Laserfiche WebLink
v <br /> 1 <br /> ASSOCIATESATC <br /> I NC <br /> collected in March 2000, the most recent sampling event, contained no concentrations of BTEX, <br /> TPHg or fuel oxygenate additives above laboratory method detection limits <br />' No petroleum constituents have been detected water samples collected from the on-site domestic <br /> well <br /> 1 Analytical results ofoundwater les are summarized In Table 2 <br /> �' samples <br />' 3.2.1 Mass Balance Calculations-Groundwater <br /> Using groundwater analytical results presented in Table 2, the most recent data available, ATC <br /> estimated the lateral extent of dissolved TPHg, and benzene concentrations beneath the site <br /> performed mass balance calculations to estimate the mass of residual contamination in the site's <br /> saturated zone Mstoncally, only Petroleum hydrocarbons were detected in the immediate <br /> vicinity of the former USTs in groundwater grab samples from bonngs SBI and SB2 ATC <br /> conservatively utilized these analytical results it the groundwater mass balance calculations <br /> 1 The total mass of dissolved TPHg present in the saturated zone is estimated to be less than <br /> kilogram and less than one pound The total mass of benzene present In the groundwater is <br /> estimated to be less than one one-thousandth of a kilogram and less than one one-thousandth of a <br /> pound Mass balance calculations are included in Appendix B <br /> 4.0 WELL SURVEY <br /> In October 1999, ATC performed a well survey for the site at the request of PHS/EHD in their <br /> 1 correspondence dated October 9, 1998 ATC reviewed Department of Water Resources (DWR) <br /> groundwater well construction logs, San Joaquin County well installation permits, and conducted <br /> a site walk in the vicinity of the site to identify any groundwater wells located within a 2,000-foot <br /> 1 radius of the site The well survey is summarized in ATC's Summary Report of Supplemental <br /> Subsurface Investigation dated October 15, 1999 Pertinent well survey information In included <br /> 1 in Appendix C <br /> The records search revealed fifteen wells within approximately 2,000 feet of the site A site <br /> 1 reconnaissance was performed on June 25, 1999 and an additional eighteen wells were located <br /> within approximately 2,000 feet of the site The wells were located on the map according to "well <br /> location" description information provided on the well construction logs and well installation <br /> 1 permits <br /> There is one well located on site Five groundwater wells are located on adjacent properties <br /> 1 Based on on-site water measurements, the underlying groundwater gradient direction is to the <br /> southeast The San Joaquin County Flood Control and Water Conservation District's Spring <br /> 1997 Groundwater Report indicates the inferred regional groundwater gradient is to the <br /> northeast Based on the distance from the site and the site's groundwater analytical data, it is <br /> w\14885Vq)orls\NFA-Request doe 5 <br />