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SECOR FIELD OPERATIONS PROTOCOL Groundwater Depth Measurements Prior to purging, the depth of groundwater at each well was sounded using a Solinst-brand electronic water level indicator, recorded to the nearest 0.01 foot and taken from a point of known elevation on the top of each well casing. Elevations for the top of each well casing were obtained from a level survey previously conducted by SECOR. Groundwater Monitoring Well Purging Purging of each well was accomplished using disposable, 3-foot long by 1.5-inch diameter, polypropylene bailers. A new bailer was utilized at each location to minimize the potential for cross contamination between wells. Prior to sampling each well, approximately three to five well volumes of water were removed and stored in labeled, 55-gallon steel drums. During purging operations, the groundwater temperature, conductivity and pH were measured using a Cambridge Hydac meter. In addition, the turbidity of the removed water was visually monitored and recorded. The wells were sampled after each of the three parameters had stabilized. Copies of the water sample field data sheets for each sampling episode are attached to this report as Appendix D. Groundwater Sample Acquisition and Handling Groundwater samples were obtained from each of the wells, at the air-water interface, utilizing precleaned, 1-foot long by 1.5-inch diameter, single-sample, polypropylene bailers. The water samples were collected from the base of bailers utilizing a bottom emptying device to minimize volatilization of potential contaminants. In addition,before sampling, the water level in each well casing was allowed to recharge to a minimum of 90 percent of pre- development levels. Collected water samples were placed directly into precleaned, 40-milliliter (ml) glass vials provided by the laboratory. After expelling any trapped air bubbles, the vials were sealed with Teflon-lined septum, screw-on lids. Labels containing sample number, well identification, date and time collected, type of sample, and type of preservative were then affixed to each vial. The sample vials were then placed into a cooler containing ice for delivery under Chain-of-Custody to a laboratory certified to perform hazardous waste testing by the State of California Department of Health Services (DOHS), Environmental Laboratory Accreditation Program (ELAP). Copies of the Chain-of-Custody Records are attached to this report as Appendix B. 7N 40007-097-01 LHG:WP:97-02feb\a-ma n teagwm