|
GoApproximate Depth to Groundwater
<br />A -Zone Groundwater Gradient
<br />B -Zone Groundwater Gradient
<br />DISCUSSION:
<br />Groundwater in the A -Zone and B -Zane is measured at 55 to
<br />56 feet below ground surface (bgs)
<br />Groundwater in the A -zone flows radially toward Extraction
<br />Well (EX) -3 in the vicinity of the site Groundwater south of
<br />the site flows to the south under a hydraulic gradient of 0 0022
<br />feet/foot
<br />Groundwater in the B -zone flows to the southeast, a hydraulic
<br />gradient of 0 021 feet/foot, in the vicinity of the site Toward
<br />the south and east of the site, the groundwater flow direction
<br />bends to the south and hydraulic gradient decreases to
<br />approximately of 0 002 feet/foot
<br />Between March 21 and 23, 2001, SECOR conducted I" Quarter 2001 groundwater monitoring and sampling, in
<br />accordance with Cleanup and Abatement Order (CAO) No 5-00-704 Groundwater monitoring and sampling was
<br />performed for 30 wells Site wellswere gauged on the March 21, and 22, 2001 (Table 1) Wells were sampled
<br />from March 21 through 23, 2001, and sample results are presented on Table 2) Potentiometnc maps for A and B -
<br />Zone wells are presented as Figures 2 through 5 Concentration contour maps for select chemicals are presented as
<br />Figures 6 through 9
<br />iConcentrations of total petroleum hydrocarbons as gasoline (TPHg), benzene, toluene, ethylbenzene, and xylenes
<br />(BTEX compounds), methyl tertiary butyl ether (MtBE), tertiary butyl alcohol (TBA), dnsopropyl ether (DIPE),
<br />ethyl tertiary butyl ether (EtBE), tertiary amyl methyl ether (TAME), 1,2-dichloroethane (1,2 -DCA), and ethylene
<br />dibronude (EDB) were not detected m A -Zone wells MW -2, MW -12A, MW -13, and MW -20A TPHg was
<br />reported in two A -zone wells with concentrations of 980 ug/1 (MW -3) and 84 ug/l (MW -4) Benzene was reported
<br />in three wells with concentrations ranging from 0 52 ug/l (MW -11A) to 380 ug/1 (MW -3) MtBE was reported m
<br />twelve A -Zone wells with concentration ranging from 0 63 ug/1 (MW -8A) to 2,000 ug/l (EX -3) TBA was reported
<br />m well MW4 and EX -3 at concentrations of 13 ug/1 and 11 ug/l, respectively EtBE was reported m eight A -Zone
<br />wells with concentrations rangmg from 0 52 ug/1 (MW -6) to 38 ug/1(MW-4) TAME was reported in site wells
<br />MW -4, MW -9A, MW-14/EX-2, and EX -3 at concentrations rangmg from 0 70 ug/1(MW-14/EX-2) to 20 ug/l (EX -
<br />3)
<br />Concentrations of TPHg, BTEX compounds, MtBE, TBA, DIPE, ELBE, TAME, 1,2 -DCA, EDB, and methanol
<br />were not detected m B -Zone wells MW -7B, MW -11B, MW -12B, MW -17B, MW -18B, and MW -20B Benzene,
<br />toluene, and xylenes were reported in well MW -5B with concentrations of 0 59 ug/l, 13 ug/l, and 18 ug/l,
<br />respectively MtBE was reported in four B -Zone wells with concentrations ranging from 0 69 ug/1 (MW -8B) to 7 2
<br />ug/l (MW -10B) Ethanol was reported in four B -Zone wells with concentrations rangmg form 5 0 ug/1(MW-18B)
<br />to 25,000 ug/1 (MW -9B) EtBE was reported in B -Zone well MW -10B with a concentration of 2 1 ug/l
<br />Concentrations of TPHg, BTEX compounds, MtBE, TBA, DIPE, EtBE, TAME, 1,2 -DCA, EDB, and methanol
<br />were not detected in C -Zone wells MW -10C and MW -19C MtBE was reported m MW -10C and MW -19C with
<br />concentrations of 7 5 ug/l and 0 99 ug/l, respectively Ethanol was reported in both MW -10C and MW -19C with
<br />concentrations of 100 ug/1 and 4,400 ug/l, respectively
<br />
|