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<br /> ENVIRONMENTAL AL 14 DEP. IR.TMENT
<br /> SAN JOAQUIN COUNTY
<br /> Unit Supervisors
<br /> Dorsna K:Heran,R.E.H.S. r Carl Borgman,R.E.H.S.
<br /> Director £04 East Weber Avenue, T1l1XCl f"IdOr Vfike Huggins,R.E.H.S.,
<br /> • Al Olsen,R.E.H.S. Stockton, California 9520?-Z7�$ Douglas W.Wilson,R.1`.11.S.
<br /> . Program Manager Fele hone: (209) 468-3420 Margaret 1,agario,R.L.H.S.
<br /> Laurie A.Cotulla,R.E.H.S. p Robert McClellon,R.E.H.S.
<br /> Progran,Manager Fax: (209) 464-01.38 M<,ck Barcellos,R.E.H.S.
<br /> ALLEN FETTERS SEP 14 2004
<br /> RIPON FARM SERVICE INC
<br /> 3705 PORTSMOUTH CIRCLE
<br /> NORTH STOCKTON CA 95219
<br /> RE: Ripon Farm Service Inc. SITE CODE: 1605
<br /> 22871 South Highway 99
<br /> Ripon, California 95366
<br /> San Joaquin County Environmental Health Department (EHD) has reviewed the Guarteriv
<br /> Re port — First Quarter 2004' prepared and submitted on May 1�', 2004, by As,�ar:ced
<br /> GeoEnvironnzental, Inc. (AGE) on your behalf for the above-referenced site_ In this report,
<br /> AGE documents that in January 2004 the soil vapor extraction (SVE) system
<br /> malfunctioned and operations ceased_ Results from a soil vapor sample collect.-a' on
<br /> December 22, 2003 indicated that total petroleum hydrocarbons as gasoline was present at
<br /> a concentration. of 34 micrograms per liter, and non-detect results were reported for methyl
<br /> tertiary-butyl ether, benzene, toluene, ethyl benzene, and total xylenes. Therefore,the SVE
<br /> system was not restarted. Before taking the SVE system permanently off-line, EHD directs
<br /> you to conduct a rebound test on the SVE system and report the results from the system
<br /> and from each monitoring well. Submit the results from the SVE rebound test to EHD by
<br /> November 10, 2004.
<br /> AGE has recommended consideration of case closure for this site. However, EHD has
<br /> concerns regarding the diesel contamination found in soil boning.samples CB1, CB2, CB3,
<br /> and CB5 at twenty feet below surface grade, and the high concentrations of 1,2-
<br /> dichioroethane (1,2-DCA) found in groundwater samples during the quarterly groundwater
<br /> monitoring events. Groundwater contaminated by 1,2-DCA has not been delineated in the
<br /> west and south directions at this site. Therefore, EHD cannot support a recommendation
<br /> for site closure at this time. Additional information is needed. PIease provide a work plan
<br /> to EHD by November 3, 2004, to assess the lateral extent of 1,2--DCA contamination at this
<br /> site. Upon completion of this assessment, provide mass estimates for diesel and 1,2-DCA
<br /> at this site, along with a fate and transport model for both of these substances to assist in
<br /> site closure consideration. Submit the results from the proposed site assessment, the mass
<br /> estimates for diesel and 1,2-DCA, and the fate and transport models to EHD within six
<br /> weeks of completing the fieldwork for additional site assessment.
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