ARCHIVED REPORTS_XR0006947 - Laserfiche WebLink

Home Browse Search

I r ' , 1 1 ' 15 October 2002 ` i AGE-NC Project No 97-0333 ' Page 6 of 8 , t ' collected from wells MW-1,MW-2,MW-3,MW-4 and MW-6 at concentrations as high as 190,000 µg/l (MW-2) ' 1 , ' BTEX constituents were detected at wells MW-2, MW-4 and MW-6 at concentrations as high as 9,200 µg11 toluene(MW-2) The greatest benzene concentrations were detected from well MW-6 at a concentration of 4,900 µg/l MTBE was detected by EPA Method 8020 in the water samples from MW-1 through MW-4 and MW-6 at concentrations as high as 410,000µg/1(MW-6),MTBE was detected from MW-1 through ' f MW-4 and MW-6 utilizing EPA Method 8260 Modified at concentrations as high as 270,000 µg11 1 (MW-6) ' Utilizing EPA Method 8260 Modified, TAME was detected in samples collected from MW-1, MW-2, MW-3 and MW-6 at concentrations as high as 2,800 g1g/l, TBA was detected from MW-1 at a concentration of 100 µg/1 No other fuel related constituents were detected above the respected laboratoryreporting limits ' Previous and current analytical results of ground water,monitoring well samples are summarized in I Tables 6 and 7 The laboratory reports(Castle Analytical Laboratory Reference No 4727)and cham- I of-custody forms are presented in Appendix E' , I I 4.0. SUMMARY AND CONCLUSIONS r1 !! The irliplic`ations from the May 2002 ground water monitoring event are as follows ' • Ground water flow direction at the site was inferred to`be radially Inward towards wells MW-2; MW-6 land EW-1 at an approximate (gradient of 0 004 ft/ft or less (Figure 3), however,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 ' ! '� � � ,• The ground water elevation atthe site was within the screened intervals of wells MW-1 ' I through MW-6, which should" ,yield samples 'fully representative of shallow ground water conditions I 1 I • Ground water'elevation decreased at the site an average 128 feet between the March 2002 and the June 2002 ground water monitoring events, the decrease of ground water elevation 4i is probably due;to seasonal fluctuation E j I � I Current and previous analytical results) indicate that the core of the dissolved petroleum,' I . I hydrocarbon plume appears to be located in the area of MW-2(screened between 12 and 32 Advanced CeoEnvironmental,Inc , I , rj I