CORRESPONDENCE_2007 (1/07 - 6/07)

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The soil gas samples will be collected into negative -pressure stainless steel Summa canisters. After purging, each gas sample collected into the sample vessel using tubing lowered down into the interior boring. The valve on the sample vessel will be slowly opened, drawing a representative gas sample into the vessel by pressure equalization. The vacuum within the vessel will not be allowed to completely equalize to atmospheric pressure in order to ensure the integrity of the sample during shipment to the laboratory. A vacuum reading will be recorded before and after each sample is collected and annotated on the Chain -of -Custody documents. After sampling procedures are completed, the vessels will be placed into protective cases and shipped to a California -certified analytical laboratory for analysis. All vessels will be documented in the field and transported to the laboratory in accordance with EPA Chain -of - Custody protocol. Samples will be analyzed for fixed gases in accordance with ASTM method D-1946 and for VOCs in accordance with EPA method TO -14. All soil gas sampling will follow CHSL Specification Section 02670 contained in Appendix A. 2.3 Task 3 - Evaluation Monitoring Report An Evaluation Monitoring report will be prepared after the field activities are completed. The report will include the following: • A discussion of drilling methods implemented and the soil borings for the installation of the permanent groundwater monitoring wells. • A discussion of the geologic conditions encountered • Two geologic cross sections that present the subsurface conditions. • Exploratory boring logs, well construction details, monitoring well development sheets, and the Department of Water Resource forms. • A presentation and discussion of the analytical results of the investigation. The report will be prepared under the direct supervision of a California -professional geologist. Corral Hollow EMP WPlan ReQMar 22-07.DOC 2-6 March 20, 2007