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Site Investigation Work Plan-Second Revision Raymond Investment Corporation Former Helena Chemical Facility Page 6 these reporting limits. Two alternatives were developed. The first alternative to be considered was to prioritize one or two classes of analytes, and/or matrices, and then select the best laboratory. However, prioritizing one or two groups of contaminants of concern runs counter to the intended purpose of this investigation.The results of this investigation should lead to elimination and prioritization of some groups of possible contaminants of concern. The second alternative to be considered was to send the samples to different laboratories. It was observed that all of the laboratories easily met the reporting requirements for nitrogen containing analytes. The second alternative is marginally feasible for soil samples because the samples are collected in tubes and need to be sealed, chilled, and minimally disturbed according to Environmental Protection Agency standards. In addition, manual separation of soil would introduce the potential for cross-contamination, bias, and error. Simply collecting more samples would expand the sampling interval and decrease the comparability of the data. Condor conferred by phone and email with the CVRWQCB. Condor has proposed in this revision of the work plan that soil samples will be sent to BC Laboratories for analysis. Condor proposes that groundwater samples will be sent to BSK Laboratories for pesticide analysis including fumigant pesticide analysis, and CalTest Laboratories for LUFT 5 metals, and nitrogen compound analysis. The screening levels for soil and groundwater are summarized in Constituents of Concern, Screening Levels,and Proposed Laboratory Reporting Limits, Appendix C.The selected laboratory reporting limits are included in the Helena Chemical-Sampling and Analysis Plan Summary Table,Appendix C. The CVRWQCB has indicated that if constituents of concern are detected at concentrations below primary/secondary MCLS, but above other screening levels (such as PHGs, notification levels, background levels), data should be further evaluated to determine the degree of impact on groundwater beneficial uses and whether further action is required. If it is determined that further action(remediation) is required, cleanup to levels other than background levels should be justified through a Technical and Economic Feasibility Analysis (TEFA). With the exception of where background levels exceed the MCLS, cleanup levels cannot be set higher than the MCLS. Cleanup levels can be addressed further in a feasibility study. Furthermore, if constituents of concern in soil are detected above DTSC-SLs or RSLs, data should be further evaluated based on site specific conditions to determine if there is a risk to human health and/or threat to groundwater (i.e. leaching concerns), and whether further action is required. Threats to groundwater should be addressed through DI-WET testing and/or modeling. The CVRWQCB letter dated September 10, 2015 indicated that, "Analytical methods developed by the California Department of Health(DHS)that are capable of quantification of 1,2,3-TCP at the notification level/detection limit for purposes of reporting (DLR) of 0.005 ug/L are acceptable. The selected laboratory may perform analysis for 1,2,3-TCP using one of the DHS gas chromatography/mass spectrometry (GC/MS) methods - Purge and Trap GC/MS or Liquid-Liquid Extraction GC/MS." BSK laboratories will perform the analysis for fumigant pesticides, including 1,2,3-TCP using the DHS methods as described above. 3.1 DATA QUALITY INDICATORS AND MEASUREMENT QUALITY OBJECTIVES BC Laboratories reports that the data will have a relative percent difference of 30 percent. This metric will be evaluated by confirming that the laboratories matrix spikes, surrogates, and duplicates fall within those limits. One rinsate sample will be collected on each day of sampling. If the laboratory analytical results for the rinsate samples indicate that some analytes have been detected, then samples collected that day will be re-evaluated and detected concentrations within 30 percent of the rinsate detected w +.� CONDOR