ARCHIVED REPORTS_1995_1 - Laserfiche WebLink

Home Browse Search

Water levels will be measured with an electric sounder. The electric sounder is a transistorized instrument that uses a reel-mounted, two-conductor, coaxial cable that connects the control panel to the sensor. Cable markings are stamped at 1 foot increments. The water level will be measured by lowering the sensor into the monitoring well. A low-current circuit is completed when the sensor contacts the water, which serves as an electrolyte. The current is amplified and fed into an indicator light and audible buzzer, signaling when water has been contacted. A sensitivity control will compensate for highly saline or conductive water. The electric sounder will be decontaminated by rinsing with deionized water after each use. Depth to water will be recorded to the nearest 0.01 foot in the field logbook. The groundwater elevation at each monitoring well will be calculated by subtracting the measured depth to water from the surveyed elevation of the top of the well casing. The total depth of the well is then measured in the monitoring wells scheduled for sampling by lowering the sensor to the bottom of the well. The total depth of the well, used to calculate purge volumes and to determine whether the well screen is partially obstructed by silt, will be recorded to the nearest 0.5 foot in the field logbook. SAMPLE COLLECTION Sample collection procedures include equipment cleaning, water level and total well depth measurements, well purging and sampling, spring (or surface water) sampling, leachate sampling, and lysimeter sampling. Equipment Cleaning Sample bottles, caps, and septa used in sampling for volatile and semivolatile organics will be triple rinsed with high-purity deionized water. After being rinsed, sample bottles will be dried overnight at 200°C. Sample caps and septa will be dried overnight at 60°C. Sample bottles, caps, and septa will be protected from solvent contact between drying and actual use at the sampling site. Sample bottles, caps, and septa will be used only once and discarded after analysis is complete. Plastic bottles and caps used in sampling for metals will be soaked overnight in a 1 percent nitric acid solution. The bottles and caps will then be triple rinsed with deionized water, and air dried before being used at the site. All plastic bottles and caps will be constructed of linear polyethylene or polypropylene. Plastic bottles and caps will be used only once and discarded after analysis is complete. Plastic bottles and caps used in sampling for general water quality parameters are not routinely washed. They are used only once and discarded after analysis is complete. Before the sampling event is started, equipment that will be placed in the well or come in contact with groundwater will be disassembled and cleaned thoroughly with detergent SAC/pjO\0939\09390040.8el-95 lfc:3 A-2 Rev.0 February 14, 1995