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II �5l <br /> f <br /> XLEINHI.DER <br /> } <br /> laboratory(California Analytical Laboratories/Enseco)- The remaining soil samples will <br /> -� be retained in refrigerated storage for future reference or analysis. <br /> i <br /> To minimize cross-contamination, augers and associated equipment will be steam cleaned <br /> ,i <br /> prior to the drilling of each borehole. The sampling equipment will be cleaned with a r <br /> trisodium phosphate wash and distilled water rinse prior to the collection of each soil <br /> sample. <br /> 3.2 QUALJTAnVE FIELD SCREENING , <br /> S , <br /> r.K A Photovac TIP using a photoionization detector (PID) will be used to screen each soil f <br /> sample collected from the borings. The PID field screening of the soil samples should <br /> provide a qualitative indication of the presence of petroleum hydrocarbons. The PID <br /> measures total ionizable compounds in air in parts per million by volume (ppmv) in { <br /> relation to a select calibration standard. Selection of samples to be submitted for chemical 1' <br /> i a analysis will be based on visual observations and PID screening results. , <br /> j For the protection of the field crew, the PID will also be used to measure the total volatile <br /> concentrations in the breathing zone prior to and during the drilling of the soil borings. <br /> 3.3 MONITORING WELL CONSTRUCTION i <br /> Petroleum hydrocarbons were indicated at a depth of 19 feet and the depth to ground 1 <br /> water is estimated to be 20 to 25 feet below the ground surface. Meinfelder recommends <br /> r ! l z <br /> three ground water monitoring wells be installed to assess the presence of petroleum <br /> hydrocarbons in the shallow ground water. An attempt should be made to place one { <br /> monitoring well upgradient and two monitoring wells dowugradient of the underground j <br /> storage ti..A. It is anticipated that the ground water flow is generally to the north or <br /> : northeast. The ground water flow direction will be assessed after the wells are installed. <br /> hY 't <br /> A ground water monitoring well will be constructed in the last soil boring at the end of the <br /> three radial lines. To minimize introduction of contaminants into the underlying ground <br /> water, monitoring wells will not be installed in borings where a high concentration of <br /> petroleum hydrocarbons is indicated. Tentative locations for the three ground water t <br /> t monitoring wells are shown on Plate 2. The actual locations of the wells will be selected in <br /> the field. r <br /> i <br /> S <br /> " 148-88-2109 j <br /> p <br /> MION imp <br /> i <br /> Y <br />