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Ms. Connie Davis/Aggregate Industries - F Street October 2001 QMR <br />Project Number [001018 P~R~IGON <br />November 16, 2001 <br />Page 2 <br />from the abatement excavation were discussed in the July 6, 2001 Soil and Groundwater <br />Abatement Report. <br />Installation of groundwater monitoring wells was performed at the site in July 2001 to obtain <br />information regarding groundwater quality at the site. Information regarding the assessment <br />activities and potential impacts was summarized in the October 9, 2001 Site <br />Characterization Report (SCR). The groundwater monitoring program proposed in the SCR <br />included the sampling of six (6) wells (MW-1 through MW-4, EW-l and a proposed well) <br />for benzene-toluene-ethylbenzene-xylenes (BTEX) and total extractable petroleum <br />hydrocarbon (TEPH) analyses. <br />2. WELL INSTALLATION <br />Orie (1) soil boring was completed at the site on October 15, 2001 to obtain information <br />regarding subsurface conditions. The approximate location of the soil boring, i.e. MW-5, is <br />shown on Figures 3a and 4. A Paragon field engineer was on site during the drilling <br />operations to log the boring, collect soil samples and document field activities. Split-spoon <br />sampling techniques were used to collect soil samples from boring MW-5. Soils <br />encountered while drilling were screened on site for organic vapors with a photoionization <br />detector (PID) to aid in evaluating potential zones of petroleum hydrocarbon contamination. <br />Soil samples were collected at approximate 5-foot intervals for ambient temperature <br />heatdspace analysis (ATHA). The ATHA procedure consisted of placing the soil samples in <br />Ziplock bags such that the bags were approximately one-third full. The sample was allowed <br />to equilibrate with the container headspace for approximately 15 minutes. The probe of the <br />PID was then used to pierce the bag and the maximum observed reading was recorded. The <br />ATHA results are shown on the boring log attached to this letter. PID results for soil <br />samples screened from MW-5 ranged from two (2) to eight (8) parts per million as organic <br />vapor in air. It should be noted that ATHA results are a qualitative indicator of petroleum <br />hydrocarbon contamination and should not be construed as a quantitative indicator of <br />contamination. Soil samples were not submitted for chemical analyses since the petroleum <br />hydrocarbon contamination had previously been bracketed. <br />Monitoring well MW-5 was constructed with 2-inch diameter PVC manufactured screen and <br />casing to a depth of approximately 18.5 feet below ground surface. Well construction <br />details are shown on the boring log attached to this report. The subsurface conditions <br />observed in MW-5 can be generalized as follows. Medium to coarse sand with varying <br />amounts of silt and gravel was observed from near or at ground surface to an approximate <br />depth of 19 feet below ground surface. Descriptions of the soils encountered in the boring <br />