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�. 12 March 1999 AGE-NC Project No. 95-0128 Page 3 of 5 3.2. ANALYTICAL RESULTS FROM GROUND WATER SAMPLES MAI received, extracted and analyzed the ground water samples on 05 January 1999. MAI issued a report dated 12 January 1999. The analytical results from the ground water samples are as follows: a. • During the December 1998 ground water monitoring event, dissolved petroleum hydrocarbons were not detected in the ground water samples from the drowned wells MW I and MW3;trace concentrations of toluene and total xylenes were detected in the sample from the drowned well MW2. ,ra Dissolved petroleum hydrocarbons were detected in all the properly screened monitoring wells. The highest concentrations of hydrocarbons were detected in the water sample from the down-gradient monitoring well MW5, which contained 72,000 kzgll TPH-g, 9,800 gg/l .r TPH-d, 5,100 yg/1 benzene, 11,000 ,ug/1 toluene, 4,200 Mcg/1 ethylbenzene and 20,000 µg/l total xylenes. The Iowest concentrations of hydrocarbons were detected in the sample from the up-gradient monitoring well MW7,which contained 68 gg/I TPH-g, 110/.cg/I TPH-d, 5.7 i- deg/l benzene, 0.64 µg/l toluene, less than 0.5 Mcg/I ethylbenzene and 0.61 Mcg/l total xylenes. A lower concentration of benzene, 3.4 /..zg/l, was detected in the sample from MW6. • The concentrations of dissolved petroleum hydrocarbons decreased an order of magnitude in samples from MW6 and V W l, and increased an order of magnitude in samples from MW4 and MW5. TPH-d was detected in samples from all the properly-screened monitoring wells at concentrations as high as 9,800 pg/I (MW5), but was not detected in samples from the deeper-screen wells MW I, MW2 or MW3. a MTBE was detected in ground water samples collected from monitoring wells MW2 through MW7 and from vapor well V W I. Detected concentrations of MTBE ranged from 7.5 ,ug/l (MW2) to 950 µg/l (MW5). • TAME was detected at 1.1 ug/I in the sample collected from the up-gradient monitoring well i. MW7. • TBA, DiPE and ETBE were not detected in the ground water samples collected during the 31 December 1998 ground water monitoring event. Laboratory results of water samples analyzed for petroleum hydrocarbons are summarized in Tables 2 and 3. The laboratory reports for the quarterly monitoring event (MAI Laboratory ID No. 01297 to 0 13 04) QA/QC reports and chain-of-custody form are included in Appendix B. Advanced CcoEnlronmental Inc. r` Le