Laserfiche WebLink
4 <br /> California Regional Water Quality Control Board <br /> Central Valley Region <br /> .�r <br /> Robert Schneider, Chair <br /> Alan C.Lloyd,Ph.D. Arnold Schwarzenegger <br /> Secretary for Sacramento Main Office Governor <br /> Environmental Internet Address: http://www.swrcb.ca.gov/rwgcb5 <br /> Protection 11020 Sun Center Drive#200 Rancho Cordova,CA 95670-6114 <br /> Phone(916)464-3291 <br /> 29 April 2005 I(IUy1 �D <br /> Ms. Kerry Heckman MAY 0 2 ?005 <br /> Connell Tire E"RQNENT HEALTH <br /> 2211 North Wilson Way pERP✓1T/SERVICES <br /> Stockton, California 95205 <br /> DOCUMENT REVIEWS,RIVER CITY PETROLEUM AND CONNELL MOTOR LIFT TRUCK, <br /> 2211 NORTH WILSON WAY, STOCKTON,SAN JOAQ17IN COUNTY <br /> I reviewed the Quarterly Report—Fourth Quarter 2004 (Report),received 8 February 2005, and the Monitoring <br /> Well Installation Report—Site Assessment Work Plan (Workplan),received 7 March 2005,prepared on your <br /> behalf by your consultant Advanced GeoEnvironmental,Inc. (AGE). The Report provides the results of quarterly <br /> groundwater sampling conducted on 20 December 2004,and the startup and monitoring of the soil vapor <br /> extraction(SVE) system in the underground storage tanks(USTs) source area. The Workplan provides a <br /> description of well installation in December 2004 and results of soil and groundwater analyses for monitoring <br /> wells MW-36 and MW-37 (enclosed Figure 2). The Workplan proposes installation of five continuous multi- <br /> chamber tubing(CMT)monitoring wells to complete lateral and vertical definition of the petroleum hydrocarbon <br /> groundwater plume(Figure 2). <br /> The Report shows that groundwater flow direction over the last four quarters varied from north to east in the <br /> shallow aquifer zone (60 feet below ground surface, or bgs?, and southeast to southwest in the middle aquifer <br /> zone(100 feet bgs). Depth to water(approximately 55 feet)rebounded by up to 9 feet since the third quarter of <br /> 2004, when shallow aquifer zone wells MW-1 through MW-17 were dry. This quarter only MW-1 was dry, <br /> reportedly silted up fr. . ")to 60 feet below ground surface(bgs). The max -lum contaminant concentrations <br /> reported for groundwater were: Total Petroleum Hydrocarbons(TPH)as Gasoline(TPHg, 20,000 gg/L),Benzene <br /> (B,2,600 ti,&L),Toluene(T, 190 gg/L),Ethylbenzene(E, 570 gg/L),Xylenes(X, 3,9000 µg2),tert-Butyl <br /> Alc-' . BA, 130 µg/L), and 1,2-dichloroethane (1,2-DCA, 250 gg/L). With the exception of 1,2-DCA, all <br /> m:.. _...um contaminant concentrations reported this quarter were from previously dry MW-7. Those samples <br /> showed one to two orders of magnitude concentration increase over the maximum concentrations in the third <br /> quarter of 2004. <br /> The Report also discussed the startup of the interim soil vapor extraction(SVE)system in the USTs source area. <br /> Approximately 1,400 gallons of gasoline were removed by the SVE system between 10 November and <br /> 31 December 2004. AGE concludes in the Report that additional investigation to the north is needed to define <br /> the vertical and lateral extent of petroleum hydrocarbon contamination. <br /> The Workplan describes the well installations on 3 through 13 December 2004 and the 18 December 2004 <br /> groundwater sampling results for MW-36(screened 145 to 150 feet bgs) and MW-37 (screened 195 to 200 feet <br /> bgs); both wells are located near the source area of the USTs. Equipment breakdowns and flowing sands <br /> problems caused delays in installation of the two monitoring wells. <br /> California Environmental Protection Agency <br /> �a Recycled Paper <br />