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20 March 2015
<br /> AGE Project No. 00-0769
<br /> ' Page 8 of 19
<br /> ' were detected in groundwater samples collected from the same wells at
<br /> maximum concentrations of 44,000 pg/I benzene, 59,000 pg/I toluene, 4,600 pg/I
<br /> ethylbenzene, and 37,000 pg/I total xylenes (MW-1).
<br /> ' 0 1,2-dichloroethane (1,2-DCA) was detected in groundwater samples collected
<br /> from wells MW-1, MW-213, MW-4A, and MW-5A at a maximum concentration of
<br /> ' 720 pg/I (MW-1).
<br /> • Tertiary-amyl methyl ether (TAME) was detected in groundwater samples
<br /> collected from wells MW-1 and MW-4A at a maximum concentration of 82 pg/l
<br /> ' (MW-1).
<br /> • No additional analytes were detected above laboratory detection limits in the
<br /> ' groundwater samples analyzed.
<br /> HU1: 60 feet to 70 feet bsq
<br /> ' • The depth to groundwater in well MW-10 was 20.86 feet btoc and the
<br /> groundwater elevation was 8.58 feet below NAVD88. Groundwater flow direction
<br /> ' could not be determined; MW-10 is the only well screened within this unit.
<br /> • TPH-g, BTEX, 1,2-DCA, and TAME were detected in the groundwater samples
<br /> ' collected from well MW-10 at concentrations of 63,000 pg/I TPH-g, 12,000 pg/I
<br /> benzene, 6,700 pg/I toluene, 2,900 pg/I ethylbenzene, 11,100 pg/l total xylenes,
<br /> 220 pg/l 1,2-DCA, and 62 pg/I TAME.
<br /> ' • No additional analytes were detected above laboratory detection limits in the
<br /> groundwater samples analyzed.
<br /> ' HU-2: 112 feet to 125 feet bsq
<br /> • Depths to groundwater were measured from HU-2 wells MW-2A, MW-3A,
<br /> ' MW-413, MW-513, MW-613, MW-7B, MW-813, and MW-9B and groundwater
<br /> samples were collected from HU-2 wells MW-2A, MW-3A, MW-413, MW-513, MW-
<br /> 613, and MW-7B.
<br /> ' • Depths to groundwater ranged between 20.25 feet (MW-8B) btoc and 22.60 feet
<br /> (MW-5B) btoc (Table 1). Groundwater elevations ranged between 10.88 feet
<br /> ' (MW-8B) below NAVD88 and 11.74 feet (MW-5B) below NAVD88.
<br /> • Utilizing site wells MW-2A, MW-4B, and well MW-813, groundwater was
<br /> calculated to be flowing toward the south-southwest under an average hydraulic
<br /> ' gradient of approximately 0.002 ft/ft. Figure 4 illustrates contoured groundwater
<br /> elevations as measured on 04 August 2014.
<br /> ' • TPH-g were detected in groundwater samples collected from wells MW-2A,
<br /> MW-3A, MW-413, MW-513, MW-6B, and MW-7B at concentrations ranging from
<br /> 1,500 pg/l in MW-2A to 21,000 pg/I in MW-3A. BTEX compounds were detected
<br /> Advanced GeoEnvironmental Inc.
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