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CLEARWATER <br /> G R O U P, I N r�C <br /> Enviror[tnen al Servzces <br /> QUARTERLY GROUNDWATER MONITORING RWt3RT <br /> FOURTH QUARTER 1997 <br /> Ruiz Grocery, <br /> 4491 West Durham Ferry Road,Tracy, CA <br /> CGI Project D-107 <br /> January 5,1998 <br /> BACKGROUND <br /> Two gasoline USTs and dispensers were removed from the site in 1988 Seven monitoring wells (NW-1 <br /> through MW-7), one groundwater recovery well (RW-1), four soil vapor extraction wells {i -1 <br /> through VW-4), and two air sparge wells (SW-1 and SW-2) have been installed at the site A domestic <br /> well (DW), screened in a deeper water bearing zone, has also been installed at the site The extent of <br /> soil and water contamination has been delineated Pilot testing has been completed and a ret edial <br /> action plan prepared based on results <br /> The work presented here was conducted as part of scheduled quarterly groundwater monitoring a$ <br /> requested by the San Joaquin County Public Health Services / Environmental 11ealth Divisum <br /> (SJCPHS/EHD) All work was conducted in accordance with Clearwater's Field Procedures attacked <br /> GROUNDWATER MONITORING FIELD ACTIVITIES <br /> Date of field activities 11/14/97 <br /> Wells monitored/sampled MWA to MW-7 and the domestic well (DW) <br /> Analytes tested TPHg,BTEX, and MTBE <br /> Analytical methods EPA Methods 8015/8020 (modified) <br /> Laboratory American Environmental Network, Inc of Pleasant Hill, CA <br /> Remarks None <br /> GROUNDWATER MONITORING RESULTS <br /> Depth to water 1180 to 13 69 feet below ground surface(bgs) <br /> Flow direction/gradient Overall, north at 0 008 ft/ft <br /> SPH - wells/thicknesses Sheen in MW-1 and MW-2 <br /> TPHg concentration range <50 gg/L (DW,MW-4,5,6, and 7) to 51,000 gg/L (MW-1) <br /> Benzene concentration range <0 5 gg/L (DW,MW-3,4,5, 6, and 7) to 1,900 gg/L (MW-2) <br /> MTBE concentration range <5 0 gg/L (DW,MW-3,4, 7) to 2,500 gg/L (MW-2) <br /> Remarks Slight groundwater mounding in vicinity of site producing divergent flow pattern Flow <br /> direction is consistent with those typically observed at the s;te (to the northwest - northeast), Low <br /> levels of hydrocarbon contamination have been detected in the domestic well for the first time The <br /> domestic well is not used to supply drinking water and signs indicating the water is non-potable have <br /> been posted <br /> PROJECT STATUS <br /> Clearwater has submitted a cost pre-approval to the UAderground Storage Tank Clean-up Fund for <br /> tasks associated with installation, start-up, operation and 1161 antenance of the remediation system, on <br /> behalf of Ruiz Grocery Cost pre-approval is expeeti�-d by the end of January 1998 Quarterly <br /> groundwater monitoring will continue,as requested by SJCPHS/EHD <br /> i <br /> 520 Third Street,Suite 10.1 � Oakland,California 91607 - 'Telephone 510-893-5160 - Fa,< 510-393-59.17 <br /> I <br />