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r <br /> t 3 <br /> • A-2 <br /> All drilling and sampling equipment will be cleaned before drilling each boring using a high-pressure, <br /> steam-cleaning apparatus. The split-spoon sampler will be cleaned with phosphate-free soap and <br /> rinsed with water following each sample collection. Soil cuttings generated during drilling operations <br /> will be placed on and covered with visquene on site until laboratory results are obtained and proper <br /> methods of disposal have been approved. <br /> 3.0 SOIL SAMPLE SCREENING <br /> After the vapors in the soil samples are allowed to equilibrate with the air.in the headspace of the <br /> plastic bags, the organic vapors within the headspace will be screened with a PTD equipped with a <br /> 10.2 eV lamp calibrated to hexane. The sample bag will be 'opened and the detector probe <br /> immediately placed within the headspace of the bag. The highest observed reading will be recorded. <br /> This number provides a relative comparison of the petroleum hydrocarbon concentration with the soil <br /> e <br /> samples but is not quantitative. The PID readings will be recorded on the boring logs. <br /> i <br /> The soil samples will be selected for laboratory analysis on the basis of organic vapor screening <br /> results and field observations. Selected soil samples will3'be submitted to a California-certified <br /> laboratory for analysis of benzene, toluene, ethylbenzene,'ixylenes (BTEX), and total petroleum <br /> hydrocarbons as gasoline,(TPH) concentrations. f <br /> y f <br /> 4.0 MONITORING WELL INSTALLATION <br /> The generalized monitoring well construction detail is illustrated in Enclosure B. Flush-threaded <br /> Schedule 40 PVC blank casing, and 0.020-inch slotted casi5I g will be used to construct the wells. <br /> Monitoring well locations are shown on the enclosed site map (Figure 2). <br /> .j <br /> Following the placement of the well casing and screen, a sand filter:pack, extending from the bottom <br /> of the screen to 2 feet above the top of the screen, will be placed in the annular space between the <br /> well screen and the borehole. A 2-foot thick bentonite pellet plug will be placed above the sand filter <br /> pack and hydrated. Cement and bentonite slurry will be placed above the bentonite plug and extend <br /> to the ground surface. Each well will be fitted with a waterproof locking cap (with lock) and covered <br /> by a water-tight protective steel well cover. ' <br /> E i <br /> k <br /> LRP 129.S]H <br />