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Rcview Comments for Revised Site Investigation Work Plan—June 2015 Former Helena Chemical Facility Page 3 In summary no one laboratory has the "lowest commercially available and achievable reporting limits" Selection of a laboratory based on broadiv such stated criteria is not possible based on Condor's review of 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 intendedupu ose 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 reouirements 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. However, soil samples collected through a 12-inch interval could be cut or split into two 6-inch intervals. Condor consulted with the CVRWOCB to develop the proposed Sampling and Analysis Plan (SAP). Condor has proposed in this revision of the work plan that soil samples will not be split and the samples will be sent to BC Laboratories. Condor proposes that groundwater samples will be sent to BSK Laboratories for fumigant pesticide, organo-phosphate, and organo-chlorine pesticide analysis,and CalTest Laboratories for LUFT 5 metals,and nitro en compound analysis. 3. Similarly, the proposed RL for each chemical constituent in soil should be at or below the California Department of Toxic Substances Control Screening Levels(DTSC-SLs)or the USEPA Regional Screening Level (RSL), whichever is more stringent. Thus, the selected laboratory should be able to perform analyses using the lowest commercially available and achievable RLs, to provide quantification of constituents for evaluation with respect to DTSC-SLs or RSLs. See discussion above. SPECIFIC COMMENTS 1. Section 3.0, Third Paragraph: The Work Plan states that "If contaminants of concern are not detected above the ESL or RSL, then no filrther action should be required. If constituents of concern are detected above the ESL or RSL and below the MCL, then no fuurther action should be required. If COCs are found above the MCL, then recommendations for jtrther action will be made".Please revise the Work Plan to address the following comments: a. As stated in General Comment No. 1 above, the Site is outside the jurisdiction of Region 2. Therefore, Region 2 ESLs are not applicable at the Site. The Work Plan should be revised to remove reference to ESLs. References have been removed. b. As stated in General Comment No. 2,groundwater at the Site is designated as suitable for municipal and domestic uses. Therefore, 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 n %4 +i1) CONDO