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San Joaquin County DIRECTOR
<br /> Environmental Health Department Donna Heran, REHS
<br /> 600 East Main Street ASSISTANT DIRECTOR
<br /> Laurie Cotulla, REHS
<br /> Stockton, California 95202-3029
<br /> " PROGRAM COORDINATORS
<br /> ~ Margaret Lagorio, RENS
<br /> c � ' `P Website: WWW.sjgov.org/ehd Robert McClellon, REHS
<br /> Rhone: (209) 468-3420 .teff Carruesco, REHS, RDJ
<br /> Fax: (209) 464-0138 Kasey Foley, REHS
<br /> September 23, 2009
<br /> Mr, Allen Fetters
<br /> Ripon Farm Service Incorporated
<br /> 3705 Portsmouth Circle
<br /> North Stockton, California 95219
<br /> Subject: Ripon Farm Service Incorporated
<br /> 932 South Highway 99 (Formerly 22871 South Highway 99)
<br /> Ripon, California 95366
<br /> The San Joaquin County Environmental Health Department's (EHD) has reviewed Vapor Intrusion
<br /> Investigation Report, dated June 22, 2009, prepared and submitted by Advanced
<br /> GeoEnvironmental, Inc. (AGE) on your behalf for the above-subject site. The report presented
<br /> results from collecting soil gas samples from three on-site borings, each advanced to
<br /> approximately five-and-a-half feet below surface grade. The soil gas samples were analyzed for
<br /> chemicals of concern that included total petroleum hydrocarbons (TPH) quantified as gasoline
<br /> (TPH-g), benzene, toluene, ethyl benzene, and total xylenes (BTEX), methyl tertiary-butyl ether
<br /> (MTBE), ethyl tertiary-butyl ether (ETBE), tertiary-amyl methyl ether (TAME), tertiary butyl alcohol
<br /> (TBA), di-isopropyl ether (DIPS), 1,2-dichloroethane (1,2-DCA), 1,2-dibromoethane (EDB), and
<br /> isopropyl alcohol (IPA).
<br /> AGE reported that TPH-g was detected in soilq as collected from boreholes VP-1, VP-2, and VP-3
<br /> at 71,000 micrograms per cubic meter (lag/m ), 64,000 lag/m3, and 54,000 lag/m3, respectively;
<br /> and toluene was detected at 8,300 lag/m3, 6,700 pg/m3, and 5,900 lag/m3, respectively. The soil
<br /> gas concentrations for TPH-g exceeded the Environmental Screening Level (ESL) of 29,000
<br /> lag/m3 for commercial property, established by the San Francisco Bay Regional Water Quality
<br /> Control Board; however, the soil gas concentrations for toluene did not exceed the ESL of
<br /> 180,000 lag/m3 for commercial property.
<br /> AGE calculated the Risk and Hazard Quotient for TPH-g in soil gas using the Johnson and
<br /> Ettinger Vapor Intrusion Model. The carcinogen risk for TPH-g was calculated to be zero, and the
<br /> summation of hazard was calculated to be 1.9E-04, well below the action level of 1.0. Based on
<br /> these results, AGE recommended no further action at this site.
<br /> The EHD concurs with the recommendation by AGE and directs the submittal of a comprehensive
<br /> site closure summary by December 1, 2009; however, the EHD has discussed the contents of the
<br /> soil-gas report with the Central Valley Regional Water Quality Control Board (CVRWQCB).
<br /> Concerns by the EHD and the CVRWQCB are presented below:
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