Laserfiche WebLink
1260 Graphics Drive <br /> r Modesto Californsa <br /> 95351 <br /> _ 209 579 2221 <br /> Fax 209 579 2225 <br /> s fL <br /> .� A S S O C I A T E S I N C ( y 1y <br /> h <br /> January 26, 1998 <br /> Ms Mary Meays <br /> San Joaquin County Public Health Services <br /> Environmental Health Division <br /> PO Box 388 <br /> Stockton, CA 95201-0388 <br /> Subject Groundwater Monitoring Report, October through December 1997, 26056/26080 <br /> Thornton Road, Thornton, CA, Site Code 1864 <br /> Ms Meays <br /> This letter report summarizes field activities conducted during the Fourth Quarter 1997 by ATC <br /> Associates Inc at the subject site (Figure 1) On August 20, 1997 ATC Associates purchased <br /> • certain assets of Smith Technology <br /> BACKGROUND <br /> On September 6, 1989, three underground gasoline storage tanks were removed at the project site <br /> by Western Meter Service of Stockton, California Soil samples were collected beneath each tank <br /> 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 concentrations of petroleum hydrocarbons in the tank pit soil <br /> samples, further investigation was required by San Joaquin County Public Health Services, <br /> Environmental Health Division (PHS/EM) <br /> In a two-phased approach beginning on November 1, 1990, RESNA Industries Inc personnel <br /> advanced six soil borings (NMI through MW6) to depths ranging from 27 to 30 feet below grade <br /> at the project site to accomplish the following 1) define the lateral and vertical extent of <br /> hydrocarbon impacted soils, 2) determine soil stratigraphy, and 3) install groundwater monitoring <br /> wells within the uppermost aquifer in order to assess groundwater quality The boring/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 /> w 1943261guart1yl4gr-1997 doc <br /> 1 <br />