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- � F -3 1 �. ft October 23, 1991 Quik Stop Market No. 120 Page 2 Project No. 3-49120-31 borings, collecting soil samples at 5-foot depth intervals for identification and anaiysi-, converting the borings to groundwater monitoring wells and collecting groundwatc' samples for laboratory analysis. During the course of this investigation it was tours. that product lines were leaking and petroleum hydrocarbons had affected tite soil "Ild til the site. The product lines were repaired, contaminated soil groundwater benea excavated and removed, and ttte excavation backfilled with clean fill. These activities inn report dated and findings were detailed in our Sail a (nd roundwater ltiv 5 i ''t October 9, 1990. 1n December 1990, a quarterly groundwater monitoring program was initiated. In April 1991, due t, regulatory concerns about hydrocarbons found in groundwater during the December sampling and analysis, an additional sampling and analysis was performed, The purposc of this was to confirm the non-detectable results of the March 1991 sampling and analysis. Field Operations RESNA measur,-d titre depth to groundwater and checked for the presence of floating product at each well using an optical interface probe. No measurable floating product was detected in any of the wells. The groundwater in each well was checked for the presence of surface sheen with a clear acrylic baiter: none was observed. Groundwater samples were then collected from each well following the procedures four outline li ed in our groundwater sampling protocol (Appendix A). App Y ng volumes of groundwater were removed from each well before sampling. Groundwater removed from the wells and equipment rinse water were placed in Department of Transportation-approved drums and left on-site pending the laboratory analytical results. Groundwater Elevations Depth to groundwater measurements were obtained prior to sampling and ranged from 46.09 to 47.04 feet below the surface and are included with the well elevations in Table 1. Groundwater elevations calculated from these measurements ranged from 34.81 to 35.02 feet b�mean sea level (MSL) based on available survey data. A groundwater elevation contour map generated from these elevations is included groundwater as lFigure stirface . he groundwater contour map shows a gently inclined predominantly easterly now at a gradient of approximately 0.0026. Laboratory Analyses The groundwater samples were transported to Applied Analytical (a state-certified laboratory) located in Fremont, California and analyzed for TPHD, TP G, ansamplingsB compon .t Table is The lof aboratory analyal tical reportslts from uarent and past attach d in AppendiB. is presented