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A S S D C I A T E S I N C r.: TPHd was reported at levels ranging from non-detected (less than 1.0 ppm)to 720 ppm in soil samples collected across the site. No TPHd was detected in borings SB-7 or MW-5. Results of laboratory Eanalyses of soil samples are summarized in Table 1. G Soil samples collected from depths greater than 11 feet below grade were within the saturated zone. Analytical results of those samples are more indicative of groundwater contamination rather than soil contamination. Results of soil samples collected in the vadose zone (less than 11 feet deep) suggest that shallow soil contamination is somewhat random and not laterally continuous across the site. Y Furthermore, no BTEX constituents are present at significant levels. ` In September 1999, ATC supervised the advancement of soil borings SB-11, SB-12, and SB-13 at locations approximately 15 feet northwest, south, and northeast of well MW-4, respectively. Analytical data indicated the groundwater sample from soil boring SB-12 was impacted with TPHd at a concentration of 24,000 ppb. the groundwater samples from SB-11 and SB-13 contained very low to nondetectable concentrations of TPHd. Results of laboratory analysis performed on selected soil k-={ samples indicate that TPHd was present in only the samples collected between 14 and 16.5 feet bgs. Field observations indicated that the samples at these depths also exhibited the highest FID ifr``r`'J measurements. Soil samples SB11-15.5, SB12-16.5, and SB13-14.0 contained detectable concentrations of TPHd at 390 ppm, 290 ppm, and 1,100 ppm, respectively. All the remaining soil F' samples were not detected. The September 1999 subsurface investigation activities are detailed in r ATC's Summary Report, Suhsurface Investigation, dated January 10, 2000. } A groundwater pumping test was conducted during a 24-hour period starting on July 22, 1999 and ending July 23, 1999. The goal of the groundwater pump test was to provide aquifer data necessary to characterize the feasibility of operating a groundwater treatment system at the site. The radius of W! influence of groundwater extraction, groundwater drawdown, hydrogeologic properties of the aquifer, and the mass extraction rate of groundwater were to be determined by this pumping test. The results E of the groundwater pumping test showed the radius of influence for groundwater extraction at the site is greater than 50 feet. Hydrogeologic properties of the aquifer, specifically, hydraulic conductivity (K), transmissivity (T), and the coefficient of storage (S) were measured.. The average hydraulic f} conductivity (K) was calculated to be 0.001 meters/second, the average transmissivity (T) was calculated to be 6.79 square feet/minute, the Coefficient of Storage (S) was calculated using Cooper- Jacob solution to be 0.0015. In addition, based on analytical results of samples taken during the ' groundwater pumping test, 6,000 gallons of groundwater were extracted from the subsurface, and 0.00005 lbs. of TPHd were removed from the subsurface during the twenty-four hour test. The groundwater pumping test activities are detailed in the Summary Report of Pumping Test, dated September 19, 2000. w:162574162574.42VeportsLsup_sub_inv.doc 3