. EPA Method 8015B was used to analyze Hydrocarbons in the diesel and heavy oil range. The certified analytical laboratory report is included as an attachment to the end of this letter.
RGH
CONSULTANTS
Soil Sampling Summary Former Yountville Elementary School Phase II ESA March 29, 2024 Project Number: 6860.018.PW.2
The results of the Phase II sample event compare the soil analytical results to the publica�on of background concentra�ons of metals found in Quaternary Alluvium/Old Alluvium type soils in the project area. This work was done a�er the Napa County Complex fires to reveal the background metal concentra�ons naturally occurring within soil for different geologic units. This was used to assess if levels of metals at the school site are background or were the result of metals being used for pest control at the project site. The laboratory results detected arsenic concentra�ons ranging from 4.15 to 5.35 mg/kg, which is less than the reported background concentra�on of 8.88 mg/kg. The sample results detected lead at
16.1 mg/kg, which is less than the reported background concentra�on of 117 mg/kg.
Organochlorine Pes�cides and diesel range organics were not detected above the laboratory repor�ng limits.
Conclusions
Arsenic and Lead were detected below background concentra�on levels for alluvial soils. Organochlorine pes�cides and diesel range organics were not detected above the laboratory repor�ng limits. Therefore, the project site doesn't appear to have been affected by pes�cides, arsenic, lead or fuel oil.
RGH
CONSULTANTS
Soil Sampling Summary Former Yountville Elementary School Phase II ESA March 29, 2024 Project Number: 6860.018.PW.2
We trust this provides the informa�on you require at this �me. If you have ques�ons please contact the project manager.
Very truly yours,
RGH Consultants
Jeana M. Lopez
Project Geologist
Ryan E. Padget cc: Pound Management, Inc.
Senior Engineer Atn: Patrick McCreary and
Sean Grinnell
[email protected]
[email protected]
EGC:REP:jml:brw
Electronically submited
htps://rghgeo.sharepoint.com/sites/shared/shared documents/project files/6751-7000/6860/6860.018.pw.2 former yountville es phase 2 sampling/.01 - psa/6860.018.pw.2 phase 2 sampling summary leter.docx Atachments:
K-Prime Cer�fied Analy�cal Laboratory Report
References:
Geocon Consultants, February 2024. Phase I ESA Report. Former Yountville Elementary School, 6554 Yount Street, Yountville, Napa County, California. Geocon Project No. S2738-07-01.
Table 1. Cleanup Goals for Metals in Soil, Napa County/Atlas Fire Incident KL Geologic Area. htps://www.countyofnapa.org/DocumentCenter/View/6816/2017-Napa-Fire-Complex-NapaBackgroundTable-V1-PDF Report 4675-257125-257137-01
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