ARCHIVED REPORTS XR0000768 - Laserfiche WebLink

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y SII •I Plastic bottles and caps used in sampling for metals will be soaked overnight in a 1 percent nitric acid solution Next, the bottles and caps will be triple rinsed with deionized water Finally, the bottles and caps will be air dried before being used at the site Plastic bottles and caps will be constructed of linear polyethylene or polypropylene Sampling containers will be used only once and discarded after analysis is complete Glass and plastic bottles used by SECOR to collect groundwater samples are supplied by the laboratory Before the sampling event is started, equipment that will be placed in the well, or will come in contact with the groundwater, will be disassembled and cleaned thoroughly with detergent water, and then steam cleaned with deionized water Any parts that may absorb contaminants, such as plastic pump valves, etc , will be cleaned as described above or replaced During field sampling, equipment surfaces that are placed to the well or contact groundwater will be steam cleaned with deionized water before the next well is purged or sampled Soil samples are collected in new, pre-cleaned brass liners These sample liners are either used by themselves, or are inserted in the sampling equipment Soil samples are not collect with or in reusable equipment Groundwater and Liquid-Phase Petroleum Hydrocarbon 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 groundwater depth in monitoring wells that do not contain LPH Depth to groundwater or LPH is measured from a datum point at the of each monitoring well casing The datum point is typically a notch cut in the north side of the casing edge If a water level indicator is used, the tip is subjectively analyzed for hydrocarbon sheen Sub ective Analysis of Groundwater Prior to purging, a water sample is collected from the monitoring well for subjective assessment The sample is retrieved 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 within the bailer is examined for floating LPH and the appearance of a LPH sheen Monitoring Well Purging and Sampling If the depth to groundwater is above the top of the screens of the monitoring well, then the wells are purged Monitoring wells are purged using an electrical submersible pump or bailer until pH, temperature, and conductivity of the purge water has stabilized and a minimum of three well volumes of water have been removed Wells are typically purged at a rate of 1 gallon per minute (gpm), though will not exceed 2 gpm If three well volumes can not be removed in one half hour's time the well is allowed to recharge to 80% of the original level After recharging, a groundwater sample is then removed from each of the wells using a disposable bailer Groundwater purged from the monitoring wells are typically transported to a holding facility in West Sacramento A Teflon bailer will be the only equipment used for well sampling When samples for volatile organic analysis are being collected, the flow of groundwater from the bailer will be regulated to minimize turbulence and aeration Glass bottles of at least 40-milliliters volume and fitted with Teflonrm- lined septa will be used is sampling volatile organics These bottles will be filled completely to prevent air from remaining in the bottle A positive meniscus forms when the bottle is full A convex Teflon 7M septum will be placed over the positive meniscus to eliminate air After the bottle is capped, it is