Laserfiche WebLink
I23 September 2002 <br /> AGE-NC Project No 95-0128 <br /> Page 4 of 7 <br /> • Five metals (Cd, Cr, Cu, Pb,Ni and Zn) in accordance with EPA Method 200 Modified and <br /> • pH in accordance with EPA Method 150 1 <br /> 4.0. FINDINGS <br /> Ground water elevations were determined by subtracting the measured depths-to-water from the <br /> surveyed casing elevations Ground water flow directions were determined by contouring the water <br /> elevations on a scaled site plan Contaminate impact to ground water samples was assessed by <br /> laboratory analysis The mass of hydrocarbons removed by ground-water extraction was calculated <br /> from the volume of water treated and the concentrations of contaminants from laboratory analysis <br /> I ' <br /> 4 1 GROUND WATER ELEVATION AND GRADIENT <br /> The ground water elevation on 14 May 2002 ranged from 18 52 to 19 82 feet below mean sea level <br /> (MSL), the average ground water elevation was approximately 0 18 feet higher than the average <br /> groundwater elevation during the February 2002 monitoring event The groundwater table occurred <br /> within the screened interval of the shallow-screened monitoring wells (Table 1), wells MW-1 to <br /> MW-3, MW-11B and MW-12B were deeper-screened wells and are currently drowned The depth <br /> to ground water and ground water elevation data is summarized in Table 1 <br /> I The areal ground water flow direction was inferred to be northeast at gradients of between 0 004 ft/ft <br /> to 0 007 ft/ft An approximately 90-foot diameter cone of depression was observed at the northeast <br /> corner of the site due to drawdown of the water table by extraction well EW-1 (Figure 3), ground <br /> Iwater gradients greater than 0 05 ft/ft were observed within this depression <br /> 4 2 ANALYTICAL RESULTS OF MONITORING WELL GROUND WATER SAMPLES <br /> TPH-g was detected in ground water samples MW-4, MW-5 and VW-1 at concentrations of <br /> 3,000 micrograms per liter(µg/1), 23,000 µg/l, and 16,000 µg/l, respectively, TPH-d was detected <br /> in the same samples at concentrations of 1,300 µg/l, 5,300 µg/1 and 270 µg/1, respectively <br /> BTEX compounds were detected in samples MW-4,MW-5 and VW-1, at maximum concentrations <br /> of 370 µg/1 benzene, 280 µg/1 toluene, 1,600 µg/1 ethylbenzene and 5,500µg/1 xylenes from sample <br /> MW-5 <br /> • <br /> Advanced GeoEnWon mental Inc <br /> I <br />