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Geosyntecl--' <br /> consultants <br /> # Location Comment Response to Comment <br /> 7 Section 3.2.2.1, The Work Plan adapts sampling procedures put forth in the 2018 Grab groundwater samples will be collected as <br /> Page 5, Groundwater Sampling Work Plan for Rough and Ready Island,which described in our response to Comment#4. The <br /> Paragraph 3 proposes either a disposable polyethylene bailer or clean polyethylene text in Section 3.2.1 paragraph 8 has been <br /> tubing and peristaltic pump to collect grab groundwater samples. Please edited to reflect the groundwater sampling <br /> describe the decision process for selecting either the bailer or peristaltic methodology. <br /> pump at a given sampling location. <br /> Furthermore,Appendix J in the 2018 Groundwater Sampling Work Plan <br /> references methods and procedures put forth in the United States <br /> Environmental Protection Agency's Groundwater Sampling and <br /> Monitoring with Direct Push Technologies(USEPA, 2005). This USEPA <br /> 2005 guidance document supports the use of a bladder pump to sample <br /> VOCs and SVOCs(see Table 3.2). Please justify why a bladder pump is <br /> not included as a preferred sampling method to collect grab groundwater <br /> samples at RRI,including the Site. <br /> Central Valley Water Board staff supports the use of either passive <br /> sampling or low flow sampling technologies to analyze VOCs in grab <br /> groundwater samples. Central Valley Water Board staff also advise <br /> against the use of groundwater sampling with peristaltic pumps for VOC <br /> analyses. Peristaltic pumps are known to promote degassing because of <br /> the vacuum pump which could cause a negative bias in sample results. <br /> Response to Comments on Draft and Revised Draft Investigation Work Plan 3 June 21,2022 <br /> Addendum—UST 817B <br />