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v <br /> a A S S O C I A T E S I N C <br /> +�� ID <br /> r: <br /> `. TPHd was reported at levels ranging from non-detected (less than 1.0 ppm) to 720 ppm in soil <br /> samples collected across the site. No TPHd was detected in borings SB-7 or MW5. Results of <br /> laboratory analyses of soil samples are summarized in Table 1. <br /> Soil samples collected from depths greater than 11 feet bgs were within the saturated zone. <br /> is<=3 Analytical results of those samples are more indicative of groundwater contamination rather than <br /> soil contamination. Results of soil samples collected in the vadose zone (less than 11 feet deep) <br /> =; suggest that shallow soil contamination is somewhat random and not laterally continuous across the <br /> site. Furthermore, no BTEX constituents are present at significant levels. <br /> In September 1999, ATC supervised the advancement of soil borings SB-11, SB-12, and SB-13 at <br /> locations approximately 15 feet northwest, south, and northeast of well A W4, respectively. <br /> ' Analytical data indicated the groundwater sample from soil boring SB-12 was impacted with TPHd <br /> at a concentration of 24,000 ppb. The groundwater samples from SB-11 and SB-13 contained very <br /> low to nondetectable concentrations of TPHd. Results of laboratory analysis performed on selected <br /> � soil samples indicate that TPHd was resent in only the samples collected between 14 and 16.5 feet <br /> �=:� p p Y p <br /> bgs. Field observations indicated that the samples at these depths also exhibited the highest FID <br /> =s measurements. Soil samples SB11-15.5, SB12-16.5, and SB13-14.0 contained detectable <br /> ==` concentrations of TPHd at 390 ppm, 290 ppm, and 1,100 ppm, respectively. All the remaining soil <br /> samples were nondetect. The September 1999 subsurface investigation activities are detailed in <br /> ATC's Summary Report, Subsurface Investigation, dated January 10, 2000. <br /> A groundwater-pumping test was conducted during a 24-hour period starting on July 22, 1999 and <br /> ending July 23, 1999. The goal of the groundwater pump test was to provide aquifer data necessary <br /> :.� to characterize the feasibility of operating a groundwater treatment system at the site. The radius of <br /> t_ influence of groundwater extraction, groundwater drawdown, hydrogeologic properties of the <br /> aquifer, and the mass extraction rate of groundwater were to be determined by this pumping test. <br /> The results of the groundwater-pumping test showed the radius of influence for groundwater <br /> extraction at the site is greater than 50 feet. Hydrogeologic properties of the aquifer, specifically, <br /> hydraulic conductivity (K), transmissivity (T), and the coefficient of storage (S) were measured. <br /> : ! The average hydraulic conductivity (K) was calculated to be 0.001 meters/second, the average <br /> transmissivity (T) was calculated to be 6.79 square feet/minute, the Coefficient of Storage (S) was <br /> calculated using Cooper-Jacob solution to be 0.0015. In addition, based on analytical results of <br /> samples taken during the groundwater pumping test, 6,000 gallons of groundwater were extracted <br /> from the subsurface, and 0.00005 lbs. of TPHd were removed from the subsurface during the <br /> twenty-four hour test. The groundwater pumping test activities are detailed in the Summary Report <br /> of Pumping Test, dated September 19, 2000. <br /> $r <br /> w:IWordprol62574162574.021Reportslwell_inslall,doc 3 <br /> �1� <br />