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T � 07 May 2002 AGE-NC Project No. 98-0466 Page 4 of 16 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 ditc that is of limited vertical and lateral extent. The lead and zinc impacted shallow soil in the ditch(DS 1-2) but has not inpacted ground water. Chromium, also impacting shallow soil in the ditch (DS 1-2) has impacted ground water 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, for dehyde, lead, zinc and chromium detected in the western ditch area to be of limited mass an I extent and not likely to significantly impact ground water outside the immediate area. No other analytes of concern were detected in the soil and ground water amples collected from the west ditch area. AGE proposes advancing two soil borings in the down-stream directi n of the western ditch to collect soil and ground water samples for metals analysis. 3.2. MILLWORKS WASH-DOWN AREA Formaldehyde was detected in two surface soil samples collected and an yzed by Kleinfelder in this area at concentrations of 36 mg/kg and 45 mg/kg. Phenols were detected in one sample at a concentration of 0.92 mg/kg. Kleinfelder (1992), summarizing the findfiigs, did not consider these concentrations to be high enough to warrant additional investigation. A opy of the original report of findings was not available to AGE. During the November 2001 site investigaiton, one boring (PB8) was advanced to collect a grab ground water sample for formaldehyde,phenol,VOCs and TPH-d,-mo d-g analyses. TPH-d and TPH-mo were detected in the ground water sample at concentrations of 89 micrograms per liter (µg/1) and 330 gg/l, respectively. No other analytes of concern were de ected in the ground water sample collected from boring PB8. Formaldehyde was not detected ii the sample. The lack of detectible formaldehyde in the grab ground water suggests that the form use of the area as a wash- down area has not adversely affected ground water and is of little conc . However, detection of TPH-d and TPH-mo in ground water at 56 feet to 60 feet bsg was notexpected;no former potential source for the contaminants are known in the immediate area. AGE proposes to advance two borings in the area to assess ground watt r for TPH-d and TPH-mo. 3.3. NORTH STORM WATER RETENTION BASIN The north storm basin receives surface runoff from the northern half o the site and possibly may have received traces ofwastes. Kleinfelder(1992)summarized analysis o two surface water samples Advanced CeoEnvironmenta4 Inc.