Laserfiche WebLink
Joe Aldridge <br /> Former Beacon# 12474 <br /> Page 3 of 3 <br /> EHD approves the well proposed for the area southwest of MW-16, but cannot <br /> approve the well proposed to be located southeast of MW-15. EHD <br /> recommends locating the latter well near MW-15 and CPT-3 to better <br /> characterize the findings from CPT-3 and have data comparable to the MW-15 <br /> data. If the new well is.impacted, there may be a technical justification for placing <br /> an additional well in the currently proposed location. <br /> EHD believes that the center of the site has not been adequately characterized; <br /> the core of the plume should be characterized and monitored to better estimate <br /> contaminant mass and to monitor plume response to any remedial actions or <br /> natural attenuation. This portion of the site includes the area south of VW-7, <br /> west of CPT-7, northeast of MW-16 and northwest of MW-15. At this time EHD <br /> is directing you to characterize the plume in this area and recommends <br /> installation of a monitoring well cluster (multiple single casing/bore hole wells) <br /> just northeast of the station building, close to, but not in, the existing <br /> underground storage tank pit. The recommended monitoring wells should be <br /> placed so that the first interface with ground water, the intermediate-depth zone, <br /> and the deeper zone are adequately represented. <br /> Currently MW-10 is the only monitoring well in the northwest corner of the site. <br /> The screened interval for this well is 50.5' to 70.5' bgs and TPHg was reported at <br /> 510 ug/I for the March 10, 2005 sampling event. This concentration is consistent <br /> with historical levels for this well and EHD considers this quadrant to be laterally <br /> and vertically undefined. Please address this concern by either proposing further <br /> investigation in this area or providing a technically based rationale as to why no <br /> further ground water investigation is needed here. <br /> Please continue to direct your submittals to Michael Infurna and you may call me <br /> at (209) 468-3454 should you have any questions or wish to discuss the site. <br /> Mr. Infurna can be reached by email at minfurnaCa)-sicehd.com. <br /> Donna Heran, RENS, Director <br /> Environ ental Health Department <br /> Michael J. Infurna Jr., Senior REHS Margar�LagorAio,TRHS. <br /> LOP / Site Mitigation Unit IV Supervisor <br /> MI/ <br /> c: CVRWQCB —James Barton, Sacramento. <br /> c: Horizon Envir. - G. Barker, 4970 Windplay Dr. #C5, EI Dorado Hills, 95762 <br /> c: SWRCB-CUF — Mark Owens, Sacramento. <br />