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.s I SAMPLING AND ANALYSIS PROCEDURES The sampling and analysis procedures as well as the quality assurance plan are contained in this appendix The procedures and adherence to the quality assurance plan will provide for consistent and reproducible sampling methods, proper application of analytical methods, accurate and precise analytical results, and finally, these procedures will pro\ide guidelines so that the overall objectives of the monitoring program are achieved Gi ound Water and Liquid-Phase Petroleum Hydi ocarbon Depth Assessment A water/hydrocarbon interface probe is used to assess the liquid-phase petroleum hydrocarbon {LPH} thickness, if present, and a water level indicator is used to measure the ground water depth in monitoiing wells that do not contain LPH Depth to -round water or LPH is measured from a datum point at the top of each monitoring well casing The datum point is typical a notch cut in the north side of the casing edge If a water level indicator is used, the tip is subjectively analyzed for hydi ocarbon sheen Subjective AnaIysis of Ground Water Prior to purging, a water sample is collected from the monitoring well for subjective assessment The sample is ietiietied by gently lowering a clean, disposable bailer to approximately one-half the bailer length past the air/liquid interface The bailer is then retrieved, and the sample contained Nvithin the bailer is examined foi floating LPH and the appearance of a LPH sheen Moliitorina Well Pur61n6 and Sampling Monitoring wells are purged using a pump or bailer until pH, temperature, and conductivity of the purge water has stabilized and a iminimum of three well volumes of water have been removed If three well volumes cannot be iemoz ed in one half hour's time the well is allowed to recharge to 80% of original level After rechai Jing, a ground water sample is then removed from each of the wells using a disposable bailer A Teflon bailer, electric submersible or bladder pump will be the only equipment used for well sampling When sarnples for volatile orgame analysis ale being collected, the pump flow will oe regulated at approximately 100 milliliters per minute to minimize pump effluent turbulence and aeration GIass bottles of at least 40-milliliters volume and fitted with Teflon-lined septa will be used in sampling for �olatile organics These bottles -,.A ill be filled completely to prevent air fiom remaining in the bottle A positive nneniscus forms when. the bottle is completely full A convex Teflon septum �N ill be placed over the posits-,e meniscus to eliminate air After the bottle is capped, it is inverted and tapped to verify that it contains no air bubbles The sample containers for other parameters 1�ill be filled filtered as required and capped PaL-e 1