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KLEINFELDER <br /> B-3.3 Equipment Decontamination <br /> To reduce the potential for cross-contamination between wells, developing equipment is <br /> washed in a trisodium phosphate or non-phosphate detergent solution and rinsed in <br /> distilled water or steam cleaned prior to use in the next monitoring well. <br /> B-3.4 Well Survey <br /> The locations of soil borings and monitoring wells, and the elevation of the top of the <br /> PVC casings are usually surveyed and tied into permanent markers, if readily available. <br /> Survey accuracy is 0.1 foot for the "x" and "y" coordinates and .01 foot for the 'Y' <br /> coordinate. The depth to static groundwater is measured from a set location at the top <br /> of the PVC casing (usually the north rim). The depth of water is then subtracted from <br /> the elevation of the top of the well casing to provide a groundwater elevation for each <br /> monitoring well location. <br /> B-4 GROUNDWATER MONITORING <br /> B-4.1 Water Level Measurements <br /> Water level measurements are made in the wells prior to purging and sampling the <br /> wells. Measurement protocol is as follows: <br /> i1. Prior to obtaining water level measurements, the monitoring wells would be <br /> opened and allowed to equilibrate for a period of approximately 1/2 hour. <br /> 2. The water level probe is decontaminated in a trisodium phosphate or non- <br /> phosphate detergent wash, followed by a distilled water rinse, prior to use in <br /> each well. <br /> 3. Water level measurements are made using a conductivity-based water-level <br /> meter. Depth-to-water is generally measured from a surveyed mark on the north <br /> rim of the PVC well casing. <br /> The water level measurements are converted to elevations using the surveyed casing <br /> elevations. <br /> B-4.2 Groundwater Sampling <br /> Groundwater samples are collected from the monitoring wells at the site. The sampling <br /> protocol for each well is as follows: <br /> 1 . Down-well equipment (pumps, bailers, etc.) is decontaminated by steam <br /> cleaning, or by scrubbing in a trisodium-phosphate or non-phosphate detergent <br /> wash followed by a distilled water rinse, prior to use in each well. Bailer cord is <br /> replaced prior to use in each well. <br /> 58671.E01/ST05R1127/DH:ly Page B-5 <br /> ©2005 Kleinfelder, Inc. September 15, 2005 <br />