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K L E I N F F L D E R A, .t 3. Water level measurements are made using a conductivity-based water-level meter. Depth-to-water is generally measured from a surveyed mark on the north rim of the PVC well casing. The water level measurements are converted to elevations using the surveyed casing elevations. B-4.2 Groundwater Sampling 1 Groundwater samples are collected from the monitoring wells at the site. The sampling protocol for each well is as follows: i 1. Down-well equipment (pumps, bailers, etc.) is decontaminated by steam cleaning, or by scrubbing in a trisodium-phosphate or non-phosphate detergent wash followed by a distilled water rinse, prior to use in each well. Bailer cord is replaced prior to use in each well. 2. The depth to groundwater is measured using a conductivity-based water-level meter. 3. The volume of water in gallons standing in the well is calculated by subtracting the depth to groundwater measurement from the depth of the well and multiplying by the appropriate conversion factor(0.16 for 2-inch wells, and 0.65 for 4-inch wells). + 4. Three to five well volumes of water are purged from each well using a submersible pump, bladder pump, or Teflon bailer. 5. Physical parameters (pH, electrical conductivity, and temperature) are monitored for stability while purging. The physical parameter measurements are recorded on purge- and-sample logs, along with the time and volume of water purged at each measurement. 6_ Samples are collected with a disposable bailer or bladder pump into appropriately prepared bottles provided by the analytical laboratory. 7. Samples for metals analysis are usually filtered in the field at the time of collection. 8. Samples are immediately labeled and placed in an iced sample container. At the end of the day, the samples are delivered to the analytical laboratory under chain-of-custody k control. B-5 Vadose Zone Monitoring { 1. Prior to conducting lysimeter sampling, the pressure-vacuum equipment is checked and cleaned. A Soil-Moisture hand pump with a pressure-vacuum gage is used to measure residual and implied pressure-vacuum. Nitrogen gas is used to purge the lysimeter system for sampling. An air pump is available as a back up. 2. Approximately one week to one month prior to conducting the sampling, the residual pressures at the air-line of each lysimeter are measured ad the vacuums reset to 20-2245-36.EOi/201IR279 Page B-6 Copyright 2001,Kleinfelder,Inc March 14,2001 Y i