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GROUND ZERO ANALYSIS,INC. <br /> FIELD PROCEDURES FOR <br /> GROUNDWATER MONITORING AND SAMPLING <br /> Measurement of the Depth to Groundwater in Monitoring Wells <br /> The depth of the groundwater surface in each monitoring well is measured from the top of the well <br /> casing to the nearest 0.01 foot with a Solinst or similar electronic water-level indicator. The well is <br /> vented to the atmosphere before obtaining depth-to-water measurements. Venting is conducted to <br /> allow the groundwater to equilibrate to barometric pressure. These measurements are utilized with <br /> recorded well casing elevations to evaluate the elevation of the groundwater surface in each well <br /> and the slope of the groundwater surface across the site,if enough data points are available. <br /> Sampling of Groundwater Monitoring Wells <br /> The static water level in each well is measured to the nearest 0.01 foot with a Solinst or similar <br /> electronic water-level indicator cleaned with a laboratory-grade detergent and deionized water <br /> before use in each well. A clean bailer is used to obtain a sample from the surface of the water in <br /> the well for subjective analysis of hydrocarbons, if appropriate. The sample is retrieved and <br /> examined for floating product, sheen,color,and clarity. <br /> Approximately 3 to 5 well volumes are purged from each well using a centrifugal pump with V2- <br /> inch drip line, a submersible pump,or a Teflon bailer to allow sampling of representative formation <br /> water. All downhole equipment/materials are decontaminated before use in each well. The wells <br /> are purged until pH,temperature,and electrical conductivity of the water stabilized, as measured by <br /> portable meters calibrated to a standard buffer and conductivity standard. The water level is <br /> allowed to recover to at least 80 percent of the initial water level prior to sampling. Purged <br /> groundwater is contained in DOT-approved,polyethylene, 55-gallon drums pending disposal. <br /> A sample of the formation water is then collected from the surface of the water in each of the wells <br /> with a dedicated disposable bailer and slowly transferred using a bottom-emptying device to <br /> laboratory-cleaned sample containers. <br /> Equipment Calibration <br /> • Water Level Measurements in Wells: (1) Steel surveyors tape. Calibration: <br /> manufacturer supplied temperature correction will be applied as applicable for field <br /> conditions. (2) Electronic well sounders. Calibration: Once by manufacturer, then <br /> periodic check against steel surveyor's tape. <br /> • Organic Vapors-Photoionization detector. Calibration: Daily logged field <br /> calibration using isobutylene standard per manufacturer instructions. <br /> GAGROUNDZE\QAQC\FLDQM.DOC <br /> F-1 <br />