Laserfiche WebLink
11 <br /> 26 February 1996 <br /> AGE-NC Project No 95-0137 <br /> Page 2 of 3 <br /> On 14 August 1995, five additional soil bonngs were drilled at the site under the direction of AGE <br /> Two of the borings were completed as ground water monitoring wells Petroleum hydrocarbons were <br />' detected in soil samples collected during the investigation at concentrations as high as 1,900 parts per <br /> million (ppm, reported as milligrams per kilogram), hydrocarbons were detected in ground water <br /> samples at concentrations as high as 450,000 parts per billion (ppb, reported as micrograms per liter) <br /> 3.0. PROCEDURES <br /> 1 3 1 MONITORING WELL PURGE PROCEDURES <br /> On 29 January 1996, a Solinst water level meter was used to measure the depth to ground water in <br /> wells MW-1 through MW-5 The relative potentiometric level in each well and hydraulic gradient <br /> were calculated from these data (Table 1) Each monitoring well was purged of approximately 10 <br />' gallons of water (a minimum of three well volumes) using a pre-cleaned, two-stage, submersible <br /> pump Temperature, pH, and conductivity were measured at approximately one-gallon intervals using <br /> an ICM Water Analyzer Model No 52200 Purge water stabilization data and field data sheets are <br /> included in Appendix A The purged water was stored on-site in 55-gallon drums <br />' 3 2 GROUND WATER SAMPLE COLLECTION <br /> t After stabilization, water samples were collected from each well using new, clean, disposable Teflon <br /> bailers The samples were transferred into 40-n71 EPA vials and I-liter amber bottles and subsequently <br /> transported in a chilled container, under chain-of-custody, to Alpha Analytical Laboratory(AAL), <br /> in Ulaah, California The samples were analyzed for TPH-g, TPH-d and BTE&X in accordance with <br /> EPA methods 5030/80I5, 503018015m and 602, respectively <br /> 4.0. FINDINGS <br /> 4 1 GROUND WATER GRADIENT AND FLOW DIRECTION <br /> Figure 3 illustrates the relative ground water elevation on 29 January 1996 Depth to ground water <br /> ' at the site ranged from 19 46 to 21 05 feet bsg The data indicates a decrease of approximately 0 5 <br /> feet ground water elevation in each well since December 1995 <br /> Histoncally, the ground water flow direction at the site has varied from northwest to southeast at a <br /> very shallow gradient During October 1995, the ground water gradient was calculated to be 0 00078 <br /> ` ft/ft, flowing southwesterly Based upon data collected in January 1996, ground water gradient at the <br /> site was calculated to be 0 0056 ft/ft (29 57feet per mile), with a southerly flow direction <br /> 1 <br />