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1 INTRODUCTION i Former Exxon Retail Site (RS) 7-3708 is an active U S A Petroleum station Iocated at 2705 Country Club Boulevard in Stockton, California, at the northwest corner of the intersection of Ryde Avenue and Country Club Boulevard Elevation of the ground surface at the site is approximately 1 to 2 feet above mean sea level The site slopes down toward the northeast and southwest corners From a slight topographic, high across the center I There are two underground storage tanks at the site containing diesel fuel and unleaded gasoline Groundwater monitoring has been conducted at the site since 1991 2 GROUNDWATER MONITORING On 26 February 2001, wells MW1, MW4-MW10, VEW1, and VEW3 were gauged Groundwater samples were collected from these wells and the samples were analyzed for Total Petroleum Hydrocarbons as gasoline (TPH-g), for benzene, toluene, ethylbenzene, and total xylenes (BTEX), and for methyl t-butyl ether (MTBE) IThe current depth-to-water measurements and calculated groundwater elevations are presented in boldface type in Table 1, along with previous data Current groundwater elevations are also shown Iin Figure i The groundwater flow direction on 26 February was to the south-southeast, with a gradient of approximately 0 003 Liquid-phase hydrocarbons were not observed in any of the wells After the depths to watc,r were measured the wells were purged Field parameters of pH, temperature, and electrical conductance of the purged water were measured for approximately every well casing volume removed during purging Copies of the field documents are included as ' Appendix A When the field parameters were, stable (less than a 10 percent change from the previous reading for temperature and electncal conductance and not more than 0 1 pH units) and ' approximately 3 casing volumes were removed from each well, purging was stopped and samples were collected using factory-cleaned disposable bailers The samples were poured into 40-m1 glass VOA vials and stored in an ice-filled cooler All samples were handled and transported under chain ' of custody The samples were submitted to SPL, Inc in Houston, Texas, and were analyzed for TPH-g by Cal ' EPA-modified EPA Method 8015 and for BTEX and MTBE by EPA Method 802113 The samples in which MTBE was detected, were also analyzed for MTBE by EPA Method 8260B for confirmation The results are presented in boldface type, along with previous analytical data, in ' Table 1, and are shown in Figure 1 The laboratory analytical report and chain-of-custody documentation are included in Appendix B ' 3 WORK PROPOSED FOR NEXT QUARTER Groundwater will be gauged and sampled in May 2001 Groundwater samples will be analyzed for ' TPH-g, BTEX, and MTBE Based on the proximity of the site to residential properties, ETIC Engineering will perforin a well survey to determine if there are any domestic wells in the immediate area This survey will include a door-to-door canvassing to interview residents I f eocts7;'08 hlavi 14 A 0.0 I I S clue 1