ARCHIVED REPORTS_XR0012635 - Laserfiche WebLink

Home Browse Search

Quik Stop Market No. 120 January 17. 1991 Project No. 3-49120-31 Page 2 alarm mode. The scope of the work included drilling three exploratory borings,collecting soil samples at 5-foot depth intervals for identification and analysis,converting the borings to groundwater monitoring wells and collecting groundwater samples for laboratory analysis. During the course of this investigation it was found that product lines were leaking and petroleum hydrocarbons had impacted the soil and groundwater beneath the site. The product lines were repaired, contaminated soil excavated and removed, and the excavation backfilled with clean fill. These activities and findings were detailed in our Soil and Groundwater Investigation report dated October 9, 1990. Field Operations Exceltech measured the depth to groundwater and checked for the present;, 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 bailer: none was observed. Groundwater samples were then collected from each well following the procedures outlined in our groundwater sampling protocol(Appendix A). Approximately four well-casing 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 t^ sampling and ranged from 45.03 to 46.00 feet below the surface and are included with the well elevations in Table 1. Groundwater elevations calculated from these measurements ranged from 33.75 to 33.98 feet below mean sea level(MSL)based on available survey data. A groundwater elevation contour map generated from these elevations is included as Figure 3. The groundwater W. contour map shows a gently inclined groundwater surface with a predominantly easterly flow at a gradient of approximately 0.0025 foot per foot(horizontal to vertical). �. Laboratory Analyses The groundwater samples were transported to Anametrix,Inc.(a state-certified laboratory) located in San.lose, California and analyzed for TPIHD,TPHG, and BTEX. A summary of the analytical results from current and past well samplings is presented in Table 1. The laboratory analytical reports are attached in Appendix B. Laboratory analyses revealed hydrocarbon constituents in the groundwater from monitoring wells MW-2 and MW-3. The results of the analyses were reported as follows: