ARCHIVED REPORTS_XR0007193 - Laserfiche WebLink

Home Browse Search

I 04 y . April AGE-NC Protect No 98-0505 Page 3 of 5 ' 3.0. FINDINGS Groundwater elevations and flow directions were inferred from field data Hydrocarbon-impact to Iground water was characterized from laboratory analytical data ' 3 1 GROUND WATER ELEVATION AND GRADIENT The average ground water elevation of the seven shallow ground water monitoring wells on 01 ' March 2001 was approximately 11 42 feet below mean sea level (msl), with the average depth of water at 19 1 feet below casing tops The ground water table occurred withm the screened intervals ofwells MW-7 and MW-8 During the March monitoring event,groundwater was between 9 68 and ' 10 94 feet above the screened intervals in monitoring wells MW-1 through MW-5 Therefore, the five ground water monitoring wells were "drowned", and may not have yielded samples fully representative of groundwater conditions near the top ofthe saturated zone where fuel hydrocarbons ' would be expected to have the greatest impact The ground water table occurred approximately 41 feet above the screened Interval of the deep well MW-6 '• Based on data collected during the March 2001 ground water monitoring event, the gradient was calculated to be 0 01 ft/ft (Figure 3) near the former UST area Ground water flow direction was generally toward the southeast I 3 2 ANALYTICAL RESULTS FROM GROUND WATER SAMPLES ' Monitoringwells MW-1 through MW-8 were sampled on 01 March 2001 The analytical results of g P the ground water samples were as follows ' • TPH-g was detected in ground waters samples collected from each monitoring wells sampled at the site (MW-1 through MW-8) TPH-g concentrations ranged from 51 micrograms per ' liter (µg/1) In MW-5 to 97,000 gg/l in MW-1 Benzene was detected in the ground water samples collected from monitoring wells MW-1 through MW-7 at concentrations ranging ' from 0 71 gg/l (MW-5) to 7,900 µg/l (MW-1) Toluene was detected in monitoring wells MW-1 through MW-6 at concentrations ranging from2 9 gg/1(MW-4)to 20,000 µgd(MW- 1) Ethylbenzene was detected in samples collected from MW-1 through MW-6 at ' concentrations ranging from 0 75 µg/1 (MW-5) to 2,400 µg11 (MW-1) Total xylenes were detected in samples collected from monitoring wells MW-1 through MW-7 at concentrations ranging from 1 6 µgm (MW-7) to 11,000 gg/1 (MW 1) ' • MTBE and other fuel oxygenates were not detected in the ground water samples collected from the site ' Advanced GeoEnvironmental,Inc