Laserfiche WebLink
ENVIRONMENTAL HEALTH DEPARTMENT <br /> SAN JOAQUIN COUNTY <br /> Unit Supervisors <br /> Donna K.Heran,R.E.H.S. Third Floor <br /> Carl Borgman,R.E.H.S. <br /> uQi: I Director 304 East Weber Avenue, Mike Huggins,R.E.H.S.,R.D.I. <br /> Al Olsen,R.E.H.S. Stockton, California 95202-2708 Douglas W.Wilson,R.E.H.S. <br /> • �. P Program Manager Telephone: (209) 468-3420 Margaret Lagorio,R.E.H.S. <br /> 4C6F'ORa Laurie A.Cotulla,R.E.H.S. Robert McClellon,R.E.H.S. <br /> Program Manager Fax: (209) 464-0138 Mark Barcellos,R.E.H.S. <br /> DON RODGERS JUNIUS MCKELVEY <br /> 11190 S UNION ROAD 515 CHARTER WAY <br /> MANTECA CA 95336 STOCKTON CA 95206 <br /> RE: The Transmission Shop AUG 1 2Q03 <br /> 515 W. Charter Way <br /> Stockton CA 95206 <br /> San Joaquin County Environmental Health Department (SJC/EHD) has reviewed <br /> "Additional Assessment and Remedial Feasibility Test Report" (Report) dated <br /> June 18, 2003, and the "Second Quarter 2003 Status Report" dated July 9, 2003 that <br /> were submitted on your behalf by Shaw Environmental, Inc. (Shaw) and has the <br /> following comments. <br /> The report documents site fieldwork that was completed in March and April 2003: Two <br /> shallow (MW-2R and MW-3R) and one dual completed (MW-4RS and MW-4RD) <br /> monitoring wells were installed to further investigate the lateral and vertical extent of the <br /> contamination at this site. Soil samples for analysis were collected during the drilling of <br /> the boreholes for the wells. Feasibility testing was completed to investigate remedial <br /> options to complement the currently operating soil vapor extraction (SVE) system. <br /> Specifically, a pumping test and an air sparge test were performed. <br /> Analytical results from the soil samples were positive for petroleum hydrocarbons in <br /> boring MW-4R, from 30 feet below surface grade (bsg) to total sample depth of 70 feet <br /> bsg, with the highest concentrations at 30 feet. Samples from the other two borings <br /> were-non-detect for all constituents analyzed. The new wells were developed and <br /> sampled on April 10, 2003. Positive analytical results in groundwater samples were <br /> obtained from all wells, though concentrations in the lateral wells were low. <br /> Concentrations in both MW-4RS and MW-4RD were high, indicating that the vertical <br /> extent of the contamination at this site has not been defined. The deeper well, <br /> MW-4RD, had 21,000 micrograms per liter (µg/l)total petroleum hydrocarbons (TPH) as <br /> gasoline and 320 µg/I benzene. <br /> The report states that the predominant historical groundwater flow direction at this site <br /> has been to the northwest. SJC/EHD does not agree with this statement. Review of the <br /> groundwater monitoring reports that have been submitted on behalf of this site indicate <br /> that the predominant flow direction has been towards the northeast, with some variation. <br /> For the period from September 2001 thru August 2002 the direction was reported as <br /> varying from southwest to northwest. In November 2002 it was towards the east, and in <br /> February of 2003 it was towards the south. A licensed surveyor surveyed the recently <br />