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20 December 2011 <br />AGE-NC Project No. 02-0926 <br />Page 2 of 3 <br />August 2011. <br />Total petroleum hydrocarbons quantified as gasoline (TPH-g) were reported in well <br />MW-5 at a concentration of 310,000 micrograms per liter (pg/I). <br />Benzene, toluene, ethylbenzene, and total xylenes (BTEX) compounds were <br />reported in well MW-5 at concentrations of 43,000 pg/I, 50,000 pg/I, 4,800 pg/I, and <br />28,000 pg/I, respectively. <br />Fuel additives tertiary-amyl methyl ether (TAME) and 1,2-dibromoethane (EDB) <br />were reported in the sample collected from well MW-5 at concentrations of 140 pg/I <br />and 640 pg/I, respectively. <br />The fuel additive 1,2-dichloroethane (1,2-DCA) was reported in samples collected <br />from wells MW-3 and MW-5 and concentrations of 51 pg/I and 250 pg/I, <br />respectively. <br />Deep Monitoring Well MW-6 (screened 70 feet to 75 feet bsg) <br />Depth to ground water in well MW-6 was measured as 33.41 feet btoc and ground <br />water elevation was calculated as 14.88 feet below NAVD88 (Table 1). <br />No additional analytes were reported at or above laboratory detection limits in the ground <br />water samples analyzed. Analytical results of water samples collected in August 2011 are <br />summarized in Table 2. The estimated lateral distribution of dissolved concentrations is <br />depicted in Figure 4. The laboratory report (Cal Tech Environmental Laboratory Lab <br />Project. No. CT214-1104038), quality assurance/quality control report, and chain-of- <br />custody form are included in Appendix D. Depth to water and laboratory analytical data <br />were uploaded to the State GeoTracker database under confirmation numbers <br />3836542785 and 2994399964. <br />4.0. CONCLUSIONS <br />Based upon the results of the ground water monitoring, AGE presents the following <br />conclusions: <br />Shallow zone dissolved TPH-g, BTEX, 1,2-DCA, EDB and TAME are undefined to <br />the west of well MW-5, to the east of boring B-6. The dissolved ground water plume <br />appears to be defined in all other directions. <br />The core of the plume appears to be centered around the former underground <br />storage tank area, surrounding well MW-5 and generally radiates towards MW-3 <br />south of the UST area. Hydrocarbon concentrations decreased slightly in well MW-5 <br />Advanced GeoEnvironmental, Inc.