ARCHIVED REPORTS XR0004631 - Laserfiche WebLink

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v o A S 5 0 C I A T E S I N C constituents were detected in the soil samples collected dunng installation of wells MW 1 and MW3 On-site soil borings SBI through SB6 were advanced to depths of approximately 26 to 31 feet bgs Off-site soil bonngs SB7 through SB12 were advanced to depths of approximately 21 to 30 feet bgs Trace amounts of TPHg and BTEX constituents were detected in the soil samples collected from soil borings SB1 through SB5 TPHg and BTEX constituents were not detected in the soil samples collected from soil borings SB5 through SB12 Criterion 3: No waters of the State, or other sensitive receptors are likely to be impacted. A sensitive receptor survey for the site was performed by ATC in 2001 The City of Ripon's public supply well #4, located approximately 300 feet to the north, is the closest well to the site The well is screened in a lower aquifer and is approximately 257 feet ' deep According to the EHD, the well is not currently being used since the lower aquifer was contaminated by another site Approximately 1,800 feet east of the site at 334 East Main Street, the logs indicated four monitoring wells are present at a gasoline service station (labeled Well No 1 on the map) These wells are located hydraulically cross gradient from the site and are used for monitoring purposes only Approximately 1,800 feet south of the site near Fourth Street and Elm Street is a municipal well identified as Well 6 (labeled Well No 3 on the map) The well is 340 feet deep, 16 inches in diameter, and screened from 84 feet to 338 feet below ground surface A sanitary seal is present from the surface to 54 feet bgs The well is hydraulically upgradient from the site Three other wells were identified within 2,000-foot radius during the survey Each well has been properly abandoned The nearest surface water body, the Stanislaus River is located approximately 5,000 feet to the south, in an assumed upgradient direction For the investigation, groundwater wells ' were installed only in the shallowest aquifer Laboratory analytical data from the most recent groundwater sampling, conducted in June 2004, indicated that there were low concentrations of TPHg and BTEX constituents detected in samples collected from wells ' MW1 through MW3 Therefore, the likelihood of pollutants remaining in the aquifer threatening these potential receptors is expected to be low 6.2 Appendix A Check List Appendix A of the Tri-Regional Board's recommendations checklist of required data for site closure of USTs has been reviewed The checklist is included in this report as Appendix A w 114981\rep"r closure doe 8