Laserfiche WebLink
1117 Lone Palm Avenue <br /> Suite B <br /> Modesto CA 95357 <br /> 209 579 2221 <br /> OV %TC I Fax 209 579 2225 <br /> i <br /> January 31, 2000 <br /> Mr Harlin Knoll <br /> San Joaquin County Public Health Services <br /> Environmental Health Division <br /> 304 E Weber Ave . Fourth Floor <br /> Stockton, CA 95201-0388 <br /> Subject Groundwater Monitoring Report, October through December 2999, 26056126080 <br /> Thornton Road, Thornton, CA, Site Code 1864 <br /> Mr Knoll <br /> This letter report summarizes field activities conducted during the Fourth Quarter 1999 by ATC <br /> Associates Inc at the subject site (Figure 1) <br /> BACKGROUND <br /> On September 6, 1989, Western Meter Service of Stockton, California removed three <br /> underground gasoline storage tanks at the project site Soil samples were collected beneath each <br /> tank and the associated piping Soil samples collected from beneath two of the tanks contained <br /> moderate to high levels of ethylbenzene and xylenes (1 2 to 70 parts per million [ppm]) as well as <br /> total petroleum hydrocarbons as gasoline (TPHg) at 470 to 830 ppm <br /> Due to the presence.of elevated,=ncentraitions of petroleum hydrombons1 in the tank pit soil <br /> samples, further investigation wets requited by San Joaquin County Public Health Services, <br /> Environmental Health Div*ion,(PHS/EHD) <br /> In a two-phased approach beguming on November 1, 1990, RESNA Industries Inc personnel <br /> advanced six soil borings(N1W1 threu `W6) to depths ranging from 27 to 30 feet below grade <br /> at the project site to accomplish 4he,following 1) define the lateral and vertical extent rof <br /> hydrocarbon impacted soils, 2) determine soil stratigraphy, and 3) installgmundwater monitoring <br /> wells within the uppermost aquifer in order to assess groundwater quality The bonng/well <br /> locations are plotted on Figure 2 Field methodology and analytical results are discussed,in detail <br /> in RESNA's Interim Problem Assessment Report, dated January 13, 1992 <br /> The site's station building and garage were demolished in December 1994 to facilitate corrective <br /> action activities including,,the removal of hydrocarbon contaminated soil which was present <br /> beneath the station building The demolition of the station building was requested in PHS/EHD <br /> correspondence dated July 7, 1994 A required demolition asbestos suFvey conducted,previously <br /> on the station building determined the presence of asbestos containing rtenals - E T <br /> ri%25921quart1yl4gr-1999 doe 1 <br />