ARCHIVED REPORTS_XR0010598 - Laserfiche WebLink

Home Browse Search

29 March 2001 • AGE-NC Project No 97-0249 Page 4 of 6 ' MTBE was detected in ground water samples collected from wells MW-4 and MW-6 at concentrations as high as 91 ug/l TBA was detected in water samples collected from MW-1,MW-2 and MW-3 at concentrations as high as 81 µg/1 No other fuel oxygenated compounds were detected ' in any other ground water samples Laboratory analysis of the sample collected from domestic drinking water well DW-1 did not detect ' any constituents of concern above laboratory reporting limits, however the sample collected from domestic water well RDW-1 detected MTBE at a concentration of 8 3 µg/l Previous and current analytical results of ground water monitoring well samples are summarized in Tables 2 and 3, analytical results of the ground water samples collected from the domestic drinking water well DW-1 are summarized in Table 4 The laboratory reports (McCampbell Analytical Inc ' I D No 62517 through 62522) and chain-of-custody forms are presented in Appendix C ' 4 0 SUMMARY AND CONCLUSIONS • The implications from the March 2001 ground water monitoring event are as follows Ground water flow direction for the area bound b o y Three B's Truck Plaza wells MW-1 through MW-6 and Flag City Chevron wells MW-7, MW-12A and MW-13A was generally toward the east at a gradient of 0 003 fl/ft, or approximately 16 feet per mile and less (Figure 3), due to the low gradient at the site, slight variations In ground water measurements or ' changes of recharge/discharge of the local ground water could greatly modify ground water flow direction • Ground water flow direction at the site may have been influenced by pumping of the Rocky's Restaurant (14659 Thornton Road,Lodi CA) domestic drinking water well and/or by ground water extraction activities at Flag City Chevron(6421 Capitol Avenue) ' • The ground water elevation at the site was within the screened intervals of wells MW-1 through MW-6 and is representative of shallow ground water conditions ' • Ground water elevation at the site increased an average 198 feet from the December 2000 ground water monitoring event to the March 2001 ground water monitoring event • The lateral extent of the dissolved petroleum hydrocarbon plume is not known toward the ' south, southwest, west, northwest, north and northeast of the area bound by wells MW-1 through MW-6, the vertical extent on the site is not known • The elevated petroleum hydrocarbon concentrations detected in water samples collected from wells MW-1, MW-2, MW-3 (screened between 5 and 25 feet bsg) suggest that these wells may be screened within or near the "core area' of the dissolved petroleum hydrocarbon ' Advanced GcoEnvironmental,Inc 1 '