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positive displacement(bladder) pump tubing are cleaned by heating the tubing overnight at 120° <br /> C <br /> with a low-flow, inert air source. <br /> Once the bladder pump is cleaned and reassembled, a pump blank is obtained by pumping <br /> organic-free water through the bladder p g <br /> g pump assembly. The pump effluent is sampled and <br /> analyzed by USEPA Method 601. The pump effluent analysis results must be below the method <br /> reporting limit for each parameter before the pump is taken to the site for use. <br /> During field sampling, equipment surfaces that are placed in the well or contact groundwater are <br /> steam cleaned with deionized water before the next well is purged or sampled. <br /> Water-level and Total Well-depth Measurements <br /> Immediately before a monitoring well is purged, the water level and total well depth are measured <br /> using an electric sounder as described above. The electric sounder is decontaminated by rinsing with <br /> deionized water after each use. <br /> Well Purging <br /> Standing water in the casing and gravel pack is purged from the monitoring well using a dedicated <br /> Well Wizard® bladder pump, pneumatic displacement pump, or Teflon® bailer, prior to collecting <br /> samples. Monitoring wells are purged according to the protocol presented in Figure A-1. In most <br /> cases,the amount of water purged before sampling is equal to or greater than three casing volumes. In <br /> cases where the monitoring well is evacuated to dryness prior to the removal of three casing volumes, <br /> due to the low yield of the well,the well is allowed to recharge for up to 24 hours. Samples are taken <br /> as soon as the monitoring well has recharged to a level sufficient for sample collection. If insufficient <br /> water has recharged after 24 hours, the monitoring well is recorded as dry for the sampling event. <br /> Purged water is disposed to the ground surface around the well. <br /> Groundwater purged from wells is discharged to the ground near the well but away from surface <br /> water drainage features. Discharging to the ground surface is considered common practice where <br /> the groundwater is non-toxic. <br /> Well Sampling <br /> A Teflon bailer or bladder pump is the only equipment acceptable for well sampling. Unless <br /> otherwise described, the sample containers for all parameters are filled, filtered as required, and <br /> capped. <br /> Volatile Organic Compounds(VOCs) <br /> When samples for volatile organic analysis are collected with a bladder pump, the pump flow is <br /> regulated to approximately 100 milliliters per minute to minimize pump effluent turbulence and <br /> aeration. Glass bottles of at least 40 milliliters volume and fitted with Teflon-lined septa are used in <br /> Groundwater Monitoring A-3 Department of Public Works/Solid Waste <br /> County of San Joaquin <br /> I <br />