6.B.(2) Proposal for Phase I Environmental Assessment

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anomaly. Depth can also be determined by processing the sampling interval and determining the size and comparing relative data to other objects detected. Characteristics of the underlying soils will effect the penetration of the radar through the ground. Sands and gravel offer the best results with the greatest depth penetration and clearest resolution. Whereas, dense saturated clays offer limited penetration of the radar signal. For purposes of this proposal, PES has assumed a depth limitation for the GPR of approximately 8 feet below land surface. Areas of the subject site will be scanned by GPR and delineated using varying interval grid patterns. Multiple scans in a North-South and East-West direction will be performed utilizing the GPR, looking for anomalies. Anomalies consistent with the desired targets (i.e., feeder lines, utilities, underground storage tanks) will be marked on the surface using paint or flags, as appropriate for documentation to others. All data collected will be processed for further analysis and inclusion within a Letter Report detailing the methods utilized results of the field survey, and conclusions. Task 11 -Soil Sampling via Geoprobe Methodology Once the GPR Survey has been completed and PES has made determinations as to the features identified, PES proposes to utilize Geoprobe methodologies to collect soil and groundwater samples from a total of five locations across the subject site. In lieu of specific information identifying the locations of the UST systems or other pertinent site features, PES' approach will be more broad-based, with focus on the property boundaries and central portion of the site. For each Geoprobe boring location, discrete soil samples will be collected at 5-foot intervals throughout the soil profile (anticipate water table within 30-feet of ground surface). Each soil sample interval will be screened for the presence of volatile organics by placing a portion of the soil sample into a plastic bag, allowing time for equilibration, and insertion of a photo ionization detector (PID) probe to observe a reading of "total VOCs" in parts per million (ppm). All data associated with the field screening of VOCs will be recorded for future reference (Soil Boring Logs). In addition, a portion of each discrete sampling interval will be placed into a laboratory provided glass jars for submittal to the laboratory. PES will utilize IDEM guidance Terra- Core Methods for collection of soil samples to be analyzed for Benzene, Toluene, Ethylbenzene and Xylene (BTEX), Methyl-tert butyl ether (MTBE) and Total Petroleum Hydrocarbons - Gaso-ine Range Organics (TPH-GRO). Additional analysis of TPH- ERO and Polynuclear Aromatic Hydrocarbons (PAHs) are also consistent with UST requirements for closure and will allow for a more rigorous comparison to current closure criteria. Determination of which samples are to be submitted for laboratory analyses will be made on the basis of field screening results, visual (staining), and olfactory (smell) observations. In the event that field screening does not result in elevated PID readings, or other indications of the presence of contamination, the soil sample interval immediately above the saturated zone will be submitted for analysis. A minimum of at least one soil sample from each Geoprobe location will be submitted for analysis from each of the five Geoprobe locations. All soil samples will be appropriately labeled, packed on ice and forwarded to the laboratory under chain-of-custody procedures. Temporary Geoprobe Well Installation/Non-Potable Well Sampling If water is encountered within the upper 30 feet of the soil profile, the Geoprobe borings (total of five) would be converted to temporary monitoring wells with the insertion of a 1-