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ENVIRONMENTAL HEALTH DEPARTMENT
<br /> PQU.1" SAN JOAQUIN COUNTY
<br /> Donna K Unit Supervisors Heran,R.E.H.S.
<br /> Director304 East Weber Avenue, Third Floor Carl Borgman,R.E.H.S.
<br /> •: '- AI Olsen,R.E.H.S. Stockton, California 95202-2708 Mike Huggins, sonS.,R.D.T.
<br /> Douglas W.Willson,,R.E.H,S.
<br /> �9LiFo�a�P Program Manager
<br /> Laurie A.Corolla,R.E.H.S. Telephone: (209) 468-3420 Margaret Lagorio,R.E.H.S.
<br /> Program Manager Fax: (209) 464-0138 Robert McClellon,R.E.H.S.
<br /> SAY 3 �ark Ujrcellos,R.E.H.S.
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<br /> TRUST .OF MARY GARDELLA ESTATE OF JOE GARDUELLA
<br /> WINIFRED ALEXANDER DENNIS CASPE ESQ
<br /> 525 2"DST 2035 N PACIFIC AVE
<br /> SANTA CRUZ CA 95060 SANTA CRUZ CA 95060
<br /> RE: STEFANOS GASOLINE
<br /> 1419 E CHARTER WAY
<br /> STOCKTON, CA 95205
<br /> A meeting to review your site status was held at San Joaquin County Environmental Health
<br /> Division (EHD) conference room at 11 am on May 22, 2003. Present at the meeting were
<br /> John Lynch and Chris Palmer representing your consultant,Wright Environmental Services
<br /> Inc. (Wright), and Margaret Lagorio, Nuel C. Henderson,and Jeffrey Wong representing
<br /> EHD. The following is a summary of the discussion.
<br /> Three monitoring wells MW-1, MW-2, and MW-3, screened from 30 feet below surface
<br /> grade (bsg) to 50 feet bsg,were installed at the site in 1999. Elevated levels of
<br /> contamination in groundwater as high as 210,000 micrograms per liter(µg/1) of petroleum
<br /> hydrocarbons as gasoline (TPH-g), 7,800 µg/l benzene, and 500 µ/11,2-dichoroethane (1,2-
<br /> DCA), have been consistently detected in MW-2. Petroleum hydrocarbon contaminants
<br /> including 1,2-DCA and tert-butyl alcohol (TBA) have also been detected in MW-3,which is
<br /> located about 15 feet west of MW-2. Contaminants have not been detected in MW-1,which
<br /> is located about 20 feet east of MW-2. Groundwater flow gradient has been predominately
<br /> toward the east and to the southeast. The data log of the cone penetrometer boring CPT-1
<br /> located near MW-2,indicated the presence of a sand interval extending from about 30 feet
<br /> bsg to 36 feet bsg. Similarly, the data log of CPT-2,located about 160 feet southeast of
<br /> MW-2,indicated the presence of a sand layer extending from about 28 feet to about 32 feet
<br /> bsg. However, this same sand layer was not recorded in the 50-foot deep boring log of MW-
<br /> 4,which is located about 20 feet west of CPT-2. This difference may be indicative of the
<br /> presence of sand-filled former stream channels,which may exert preferential influences on
<br /> contamination plume migration.
<br /> Groundwater samples from MW-1,MW-4,MW-5, MW-6,and MW-7,all screened from 30
<br /> feet bsg to 50 feet bsg,have been continuously non-detect. However,grab groundwater
<br /> samples collected from CPT-2 at 60 feet had contaminant concentrations of 54 �tg/l TPH-g,
<br /> 4.4 Etg/11,2-DCA, and at 115 feet bsg 180 µg/l TPH-g, 3.3 Etg/l benzene,and 1.2 µg/1 1,2-
<br /> DCA. Likewise, grab water samples from CPT-1A about 15 feet south of MW-2 at 60 feet
<br /> bsg had concentrations of 59,000 µg/1 TPH-g and 210 Vg/1 benzene. The data log of CPT-
<br /> 2 indicated the presence of a sand unit from about 52 feet bsg to 57 feet bsg, and another
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