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Artesian Environmental Consultants, Inc. <br /> Standard Operating Procedures <br />' GROUNDWATER LEVEL MEASURING, PURGING AND SAMPLING <br /> Prior to groundwater sampling, static water level measurements are recorded for <br /> each well using a battery-powered sounder with a precision of plus or minus 0 01 <br /> feet. All measurements are recorded as depth-to-water from the surveyed <br /> measuring point at the top-of-casing Depth-to-water readings are converted to <br /> water level elevations referenced to the USGS mean sea level datum <br /> Then each well is purged by evacuating a minimum of three to five well-casing <br /> 1 volumes of groundwater using either a dedicated polyvinyl chloride (PVC) bailer, <br /> sterile disposable bailer or a stainless steel pump During the purging of each well <br /> and prior to sampling, discharge water temperature, specific conductivity, and pH <br /> measurements are recorded and are allowed to stabilize Stabilized measurements <br />' indicate that formation water has entered the well The groundwater sample is <br /> taken when the water level to the well recovers to 80% of its static level <br /> t Following purging, a groundwater sample is collected in accordance with <br /> Califorrua Regional Water Quality Control Board (RWQCB) procedures described <br /> an the Leaking Underground Fuel Tank(LUFT)Field Manual, the Ti i-Regional <br />' Board Staff Recommendations for Preliminary Evaluation and lnvestiganon of <br /> Underground Tank Sites , and local regulatory guidelines <br /> A groundwater sample is first collected and checked fon the presence of free <br /> product in the sampling bailer Thickness of possible free product is measured <br /> using an electronic interface probe with a plus or minus 0 01 foot detection limit <br /> Groundwater samples are collected using a pre-cleaned teflon or stainless steel <br /> bailer equipped with a ball-check valve, and sample containers are filled directly <br /> from the bailer as soon after purging as possible <br />' Agitation as manamazed during sample retrieval and sample transfer to laboratory <br /> prepared sample containers an order to minimize sample aeration Groundwater <br /> samples to be analyzed are carefully decanted into I abora to ry-prepared, 40- <br /> milliliter volatile organic analysis (VOA) vials The VOA vials are filled <br />' completely, leaving no headspace, and are capped and sealed with Teflon-lined <br /> lids Additional groundwater samples may be collected in 1 liter bottles All <br /> samples are labeled and stored in an ace chest with crashed ice to maintain a <br /> constant temperature of 4 degrees Celsius A thermometer is kept in the ice chest <br /> to ensure that the proper temperature is maintained The samples ane then <br /> delivered under chain-of-custody to a state-certified hazardous materials testing <br />' laboratory <br /> Monitor well purge water is properly stored on-sate pending off-site disposal <br /> 1 <br />