ARCHIVED REPORTS_WELL INSTALL AND QUARTERLY GROUNDWATER MONITORING REPORT 2008

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' Well Installation and Quarterly Groundwater Monitoring Report Second Quarter 2008 1950 West Fremont Street,Stockton, California grout to approximately 1-foot bgs. A 2-inch lockable well cap was installed on the top of the well casing. A flush-mounted well box with concrete collar and covered by a lid with waterproof gasket was installed ' for each well. After completion of the fieldwork, the well locations were surveyed by Baumbach and Piazza, Inc., a California-licensed surveyor, for northings and eastings using California Coordinate System NAD 83 and elevation(NAVD 1988). 2.2.3 Well Development On June 13, 2008, the newly installed wells were developed by RSI. Each well was surged for approximately 20 minutes using a 2-inch diameter surge block attached to a winch. Following surging, fine-grained material was removed from the well using a 6-foot long, 1.5-inch diameter stainless steel bailer. A Solinst Redi-Flow 2 submersible pump was used to complete well development. The wells were developed until parameters (pH, temperature, specific conductivity and turbidity) had stabilized to within 10 percent during three consecutive measurements. Approximately 10 well volumes were removed from wells MW-1 through MW-3 during development. Well development logs are provided in Appendix C. 2.3 GROUNDWATER MONITORING AND SAMPLING On June 16, 2008, the three wells were monitored and sampled. Prior to purging and sampling, depth to static water level was measured in the three newly-installed wells using a Heron electric water level meter. Water levels were measured from a surveyed datum established at the top of each well casing and recorded on field sheets. During the investigation, groundwater sampling was conducted using new, disposable plastic bailers. Each well was purged until at least three well volumes were removed and until parameters (pH, temperature and specific conductivity) stabilized to within 0.5 degree C, 0.1 pH unit and 5 microhms during three consecutive measurements. After purging, groundwater samples were collected by transferring the groundwater sample directly from the bailers into laboratory-supplied containers with the appropriate preservatives for the analytical test methods. Groundwater samples collected for metals analyses were field filtered using a 0.45-micron filter. The filter was attached to the bailer spout with 10 mm silicon tubing. Each sample container was labeled immediately after sample collection and ' placed in a cooler with ice for transportation,under chain-of-custody protocol. ' Project 102790 5 July 2008