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All augers, screens, casing and bottom caps were steam cleaned prior to use in the wells. All grout was placed under the supervision of a San Joaquin Local Health District - Environmen- tal Health Division representative. Appendix D - Monitor Well logs presents the lithologies encountered, including first occurrence of saturated materials and well construction details specific to each well. Soil samnl inJc During the drilling of the monitor well boreholes, soil samples were collected from each location at ground surface and at 5 foot intervals thereafter down to groundwater. All samples were examined for any staining and odors which could be a result of contact with suspected contaminants. Additionally, all samples were screened with a photoionizer. (The instrument used was an HNu model P101 equipped with an 11.7 eV bulb. Before first use, the unit was allowed to warm up for approximately 5 minutes, zeroed, calibrated to isobutylene as benzene at a span setting of 5.08 and re-zeroed. Each day thereafter, the unit was warmed up and zeroed. The unit was fully charged overnight before use each day. ) No samples appeared contaminated and no readings above background were recorded on any samples. Consequently, only the two samples closest to groundwater at each well borehole. were • submitted for chemical analysis. One sample, taken at monitor well MW-3 from a depth of 35 feet below ground surface (BGS) was submitted as a duplicate sample, numbered MW3-135A. The sample was taken from the brass tube adjacent to that of the primary sample, MW3-35A. The laboratory was not informed that the sample was a duplicate so that the procedure would serve as a check on consistency of laboratory methods. Prior to collection of these samples, the split-spoon was decon- taminated by scrubbing with a bristle brush in a solution of -. potable water and non-phosphate detergent (Borax) , followed by potable water rinse and completed with a final spray rinse of distilled water. The split-spoon was then lined with laboratory w: cleaned brass tubes. Once the split--spoon had been driven into the ground andre- trieved, the spoon was opened, screened with an HNu photoionizer -- and inspected for staining and odors. As no samples appeared contaminated, chemical analytical samples were collected only upon nearing depths at which groundwater was anticipated. Soil from tubes not submitted for chemical analysis was used to — - -- -provide-3ithologicinformation---For-those samples collected far _- T T _- possible chemical analysis, two of the brass tubes were removed. - The ends of each tube were covered with teflon sheeting and then C - 2