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The wells will be installed with 0.02-inch perforated casing. The filter pack will be placed from 2 feet above tl'e screen interval to total depth. The bentonite seal will be placed from 2 to 4 feet above the filter pack and a bentonite/cement slurry will be placed from near surface to 4 feet above the filter pack. The wells will be secured withla lacking, water-tight cap and an 8-inch-diameter traffic-rated wellhead vault (Figure 4). Proposed wells MWA through MW-3 will be placed in the area of the former gasoline UST. Well MW-1 will be used to define the upgradient extent of petroleum-impacted groundwater while proposed wells MW-2 and MW-3 will be used to define the lateral and downgradient extent of petroleum-impacted groundwater. Proposed wells MW-4 through MW-6 will be placed in the area of the former diesel USTs on the western portion of the site. Well MW-4 will be used to define the upgradient extent of petroleum- impacted groundwater while proposed wells ,MW-5 and MW-6 will be used to define the lateral and downgradient extent of petroleum-impacted-groundwater. . The six-wells should,provide sufficient data to accurately document groundwater levels and gradient. Prior to drilling, the underground utility notification network, USA, will be contacted for identification,of buried utilities at or entering the project site from the public right-of-way. As a further precaution against drilling into or through potential buried obstructions, the first five feet of each boring will be augured by hand. Following installation, the top-of-casing elevation of each new well will'be surveyed. SOIL AND`.GROUNDWATER SAMPLING Soil samples',,will be screened in the field for selection of one soil sample from each boring to be submitted, under chain-of-custody, to a state-certified laboratory for analysis. Soil samples from borings MW=1 through MW-3 will be analyzed for: a). total petroleum hydrocarbons (TPH), as gasoline, by,modified EPA Method 8015; and b) benzene,toluene, ethylbenzene and total xylenes (BTEX) by EPA Method 8020. Soil samples from borings MW-4 through MW-6 will be analyzed for: a) TPH,"as gasoline, by modified EPA Method 8015; b) TPH, as diesel, by modified EPA Method 8015; and c) BTEX by EPA Method 8020. , Soil samples will be collected at five-foot intervals. All"'drill cuttings will be temporarily stockpiled on site, under, and on plastic sheeting, pending receipt of the analytical results. The monitoring wells will be developed, purged and sampled in accordance with the Apex SOP included in Attachment 1. Groundwater samples will be submitted, under chain-of-custody, to a state-certified'laboratory for analysis. "Groundwater 'samples from-wells MW-l'through MW-3- will be analyzed for: a) total petroleum hydrocarbons (TPH), as gasoline, by modified EPA ; Method 8015; and b) benzene, toluene, ethylbenzene and total xylenes (BTEX)'by EPA Method 602. Grouri`dwater samples from wells MW-4 through MW-6 will be analyzed for: a) TPH, as gasoline, by'Ginodified EPA Method 8015; b)TPH, as diesel, by modified EPA Method 8015; and c) BTEX by EPA Method 602. Development and purge water will be temporarily stored on site in . Department of Transportation approved 55-gallon drums pending receipt of the analytical results. Once the analytical data is reviewed and evaluated, a "Preliminary Investigation and Evaluation Report" (PIER) will be prepared. The PIER will follow Appendix A of the Tri-Regional Guidelines, and will include all results of investigation and testing conducted to date at the site.