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10 October 2000 AGE-NC Project No. 99-0592 Page 2 of 3 WELL SAMPLING Groundwater sample collection will be performed in accordance with PHS-EHD and CVRWQCB sampling protocols. Prior to purging and sampling,the static water level will be measured using an electric water level indicator. Water level data will be recorded to the nearest 0.01 foot from a reference point marked on the top of the PVC well casing. Before and after each use,the measurement device will be rinsed with water. Subsequent to measurement of depth to water and prior to sampling,the well will be purged using a disposable bailer to ensure that the sample is representative of the formation, rather than water standing in the well casing. The well will be purged until: 1)a minimum of three casing volumes is removed from the well; and 2) the field-measured ground water parameters have stabilized. However,if the well is purged dry prior to evacuating three casing volumes,a ground water sample will be collected following 80 percent recovery of ground water within the well or within 8-hours of well evacuation. Water samples will be collected from the monitoring wells using a disposable polyethylene bailer. These bailers are disposed of after one use and require no decontaminating, therefore minimizing cross contamination due to sampling devices.Samples will be drawn and collected in such a manner that agitation and exposure of the groundwater to the atmosphere is minimal. Sample containers will be filled using the appropriate disposable sampling attachment which allows controlled flow out of the bottom of the bailer by lifting the check valve. Ground water samples will be collected into laboratory supplied containers. Ground water samples for TPH-g and BTEX analyses will be collected into 40-m1 VOA vials containing 0.5-m1 of hydrochloric acid as preservative. Samples for TPH-d analysis will be collected into unpreserved 1-liter amber glass container. Following collection the samples will be appropriately labeled and placed on ice and kept in a cooler until delivered to the laboratory for analysis. Chain-of-custody protocols will be used to document sample custody transfer from the field to the analytical laboratory. A chain-of-custody form will accompany the samples. DOWN-HOLE VIDEO Since well construction details are not readily available for the domestic water well DW-1, a down- hole camera video-probe is proposed to identify the screened interval of the well and to assess the integrity of the well and determine well construction specifications. The down-hole video will be Advanced GeoEnvironmental,Inc.