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. CjeoregkarTmcmics inc. Page 2 Former Moresco Property Report- Remedial Action Project No.: 251.3 February 6, 1998 2.1 System Installation 2.1.1 Soil Borings On September 18, 1997, four (4) soil borings were advanced. They were drilled to 45 ft below r grade which were then converted into one vapor extraction well (VEW-1) and three air recharge wells (AR-1, AR-2 & AR-3). The soil borings were drilled using a 10.25 inch outside diameter (o.d.), continuous flight, hollow stem auger owned and operated by V&W Drilling (C57# r 720904): VEW-1 was placed in the former UST pit while the air recharge wells were placed 20 1� to 25 feet out from VEW-1 in a radial pattern. The local regulatory agency was notified 48'hours prior to commencing work. The subsurface was cleared of underground utilities by notifying Underground Service Alert. r . Soil cuttings and drilling decontamination water.:were placed in DOT-17 55 gallon drums and moved to a fenced area until there disposal can be'arranged. 2.1.2 Soil Sample Collection Soil samples were collected for geological and analytical evaluation;at five foot intervals. A boring log providing sediment description. using the U.S.C.S. and field observations was . maintained by a professional geologist working under the supervision`of a registered geologist. Soil samples were collected in 6.0 inch brass liners using a 2.0 inch modified California split spoon sampler. All soil samples were sealed with Teflon sheets, capped with plastic end caps, labeled, and placed in a cooler at 4° Celsius°for transport to the laboratory following Chain of Custody protocol. Borehole logs are included in Appendix C. Because every soil sample collected was not submitted for laboratory analysis, a screening process was used to gather additional information through field observation noting sediment type, especially grain size and clay content; moisture content; visible evidence of contamination, i.e., color change due to reduction of iron or discoloration from hydrocarbons and other pollutants, and the readings above background on a organic vapor meter (OVM). The OVM is a F field portable photo ionization detector that uses a 10.0 eV lamp to detect compounds with ionization potential below 10.0 eV (hydrocarbon range). 2.1.3 Laboratory Analysis Based on field screening observations up to two soil samples from each borehole were submitted t� to Sherwood Laboratories of.Hilmar (State Certified Laboratory #1400) for analysis for benzene, toluene, ethylbenzene and xylene (BTEX by EPA method 8020), rilethyl tertiary butyl ether (MTBE by EPA method 8020) and gasoline range petroleum hydrocarbons (TPH-Gasoline by ',. EPA method 8015(m)). The detection limits for these compounds are'listed below. A Chain of Custody was completed for all samples,collected and tracked to ensure sample integrity. DetectionLimits: BTEX MTJJE ITH-Gasoline of (pg/&g) The results showed high levels of.BTEX, MTBE and TPH-G in the soil at VEW-1. All soil samples collected from the recharge wells were non-detect for all analytes. Table 1 of Appendix A summarizes this data. The laboratory data sheets are included in Appendix B. 2.1.4 Well Construction VEW-1 was constructed using 4.0 inch diameter PVC casing with flush threads and.the recharge wells were constructed using 3.0 inch diameter PVC casing. The screened intervals extended C from 25 to 45 feet below ground surface (bgs). Groundwater was not encountered. A pea-gravel ,