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08 March 2005 AGE-NC Project No. 02-0962 Page 2 of 9 grade(bsg), based on the map titled Lines of Equal Depth to Groundwater Spring 1996 published by the San Joaquin County Flood Control District and Water Conservation District(FCD&WCD). However, the depth to ground water encountered during the drilling of well MW-1 was approximately 47 feet bsg, and the depth to water taken by AGE field personnel was measured at approximately 49 feet bsg. The map titled Lines of Equal Elevation of Groundwater Spring 1996, also published by the FCD&WCD, shows the property to be in an area where ground water flows toward the south and southwest, but this may be modified by changing recharge and discharge patterns. Ground water is considered to be of beneficial use and is used for domestic,industrial and commercial purposes. 2.2 UNDERGROUND STORAGE TANK REMOVAL Based on conversations conducted by J.H. Kleinfelder & Associates (JHK) with former property owner Tom Tucker and San Joaquin County Environmental Health Department(EHD)personnel, two 1,000-gallon USTs were removed from the site in 1984 or 1985. No further information regarding the excavation and removal of the USTs is available to AGE at this time. 2.3 SITE ASSESSMENT ACTIVITIES On 16 October 1985,JHK advanced one soil boring to a depth of 65 feet bsg for the installation of a ground water monitoring well(MW-1;Figure 2).The well was constructed using 2-inch diameter polyvinylchloride(PVC)casing with a 0.020-inch slotted screen installed from 35 feet to 65 feet bsg. Number 2 Monterey sand was installed to approximately 1 foot above the screened interval,with a bentonite seal above the sand pack. Soil samples were collected at 5-foot intervals from 10 feet to 45 feet bsg and transported under chain of custody to California Water Labs(CWL)for analysis.Soil samples taken at 35 feet(B1-35) and 40 feet bsg(B1-40)were analyzed for: • Benzene, toluene, ethylbenzene, and total xylenes (BTEX), chlorobenzene, 1,2- dichlorobenzene, 1,3-dichlorobenzene, and 1,4-dichlorobenzene by EPA Method 602; and • Total petroleum hydrocarbons (TPH)and total lead. Benzene was detected in samples BI-35 and BI-40 at concentrations of 13.3 micrograms per kilogram (µg/kg: parts per billion) and 296 µg/kg,respectively. Xylenes were detected in samples B1-35 and B1-40 at concentrations of 282 µg/kg and 27,000 µg/kg,respectively. Toluene was detected in sample BI-35 at a concentration of 120 µg/kg.Ethylbenzene was detected in sample B 1-40 at a concentration of 6,900 µg/kg. Advanced GeoEnvironmental,Inc.