Laserfiche WebLink
PUBLIC EALTH SER CES Aau,N <br /> SAN JOAQUIN COUNTY <br /> ENVIRONMENTAL HEALTH DIVISION <br /> Ernest M. Fujimoto, M..D., M.P.H., Acting Health Officer <br /> P. O. Box 388 Stockton, CA 95201-038&:�� <br /> 304 E. Weber Ave., Third Floor <br /> 209/468-3420 <br /> BOB DENINNO <br /> SOUTHLAND CORPORATION MLED NIAR 2 71996 <br /> 19033 WEST VALLEY HIGHWAY, SUITE D-104 <br /> KENT WA 98032 <br /> RE: 7-Eleven Store #20304 SITE CODE: 1409 <br /> 455 West Grant Line R4d <br /> Tracy CA 95376 <br /> San Joaquin County Public Health Services, Environmental Health Division <br /> (PHS/EHD) has completed review of the "NPDES Permit Quarterly Monitoring <br /> Report" dated January 8, 1996 and the "Fourth Quarter 1995 Monitoring and <br /> Sampling Report" dated January 22, 1996, both of which were prepared by <br /> Groundwater Technology Inc. (GTI). PHS/EHD has also reviewed GTI's <br /> correspondence dated February 29, 1996. PHS/EHD has prepared the following <br /> comments for your consideratio' n. <br /> The quarterly report prepared for. compliance with National Pollution Discharge <br /> Elimination System (NPDES) permit #CA0082929, Order #92-15013, indicated that <br /> the groundwater extraction sys"te'm began operation on October 8, 1995 and that <br /> through the period ending December 13, 1995, 33,784 gallons of contaminated <br /> groundwater was treated and discharged to Sugar Cut Slough. The extraction rate <br /> achieved, less than 1 gallon per minute, and the drawdown measured indicated <br /> that groundwater extraction may not be a viable methodology to enhance the <br /> availability to access contaminated soil, so that vapor extraction may be <br /> implemented and source reduciion achieved. <br /> PHS/EHD recommends that the selected remediation methodology be re-evaluated <br /> based on current recovery rates.: It is PHS/EHD's hope that the most effective <br /> remedial strategy be implemented so that site closure will be warranted. <br /> The groundwater monitoring and' sampling report included the results of the <br /> December 13, 1995 sampling event which continued to evidence significant <br /> groundwater contamination. During the period between September 19 and <br /> December 13, the depth to groundwater rose over a foot, with the average depth <br /> to groundwater, of approximately 3.75 feet below ground surface. The <br /> concentrations reported were elevated, with the suggestion of plumb migration, <br /> based on the concentrations observed in monitoring well, MW5. The groundwater <br /> monitoring and sampling reports which are submitted in the future should include a <br /> summary and evaluation of remedial progress. <br /> A Division of San Joaquin County Health Circ Services <br />