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29 January 2002 ' AGE-NC Project No. 98-0466 Page 22 of 25 concentrations of 4.3 mg/kg and 6.8 mg/kg,respectively. TPH-d,TPH-mo and formaldehyde were not detected in the grab ground water samples collected fi om each boring. • Dissolved chromium was detected in the ground water samples collected from boring PBS and PB6 at concentrations of 0.038 mg/l and 0.073 mg/l, resp ctively. The concentration detected in the PB6 water sample was slightly above the DHS M Contaminant Level ' (MCL) of 0.05 mg/l. Metals concentrations detected in the soil amples collected from PB5 and PB6 are at or near background concentrations. Elevated bromium in soil had been previously detected in soil sample DS 1-2 in the south end of tie drainage ditch; however ' other soil samples in the ditch and adjacent to the ditch h ive had only background concentrations, indicating one release point of limited extent. The DS1-2 sample also contained elevated concentrations of leand and zinc, neither of which were detected in the PB5 and PB6 grab ground water samples. AGE interprets the data to show a release of chromium, lead and zinc and TPH-d and TPH-mo to the western ditch that is of limited. vertical and lateral extent. The lead and zinc impacted shallows it in the ditch (DS 1-2) but ' has not inpacted ground water. Chromium, also impacting shallc w soil in the ditch(DS 1-2) has impacted groundwater in the downstream direction at concentrations slightly above and below the MCL. The mass of chromium apppears to be low. AGE believes the TPH-d, TPH-mo, formaldehyde, lead, zinc and chromium detected in the western ditch area to be of limited mass and extent and not likely to significantly impact ground water outside the immediate area. Further investigation of the area does not seem warranted. No other analytes of concern were detected in the soil and ground water samples collected from the west ditch area- Based reaBased on the data collected from the former Millwork Building wash-down area,AGE finds: • TPH-d and TPH-mo were detected in the ground water sample collected from boring PB8 at concentrations of 89 µg/1 and 330 µg/1, respectively. No other analytes of concern were ' detected in the ground water sample collected from boring P 8. Formaldehyde was not detected in the sample. The lack of detectible formaldehyde in the grab ground water suggests that the former use of the area as a wash-down area has not adversely affected ' ground water and is of little concern. However, detection of TP -d and TPH-mo in ground water at 56 feet to 60 feet bsg was not expected and cannot be explained with the data at ' hand, no former potential source for the contaminants are known in the immediate area. Further investigation may be warranted. ' Based on the data collected from beneath the 44 x 120 Storage Building sump, AGE finds: • Formaldehyde was detected in the groundwater sample collected from soil boring PB 10 at a concentration of 110 µg/1. The detected concentration is slight y above the DHS Drinking Ado=ced GeoBnAronmental,Inc.