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13 September 2012
<br /> AGE-NC Project No.99-0682
<br /> Page 12 of 17
<br /> • TPH-d were detected in the samples collected from wells MW-1A, MW-7, MW-8
<br /> and MW-10 at concentrations between 1,600 pg/I (MW-7)and 30,000 pg/I (MW-8).
<br /> • BTEX compounds were detected in samples collected from MW-1 A, MW-7, MW-8
<br /> and MW-10 at maximum concentrations of 3,600 pg/l benzene, 12,000 pg/1 toluene,
<br /> 1,900 pg/I ethylbenzene and 10,600 pg/1 total xylenes (MW-8); xylenes were
<br /> detected in the samples collected from MW-6 at a concentration of 2.2 pg/I.
<br /> • TAME was detected in samples collected from wells MW-7, MW-8 and MW-10 at
<br /> a concentrations of 4.4 pg/l, 9.7 pg/I and 4.5 pg/I.
<br /> • 1,2-DCA was detected in the samples collected from well MW-8 at a concentration
<br /> of 5.2 pg/l.
<br /> • Various metals were detected in samples collected from wells MW-1A, MW-2,
<br /> MW-6, MW-7, MW-8, and MW-10; Fe and Al concentrations in well MW-8 remain
<br /> above baseline concentrations; and Fe concentrations in MW-1A remain below
<br /> baseline concentrations. CrVI was not detected above laboratory reporting limits in
<br /> the samples collected. However, Cr and Copper(Cu)were detected in the samples
<br /> collected from well MW-8 at concentrations of 0.013 pg/I and 0.038 pg/l,
<br /> respectively (Table 4). Cr was detected below the Primary MCL of 0.05 mg/l.
<br /> • Anions (bromate, bromide, chloride, nitrate, nitrate as nitrogen, nitrate as NO3-,
<br /> sulfate, ammonia, and TDS) were detected in the samples collected from wells
<br /> MW-1A, MW-2, MW-6, MW-7, MW-8 and MW-10, with the exception of ammonia
<br /> from wells MW-1A and MW-2. Concentrations of bromate, bromide, and ammonia
<br /> continue to be detected near or below baseline concentrations in wells MW-1A and
<br /> MW-8; and concentrations of bromate and bromide in wells MW-6 and MW-7
<br /> continue to be detected just above baseline concentrations (Table 5). Additionally,
<br /> concentrations of chloride and nitrates increased in samples collected from well
<br /> MW-8 and decreased in samples collected from well MW-1A.
<br /> 4.2.5. Post-ISCO Monitoring Event No. 2: Analytical Results
<br /> On 05 July 2012, post-ISCO groundwater samples were collected from wells MW-1 A, MW-
<br /> 6, MW-7, MW-8 and MW-10 to evaluate the effectiveness of the ISCO pilot test. The
<br /> following is a summary of the results:
<br /> • TPH-g were detected in the samples collected from wells MW-1A, MW-6, MW-7,
<br /> MW-8 and MW-10 at concentrations between 320 pg/I (MW-6) pg/I and
<br /> 100,000 pg/l (MW-8).
<br /> Advanced GeoEnvironmental,Inc.
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