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Pesticide Screening Report Reeves Sand&Gravel December 18,2019 Page 2 of 3 oxidizes readily to form inert compounds in short periods of time(days to weeks).The primary constituents of concern from historic agricultural chemical application for the Site are OCPs, lead,and arsenic. SAMPLING PROCEDURES On December 9, 2019, Condor collected one soil sample evenly dispersed across each approximately 5 acres of the Site(48.6 acres),for a total of 9 samples. Soil samples were collected at the surface [0-0.5 feet below ground surface(bgs)]. Samples were collected by directly inserting sample containers into the upper six inches of soil. Soil samples were placed in a chilled cooler and transported under chain-of-custody procedures to BC Laboratories,Inc.of Bakersfield,California(ELAP#1186)in Bakersfield,California for analysis. LABORATORY ANALYSES AND RESULTS All nine samples were analyzed for OCPs by EPA Method 8081 A,lead,and arsenic by EPA Method 6010B. The laboratory report and chain of custody sheet are included in the Attachment. Arsenic and lead were detected at low concentrations in all samples, ranging from 3.1 to 6.3 milligrams per kilogram (mg/kg) arsenic and from 4.0 to 6.3 mg/kg lead.No OCPs were detected at or above the laboratory reporting limits in any of the samples.Laboratory analytical results are summarized in Table 1,below. Table 1—Laboratory Analytical Results—Arsenic and Lead Constituent Units: mg/kg Sample ID Date Sampled EPA Method 6010B Arsenic Lead Detection Limits m 1.0 2.5 Residential Screening Levels NA, Back round= 1.0-12 80 S-1 12/9/19 3.6 4.0 S-2 12/9/19 3.8 4.5 S-3 12/9/19 4.8 5.6 S-4 12/9/19 6.3 6.3 S-5 12/9/19 3.8 4.6 S-6 12/9/19 3.1 4.3 S-7 12/9/19 3.5 4.5 S-8 1 12/9/19 5.1 6.0 IL S9 12/9/19 4.3 5.8 Units: mg/kg:milligrams per kilogram,parts per million(ppm).NA=Not applicable.DTSC recommends comparison to background Residential Screening Levels:DTSC HERO Note 3 Screening levels for lead are documented in the Department of Toxic Substances Control(DTSC), Human Ecological Risk Division (HERO), Human Health Risk Assessment (HHRA) Note 3, DTSC-modified Screening Levels (DTSC-SLs), April 2019. The residential screening level for lead is 80 mg/kg, and all results are well below this screening level and are representative of background lead concentrations for the Stockton region.Background lead concentrations for the Stockton region typically range between 2 and 30 mg/kg. For arsenic, DTSC recommends comparison to background arsenic concentrations. Background arsenic concentrations for the Stockton region typically range between 1 and 12 mg/kg. All arsenic concentrations are within typical background arsenic concentrations for the Stockton region. ;R� CONDOR