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07 May 2015 • • AGE Project No. 15-3325 Page 3 of 4 SOIL-VAPOR SAMPLING Proposed soil borings may be advanced using truck-mounted or limited-access hydraulic direct-push drill rigs equipped with 1.25-inch probing rods. The drill rigs advance soil probe borings using a hydraulic hammer to drive soil and groundwater sampling tools to specified depths. Alternatively, soil borings may be advanced using a small diameter steel probe sampler with retractable screened vapor points driven into the subsurface with a mechanical hand-held hammer (rotohammer). Sampling points will be advanced to a depth of 5 or 10 feet bsg by driving a 1.5 inch tip on 1.25 inch rods to depth. The rods will then be removed and a temporary vapor probe will be attached to '/4 inch disposable polyethylene tubing. Sand will be poured to a depth of one-foot above the screen interval. Three to six-inches of dry bentonite followed by one-foot of hydrated bentonite will be placed above the sand. The remainder of the borehole will be filled with either hydrated bentonite or grout. Hydrated bentonite will be placed around the tubing at the surface to further prevent ambient air intrusion. An onsite mobile lab will be used for sample collection and analysis the next day. The mobile lab will determine the purge volume and use a tracer gas of either IPA or 1,1- difluouroethane (1,1-DFE) during field sampling activities. All samples will be run onsite following sample collection, using EPA Method 82608. Following sample collection the total VOC concentration in the sample probes will be measured using a hand-held photo-ionization detector (PID; Rae Mini-rae). INDOOR AND AMBIENT AIR MONITORING AND SAMPLING AGE proposes to collect one indoor air sample in the community center building. Indoor air samples will be collected in six-liter Summa canisters using passive integrated sampling procedures. Each canister's initial vacuum will be measured and recorded to ensure the initial vacuum is greater than 25 inches of mercury (in hg). The sampling inlet on the canisters will be connected to a mass flow controller containing a particulate filter and calibrated to 3.8 milliliters/minute (ml/min). Air samples will be collected over a period of approximately 24 hours based on the calibrated flow of 3.8 ml/min. Indoor air samples will be collected in the southwest corner of the community center room and will be placed approximately three to five feet above the ground surface in the breathing zone. The Summa canister will then be opened to begin air sample collection. Following 24-hours of sample time, the containers will be retrieved, closed, and sealed. Advanced GeoEnvironmental,Inc.