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EXECUTIVE SUMMARY In accordance with Upgradient Environmental Consultants proposal 98006, which was preapproved by the State UST Cleanup Fund on February 25, 1998,Upgradient performed monitoring activities at the former Conrady Service Station in Stockton, California in June and July, 1998 In addition, in accordance with Upgradient's May 5, 1998 letter and cost estimate to the Responsible Party, four drums of purged groundwater were pumped by vacuum truck in June and transported to Silver Springs,Nevada for disposal at Petroleum Recovery of Nevada Monitoring took place on June 10 and July 6 Water depths and dissolved oxygen concentrations in the groundwater were measured on both days, and groundwater samples were collected on July 6 Water was present in all wells, and gradient maps were prepared for both days The natural gradient is to the northeast, but asphalt pavement in Yosemite Street to the west of the site appears to alter the gradient along the property boundary by limiting downard infiltration of surface water and lowering the water table beneath the street This forms a groundwater trough(low spot) along the property line There has been a drop in the water table of approximately 2 feet since monitoring began in April Dissolved oxygen concentrations were generally higher than they were during the previous two monitoring events in April and May Concentrations did not decline during purging, and several wells had consistent concentrations between l and 2 mg/l No statistically significant differences were apparent between wells with respect to distance from an 4RC infection boring All ten water samples were analyzed for TPH-gasoline, BTEX, and gasoline oxygenates, as directed by EHD and approved by the UST Fund No oxygenates were detected, and gasoline and BTEX concentrations were lower in all but one well in comparison to samples collected during the first quarter of 1998 TPH-g concentrations ranged from less than 50 ppb to 59,700 ppb, and benzene concentrations ranged from less than 0 5 ppb to 186 ppb 1