Laserfiche WebLink
x� <br /> ENVIRON"WENTAL HEALTH` kPARTMENT <br /> SAN JOAQUIN COUNTY <br /> Donna K. Heran, R.E.H.S. Unit Supervisors <br /> Director 304 East Weber Avenue,Third Floor Cart Borgman,R.E.H.S. <br /> Laurie A. Cotulla, RX.H.S. Stockton, California 95202-2708 Mike Huggins, R.E.H.S., R.D.I. <br /> • c, p Program Manager Douglas W. Wilson, R.E.H.S, <br /> Q<<'Fgi Telephone: (209)468-3420 Margaret Lagorio,R.E.H.S. <br /> Fax: (209) 464-0138 Robert McClellon, R.E.H.S. <br /> Website:www.sjgov.org/ehd/ Jeff Carruesco, R.E.H.S. <br /> DAVID ATWATER NAR 3 12006 <br /> FUEL STOPS LAND & DEVELOPMENT LLC <br /> P O BOX 1207 <br /> STOCKTON CA 95201 <br /> RE: Lathrop Gas &Food Mart SITE CODE: 1507 <br /> 14800 Highway 99 RO: 0199 <br /> Manteca,CA 95336 <br /> San Joaquin County Environmental Health Department (EHD) has reviewed Site Conceptual <br /> Model (SCM) dated October 31, 2005, prepared by Advanced GeoEnvironmental, Inc. (AGE) on <br /> your behalf. In this report AGE presented the case that petroleum hydrocarbon contamination <br /> discovered in two soil samples collected near dispensers D1 and D4 during excavation and <br /> upgrade of the underground storage tank (UST) dispenser and piping system in January 2003, <br /> was the result of residual hydrocarbon concentrations from a previous release of petroleum <br /> hydrocarbons prior to 1988. EHD issued a no further action letter in December 1998 for the <br /> original contamination release following site remediation. <br /> AGE recommends no further action for future investigation at this site and to support this <br /> recommendation,AGE presented the following information: <br /> • Dispenser D1 was the only location where significant concentrations of petroleum <br /> hydrocarbons in soil were detected during UST system upgrades in 2003. Also, <br /> hydrocarbon contamination was found only in boring B1, located adjacent to D1, during <br /> a site investigation in August 2004 involving the advancement of three soil borings. <br /> Therefore, AGE concluded that dispenser Di was the source of contamination and the <br /> extent of remaining contaminants was localized. <br /> • Groundwater and soil samples collected from BI contained total petroleum hydrocarbons <br /> as gasoline (TPH-g) that was identified as degraded gasoline (the product of aging) by <br /> Cal Tech Environmental Laboratories,the laboratory that analyzed the samples. <br /> • Methyl tertiary-butyl ether (MTBE) and 1,2-dichloroethane (1,2-DCA) were also <br /> detected in groundwater samples collected from 131 at concentrations of 18 micrograms <br /> per liter (µg/L) and 2.7 µg/L, respectively. These concentrations are comparable to <br /> MTBE and 1,2-DCA concentrations remaining onsite during the site closure in 1998. <br /> (Monitoring well MW-2, formerly located approximately 20 feet west/southwest of B1 <br /> and 15 feet southwest of DI, contained 5.7 µg/L 1,2-DCA and 16 pg/L MTBE during the <br /> final quarterly monitoring event in November 1997. Also, soil and groundwater samples <br /> collected in 2004 from boring 132, located adjacent to the former site of MW-2,were non- <br /> detect for all chemicals of concern.) <br />