SITE INFORMATION AND CORRESPONDENCE_FILE 2

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Site Background Information: Chapin Brothers Investments, Inc. Page 14 of 19 NATURAL ATTENUATION REMEDIATION EVALUATION Natural attenuation parameters detected from the site indicate low to moderate mass reduction, utilizing electron transfer and possible bio-attenuation.A comparison of data collected near the core ofthe BTEX plume and in background locations off-site indicated an expressed assimilative capacity (EAC)for the ground water at the site was estimated to be 9.0 mg/l. However,only empirical field data(analytical data)can be relied upon to reflect contaminant degradation and mass reduction.As with all estimates of mass loss,EAC does not represent actual subsurface reactions. On 14 and 15 March 2007, three soil borings (EW3through EW6) were advanced using a truck- mounted CME-85 high-torque,truck-mounted drill rig equipped with 10-inch diameter hollow-stem augers. The soil borings were advanced vertically to a depth of 31 feet and were single-completed as a ground water extraction wells (EW-4 through EW-6) utilizing schedule 40, 4-inch diameter blank polyvinylchloride(PVC) well casing and perforated,4-inch diameter PVC well casing. The screen slot was 0.020-inch between 11 feet and 21 feet bsg and screen was 0.030-inch between 21 feet and 31 feet bsg).The wells was installed by placing the PVC well casing assembly through the hollow stem of the augers to the total depth of the boring. The augers were incrementally raised as filter pack material was slowly poured down the annulus between the well casing and the inner wall of the hollow stem auger. The filter pack material placed in the wells consisted of a#3 sand from 9 feet bsg to 21 feet bsg and a 50/50 blend of fine grained aquarium gravel and#3 sand from 21 feet to 31 feet bsg. The filter pack was placed adjacent to the screened casing from the bottom of the boring to a point approximately two feet above the top of the screen. Following filter pack placement, a surge block was inserted into the well casing and was alternately raised and lowered (surged) repeatedly for approximately 20 minutes to settle the filter pack material. A nominal two-foot seal of bentonite pellets was placed above the filter pack and allowed to hydrate with clean tap water. The remaining annular space was backfilled with portland cement. INSTALLATION OF GROUND WATER EXTRACTION SYSTEM The ground water extraction system consisting of the ground water treatment unit and associated piping was installed between January and March 2002. A 1-inch diameter, schedule 40 PVC process piping and 3/4-inch diameter, schedule 80 PVC electrical piping conduit were installed in the on-site trench at approximately 18-inches bsg. A manifold PVC piping system was utilized in the trench to connect the process piping system from each extraction well head to the ground water treatment system. 4-inch diameter, stainless steel model 5S10 Grundfos Rediflow down-well pumps equipped with 230 volt Franklin V2-horsepower 3-wire motors were installed in ground water extraction wells EW-1, EW-2, EW-3, VW-6. The Grundfos pumps were installed in each well at a depth of approximately 30 feet bsg. Electrical PumpTec controller boxes were installed in the electrical control panel for individual control measures of extraction well pumps.Pump controls are supplied by an amperage sensing/time control switch.This switch will detect any decrease in amperage when water level drops below the impeller Advanced GeoEnvironmental,Inc.