Laserfiche WebLink
22 August 2005 <br /> . AGE-NC Project No 99-0559 <br /> Page 2 of 7 <br /> Site Assessment Work Plan, dated 25 January 2001 <br /> 2,0. GROUND WATER MONITORING AND SAMPLING <br /> Ground water monitoring and sampling were performed on Ob June 2005 The work was performed <br /> in accordance with guidelines established by the California Regional Water Quality Control Board <br /> (CRWQCB) - Central Valley Division for subsurface investigation of underground storage tank <br /> (UST) sites, and with the San Joaquin County Environmental Health Department(EHD)-approved <br /> Preliminary Site Assessment Work Plan, dated 12 October 1999, and Interim Remediation and Site <br /> Assessment Work Plan, date 25 January 2001, both prepared by AGE <br /> 2 1 WELL MONITORING AND EVACUATION <br /> Depth to ground water was measured in wells MW-1 through MW-4 and well chambers A through E <br /> of the multi-level wells MW-5 through MW-7 from the top of the well casings to the nearest <br /> 0 01-foot,utilizing a Solinist water level meter, ground water elevations and gradients in this report <br /> are based on the measured depths After ground water depth measurements, well chambers A <br /> through E of the three multi-level monitoring wells were purged by lowering and raising a 3/s-inch <br /> outer diameter, length-discrete polyethylene hose equipped with a ball-valve water tip through the <br /> top chambers into the specific water-charged screened section <br /> Approximately 0 3 to 5 5 gallons of ground water (a minimum of three casing-water volumes per <br /> well screen)were removed from the monitoring well levels Temperature,pH and conductivity were <br /> measured for stabilization at regular purge-volume intervals during monitoring using an Oakton <br /> water analyzer, field data and logs are included in Appendix B Purged ground water was <br /> containerized in 55-gallon drums and processed on-site for discharge under permit <br /> 2 2 COLLECTION AND ANALYSIS OF GROUND WATER SAMPLES <br /> Prior to ground water sampling,the ground water level in each well was measured to ensure that the <br /> well achieved a minimum of 80 percent recharge Following depth measurement, ground water <br /> samples were collected from well chambers utilizing 3/8-inch diameter polyethylene tubing The <br /> ground water samples were transferred into three 40-milliliter(ml) EPA-approved volatile organic <br /> analysis (VOA) vials containing 0 5 ml 18% hydrochloric acid as a sample preservative, care was <br /> taken to ensure that visible air bubbles were not present in the vials after filling and capping Ground <br /> water sample containers were properly labeled,placed in a chilled container and transported under <br /> chain of custody protocol to Cal Tech Environmental Laboratories(CTEL),a California Department <br /> Advanced GeoEnvironmentai,Inc <br />