ARCHIVED REPORTS_XR0009220 - Laserfiche WebLink

Home Browse Search

Adddional Srte Assessment Report 4 The Southland Corporation,Store#17334,4501 North Pershing Avenue,Stockton,CA ^^ _ January 15, 1998 - street boxes (with watertight bolted lids)set In concrete Well construction details are shown on the drill logs in Appendix B Following installation,the wells were developed using a PVC bailer to remove fine-grained sediment from the well and sand pack Pnor to development activities, depth to water was measured relative to top-of- well-casing to determine the static water level in the wells Approximately eight casing volumes of water was extracted from each well and stored in a DOT-approved 55-gallon drum pending transportation and disposal The top of casing and nm of each well box was surveyed in December 1997, by Morrow Surveying for horizontal position and elevation relative to mean sea level datum using City of Stockton Benchmark#265 as a reference The resultant map is included in Appendix C Field notes from the well installation are included as Appendix D 3.5 Groundwater Monitoring and Sampling On December 19, 1997, depth to water in each well was measured to the nearest 0 01 foot from the top of the well casing using an ORS Environmental Equipment INTERFACE PROBE,Well Monitoring System Field data sheets are provided in Appendix D Subsequent to monitoring,at least four well volumes of water was bailed from each monitoring well to ensure stabilization of pH, electrical conductivity, and temperature The purge water was stored in a DOT- approved 55-gallon drum The groundwater samples were collected using disposable bailers,then transferred to 40-milliliter glass vials filled to zero headspace and acidified to a pH of 2 The samples were sealed using Teflon®-septum caps, labeled, placed on ice in an insulated container,and transported under chain-of-custody manifest to WEST in Davis, California The groundwater samples were analyzed for BTEX,TPH-G and MTBE using EPA methods 80201modfied 8015 The samples were additionally analyzed for TBA, MTBE, DIPE, ETBE and TAME by EPA method 8260 The groundwater sample from MW-2 was collected on September 24, 1997,as split sample from the same bailer with a field representative from the Clearwater Group, Inc, representing the former Cardlock _ Gasoline Station west of the site 4.0 RESULTS 4.1 Geology The relatively level site is located at an elevation of approximately 8 feet above mean sea level According to the California Division of Mines and Geology the site Is underlain by Quaternary alluvial deposits assigned to the Modesto Formation (Wagner etal, 1991) FLUOR DANIEL GTI