ARCHIVED REPORTS_XR0007688 - Laserfiche WebLink

Home Browse Search

URS . Mr Harlin Knoll Page 6 San Joaquin County Environmental Health Department ARCO 2093 February 24, 2005 SENSITIVE RECEPTORS During the fourth quarter of 2004, URS performed a sensitive receptor survey at the site to identify the locations of water wells (municipal, domestic, and agricultural) within 2,000 feet and surface water bodies, schools, and other receptors within 500 feet of the site The survey consisted of review of Department of Water Resources (DWR) San Joaquin District office well information, contacting the City of Tracy Public Works Water Resources Division (CTPWWRD), the local water purveyors, to ascertain the location of and pertinent well construction information for nearby wells, and a 500-foot field reconnaissance to locate and/or confirm the presence of wells or other sensitive receptors DWR records identified 14 wells within 2,000 feet of the site The records included information about 13 domestic wells and one well of unknown use The closest identified well is approximately 200 feet north-northeast of the site and is located at the Chevron gasoline station across Tracy Blvd This well is screened between 123 feet and 131 feet deep The results of the DWR well search are provided in Table 4, and the well locations are shown on Figure 1 URS contacted CTPWWRD to ascertain whether they operated any wells in the vicinity of the ARCO site According to Mr Steve Bayley with CTPWWRD, the city does not own or operate any production wells in the vicinity of the site On December 6, 2004, URS performed a 500-foot reconnaissance to identify and/or verify the location of wells, water bodies, and schools During the site reconnaissance, URS contacted nearby well owners to ascertain whether the numerous identified domestic wells were currently in use According to Jennifer Trujillo, daughter of Joe Francesco (10935 W Clover Rd property owner), all wells identified along W Clover Road are currently used for domestic water supply No schools, water bodies, or other sensitive receptors were identified CONCLUSIONS AND RECOMMENDATIONS The following information fulfills the RWQCB Central Valley Region's outstanding requirements for site closure The RWQCB checklist for No Further Action at UST sites is included as Attachment L • Active remediation has removed a cumulative mass of 3,617 pounds of TPHg and approxi- mately 10 6 pounds of benzene from the vadose zone In addition, approximately 1,000 yards of contaminated soil have been removed from the site • Mass estimates indicate that less than 1 Ib of hydrocarbons remains beneath the site • Trend analysis of contaminants in site groundwater indicates that hydrocarbon concentrations will continue to decrease to below detection limits within the next several years i K IWprocessU5 BP ARC01020931Closure Report\Draft of 2093 Closure Report doe