ARCHIVED REPORTS_XR0005294 - Laserfiche WebLink

Home Browse Search

I detected in all five of the grab ground water samples analyzed, at concentrations from 430 µg/1 to 1,100 µg/1. TPH-g was detected in three soil samples analyzed at concentrations as great as 350 milligram per kilogram(mg/kg)in soil sample P10-20'. TPH-g was detected in soil from 15 feet and 25 feet bsg at concentrations of 160 mg/kg and 14 mg/kg, respectively. TPH-g was not detected in soil samples collected at a depth of 30 feet or 35 feet bsg. TPH-d was detected in soil samples collected from depths of 15, 20 and 25 feet bsg at concentrations of 5,100 mg/kg, 13,000 mg/kg and 490 mg/kg,respectively. TPH-d was not detected in soil collected at depths of 30 feet bsg or below. tOn 26 October 2001, a total of four soil probe borings (P 12A/B and P 13A/B)were advanced at the site to the south and near the former UST location. Probe borings were advanced in the area of the former USTs to collect depth-discrete water samples. TPH-d was detected in all four of the grab ground water samples at concentrations from 130 micrograms per liter(µg/1)to 550 µg11. On 2$ and 29 October 2002, monitoring well MW-5 and six ozone sparge wells (OPS 1 A through OPS3B)were installed. A total of three soil samples were collected from MW-5 and analyzed for ' TPH-g, TPH-d, BTEX and fuel additives.None of the target compounds were detected in the soil samples analyzed. ' Between June 1996 and February 2003, twenty ground water monitoring and sampling events were performed at the site to monitor dissolved petroleum hydrocarbon concentrations in ground ' . water and to characterize ground water flow direction and gradient at the site. • During the most recent sampling event, TPH-d was detected in ground water samples collected from wells MW-1 and MW-4 at concentrations of 20,000 µg/1 and 93,000 µg/1, respectively. TPH-g was detected in samples MW-1 and MW-4 at concentrations of 1,400 µg11 and 6,700 µg/l, respectively. The BTEX constituents ethylbenzene,toluene and total xylenes were detected in sample MW-4 at concentrations of 1.8 µg/1, 2.1 µg/1 and 8.4 µg11, respectively. • Ground elevations have increased approximately 0.8 feet during the monitoring period. • The lateral extent of the dissolved petroleum hydrocarbon plume is delineated by the current area bounded by wells MW-1 through MW-5 and soil borings. i GROUND WATER DEPTH AND FLOW DIRECTION In February 2003, ground water depth was measured at approximately 24 feet below surface grade (bsg). A review of historical AGE depth to ground water measurements indicates that ground water depth near the site has fluctuated between approximately 15 and 20 feet bsg. Ground water flow direction at the site can vary seasonally;however,the overall regional flow ' direction is west to southwest. Advanced GeoEnvironmental,Inc.