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�C DPQ D^------ <br /> CLEARWATER <br /> UkOT- 11 I \ L <br /> Ent irunmental Servres <br /> QUARTERLY GROUNDWATER MONITORING REPORT <br /> THIRD QUARTER 1997 <br /> Ruiz Grocery, <br /> 4491 West Durham Ferry Road, Tracy, CA <br /> August 18, 1997 <br /> CGI Project D-107 <br /> BACKGROUND <br /> Two gasoline USTs and dispensers were removed from the site in 1988 Seven monitoring wells (MW-1 <br /> through MW-7), one groundwater recovery well (RW-1), four soil vapor extraction wells (VW-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 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 remedial <br /> action plan prepared based on results <br /> The work presented here was conducted as part of scheduled quarterly groundwater monitoring as <br /> requested by the San Joaquin County Public Health Services / Environmental Health Division <br /> (SJCPHS/EHD) All work was conducted in accordance with Clearwater s Field Procedures attached <br /> GROUNDWATER MONITORING FIELD ACTIVITIES <br /> Date of field activities 7/24/97 <br /> Wells monitored/sampled MW-1 to MW-7 except MW-4, 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 MW-4 could not be located due to telephone line trenching <br /> GROUNDWATER MON ORING RESULTS <br /> Depth to water 1180 to 13 69 feet below ground surface (bgs) <br /> Flow direction/gradient Southwest at 0 0046 ft/ft <br /> SPH - wells/thicknesses none <br /> TPHg concentration rang <50 Eig/L(DW,MW-3,5, 6, and 7) to 59,000 4g/L (MW-1) <br /> Benzene concentration r ge <0 5 pg/L(DW,MW-3, 5,6, and 7) to 1,400 gg/L (MW-2) <br /> MTBE concentration range <5 0 gg/L (DW, MW-3) to 930 dig/L(MW-2) <br /> Remarks Groundwater flow direction (to the southwest) observed this quarter <br /> and in the second quarter of 1997 is inconsistent with the flow directions <br /> typically observed at the site (to the northwest - northeast) The <br /> change in flow direction may be the result of local agricultural water <br /> uses However, groundwater elevations are generally consistent with <br /> previous observations and the dissolved-phase plume remains <br /> delineated The domestic well remains free of detectable <br /> contamination <br /> PROJECT STATUS <br /> • Clearwater will submit a cost pre-approval to the Underground Storage Tank Clean-up Fund for tasks <br /> associated with installation, start-up, operation and maintenance of the remediation system, on behalf <br />