ARCHIVED REPORTS_XR0006498 - Laserfiche WebLink

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I CLEARWATER G n O U P, I N C Enurrortmen[a! Services natural attenuation remedial strategy In a letter dated March 22, 1993 San Joaquin County staff denied this request, and requested the submittal of a workplan for the installation of additional monitoring wells and the completion of remediation pilot testing I In response to the County's request, E-Z Serve staff prepared and submitted the technical specifications of additional activity, consisting only of the details of additional well installation The workplan requested deferment of pilot testing until the results of the additional well installation came available Quarterly sampling continued I I Following the receipt of responses to competitive bidding, E-Z Serve selected Hydro-Environmental Technologies, Inc for the installation and sampling of the described additional monitoring wells The results of additional investigation were consistent with previous results, and were submitted to the County in a report dated January 20, 1994 In accordance with San Joaquin County requirements, quarterly sampling continued Brown and Caldwell (B &C) was subsequently retained by E-Z serve to satisfy County requirements for remedial feasibility testing Following the exchange of technical information with County Ntaff during test preparation a soil vapor extraction test was completed and documented in a B & C report dated August 29, 1995 County staff determined the results of the test to be inconclusive and requested additional evaluation In accordance with the Counties wishes a workplan for this additional testing was prepared and submitted by Brown and Root Environmental (November 28, 1995) This workplan was approved by the County in a letter dated December 11, 1995 The additional pilot testing was not completed File documentation indicates that the basis for the decision was the State Board directive in late December, 1995 that referenced the results of the Lawrence Livermore study regarding low-risk hydrocarbon contamination sites r Activities to date have consisted exclusively of quarterly groundwater monitoring The results of the sampling events over the past several years have demonstrated a steady decline in contaminant concentrations Based on this trend, Clearwater proposed, during a conversation with County staff in May, 1998, that site closure may now be appropriate The County concurred, and stated that a petition , for case closure could be submitted, but requested that one additional round of groundwater sampling be performed and evaluated The County also requested that during this final round of sampling that groundwater samples be tested for concentrations of fuel additives Iby EPAM 8260 Page II � ,11