ARCHIVED REPORTS_REMEDIAL INVESTIGATION REPORT 2000

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R,Pan secaod Phase Subsurfue Investigation City of Stockton. Barom Island, Stodaon, CA May 20. 1992 VMW2.1D t lead using a citric extraction test. The results of the STLC analyses detected soluble lead concentrations ranging from 0.81 to 1.6 ppm. None of these concentrations exceed the 5 ppm STLC maximum limit for lead. No volatile organics were detected in any of the samples analyzed by EPA method 8240. The laboratory results for the soil samples are presented in Table 4. Laboratory reports, chain of custody documentation, and laboratory QA/QC data, are included in Appendix F. 6.2 Groundwater Laboratory analysis recorded priority pollutant metals above method detection limits in the groundwater samples collected from wells MW-1 through MW-9. Although none of the lev--Is detected exceeded the Total Threshold Limit Concentration values as listed in Title 22 of the California Code of Regulations, some of the samples contained concentrations of arsenic (BI- MW4 and 8), cadmium (BI-MW1), chromium (BI-MWI and 2), and selenium (BI-MW1, 4 and 8) above their State Primary Maximum Contaminant Level (MCL). The only volatile organic detected was acetone (120 para per billion, ppb) in well BI-MW-4. The laboratory results for the water samples are presented in Table 5. Laboratory reports, chain of' custody documentation, and laboratory QA/QC data, are included in Appendix G. 6.2.1 Wells Located on Adiacent Siter Three groundwater monitoring wells located at the former WPRR property (WPRR-MW I through MW3) were sampled on March 18, 1992 (Appendix D). This site is located directly northwest of the Banner Island property and subsurface investigations are being conducted concurrently at both sites. Laboratory analysis indicated a majority of the Title 22 metals are above method detection limits in the groundwater samples collected from the three wells. As with the Banner Island samples, Roaossi"Y 10 �I