ARCHIVED REPORTS_XR0004605 - Laserfiche WebLink

Home Browse Search

WELL CONSTRUCTION REPORT AND QUARTERLY MONITORING REPORT FORMER DIAMOND LUMBER-MANTECA AUGUST, 1996 4.0 SUMMARY 4.1 Results of Groundwater Laboratory Analyses Analytical results for the development samples indicated TPH G in MW-7-P at 4,900 micrograms per liter (µg/1) and non-detect at the method detection limit in MW-8-P BTEX was non-detect at the method detection limit in MW-8-P and present in MW-7-P at 330, 15, 18, and 680 µg/l, respectively Analytical results are summarized in Table 2 and the laboratory reports and COC documents are included in Appendix E 4.2 Groundwater Conditions The depths to water in wells MW-7-P and MW-8-P prior to development sampling were 16 43 and 16 76-feet bgs, the corresponding elevations were 16 93 and 17 10-feet below mean sea level (MSL) Groundwater elevation data is summarized in Table 1 The depths to groundwater measured on June 12, 1996 ranged between 16 89 and 17 49-feet bgs The elevations of the groundwater ranged from 16 55 to 16 04-feet above MSL The direction of the groundwater flow was calculated using the BEI wells and SRK wells, separately This was done because the wells are perforated at slightly different depths and their respective water levels appear to reflect the hydrologic conditions in two somewhat different water bearing zones The groundwater directions of flow and gradients for the two well groups are an east northeasterly direction at a gradient of 0 013-feet/feet (ft/ft) for the BEI wells and northwesterly direction and gradient of 0 0059-ft/ft for the SRK wells The two well clusters continue to show differences in groundwater elevations when compared to each other ' When incorporating the new wells into the groundwater flow measurements,groundwater flow appears to be in a more northerly to north-northeasterly direction at gradients ranging from approximately 0 002 to 0 003-ft/ft Park will monitor this flow direction and gradient 4.3 Results of Soil Laboratory Analysis Of the six soil samples (MW7-10, MW7-15, MW7-20, MW8-10,MW8-15, and MW8-20) submitted for analysis, detectable levels of TPH G, toluene, ethylbenzene, and total xylenes were ' reported in sample MW7-20 at concentrations of 101, 0 6,10 and 5 9 milligrams per kilogram (mg/kg), respectively Benzene was non-detect in all samples tested Analytical results are summarized in Table 3 and the laboratory reports and COC documents are included in Appendix ' F - ' 5.0 CONCLUSIONS . The following conclusions have been reached after reviewing and analyzing the results of the soil and groundwater monitoring at the site 5