ARCHIVED REPORTS_XR0006084 - Laserfiche WebLink

Home Browse Search

li _ F l 07 May 2004 h AGE-NC Project No 98-0534 IPage 11 of 14 measurements or changes of recharge/discharge of the local ground water could greatly modify the Iinferred ground water flow direction Ground water elevation data are summarized on Table 1 Dux the nine quarterly groundwater monito g events,low TPH-d concentrations were detected- �• in lfr samples at concentrations as high as `'µg/l, TPH g concentrations were detected in samples at concentrations as high as 800 µg/1 MTBE and/or various BTEX compounds were detected in 29 samples at concentrations as high as 350 µg/1 MTBE,0 62 µg/1 Benzene and 1 5 µg/1 Toluene Analytical results of ground water samples are summarized on Tables 2 4.0. WATER WELL RECEPTOR SURVEY r F I 03 March 2003 a representative of AGE performed a reconnaissance of visually observable potential receptors within a 2,000-foot radius of the above referenced site Water wells or other observable potential receptors were located during the reconnaissance Results of the March 2003 investigation are presented in Appendix C lie 5 0. ASSESSMENT OF HYDROCARBON-IMPACTED SOIL AND GROUND WATER 1 Between December 1998 and February 2004, 10 soil borings (P-1 through P-10) and eight ground fwater monitoring wells (MW-1 through MW-8) were installed at the site, nine ground water monitonng/sampling events were performed at the site to investigate the extent of hydrocarbon- impacted ground water in the vicinity of the former USTs - r 1 The greatest concentrations ofpetroleum hydrocarbon-impacted soil were encountered in soil boring ' P-9 at a depth of 15 feet bsg and in soil boring P-3 at a depth of 10 feet bsg(Table 3),P-1 is located near the southwest corner of the former UST pit and P-3 is located between former UST 1 and UST 4 (Figure 2) ' High concentrations of TPH-g and TPH-d-impacted ground water were encountered during advancement of probe borings P 1 through P 10 TPH-g, as detected in grab ground water samples - -� at a maximum concentration of 11,000 µg/1 in sample PT-H20,TPH-d was detected in grab ground 1 water samples at a maximum concentration of 7,000 µg/l in sample -H2O TBE and BTEX at maximum concentrations of 1' 600 1 1, 1, 230µ land compounds were detected µ� ,�rp� µ� ' 1,100 µg/l,respectively TBA and ETBE were detected at maximum concentrations of 42 µg/1 and 180 µg/l, respectively These initial high grab ground water concentrations were not detected in subsequent ground water monitoring events - 1 Since commencement of ground water monitoring the, following trends can be observed from the analytical data TPH-g has decreased from a maximum concentration of 800 µg/1 in MW-7 to non ' Advanced GeoEnvironmental,Inc 1 L ~ ' f