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sensitivity control will compensate for highly saline or conductive water. The electric sounder is <br /> decontaminated after each use by rinsing with deionized water. <br /> Depth to water is recorded to the nearest 0.01 foot in the field logbook. The groundwater <br /> elevation at each monitoring well is calculated by subtracting the measured depth to water from <br /> the surveyed elevation of the top of the well casing. The total depth of the well is then measured <br /> t in the monitoring wells scheduled for sampling by lowering the sounder to the bottom of the well. <br /> The total depth of the well, used to calculate purge volumes and to determine whether the well <br /> screen is partially obstructed by silt, is recorded to the nearest 0.5 foot in the field logbook. <br /> SAMPLE COLLECTION <br /> Sample collection procedures include equipment cleaning, water level and total well depth <br /> measurements,well purging and sampling, spring(or surface water) sampling, leachate sampling, and <br /> lysimeter sampling. <br /> Field measurements are recorded on a Water Sample Field Data Sheet(Figure A-2) contained in a <br /> waterproof field logbook. Field data sheets are reviewed by the sampling coordinator after the <br /> sampling event is completed. <br /> The pH, specific conductance, and temperature meter is calibrated each day before beginning field <br /> activities. The calibration is also checked once each day to verify meter performance. Field meter <br /> calibrations are recorded on the Water Sample Field Data Sheet. <br /> Equipment Cleaning <br /> 1 Sample bottles, caps, and septa used in sampling for volatile and semivolatile organics are triple <br /> rinsed with high-purity deionized water. After being rinsed, sample bottles are dried overnight at <br /> 200°C. Sample caps and septa are dried overnight at 60°C. All sample bottles, caps, and septa are <br /> protected from solvent contact between drying and actual use at the sampling site, and are used only <br /> once and discarded after analysis is complete. <br /> Plastic bottles and caps used in sampling for metals are soaked overnight in a 1 percent nitric acid <br /> solution. The bottles and caps are then triple rinsed with deionized water and air dried before <br /> being used at the site. Plastic bottles and caps used in sampling for general water quality <br /> parameters are not routinely washed. All plastic bottles and caps are constructed of linear <br /> polyethylene or polypropylene. They are used only once and discarded after analysis is complete. <br /> Before the sampling event is started, equipment that will be placed in the well or come in contact <br /> with groundwater is disassembled and cleaned thoroughly with detergent water and then steam <br /> cleaned with deionized water. Any parts that may absorb contaminants, such as plastic pump <br /> valves, bladders, etc., are cleaned as described above or replaced. The inside surfaces of the <br /> 1 <br /> Groundwater Monitoring A-2 Department of Public Works/Solid Waste <br /> County of San Joaquin <br />