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mark the survey point, to ensure that this point is used for all future water level measurements A <br /> loop originating and ending at the datum is closed to ±0 01 feet according to standard methods <br /> (Brinker and Wolfe 1977) <br /> B 6 GROUNDWATER SAMPLING <br /> The new wells are sampled no less than 24 hours after development <br />' B 6 1 Sampling Equipment Preparation <br /> To the extent possible, well measurement and sampling equipment is constructed of inert <br /> material Sampling bailers are made of Teflon Stainless steel submersible or airlift pumps, <br /> surface centrifugal pumps with dedicated polyethylene tubing, or PVC bailers are used to purge <br />' the well prior to sampling, depending on the depth to water All sampling equipment is <br /> decontaminated in the following manner prior to introduction into each well <br />' 1 Bailers, pumps, suspension rope and lines, and well sounding tapes are nnsed <br /> thoroughly with clean, fresh water to remove dust and dirt <br />' 2 All equipment is cleaned with Alconox detergent and deionized (DI) water inside <br /> and out The equipment may be cleaned offsite and stored and transported in <br /> steam-cleaned and protected inert containers Fluids that have been used to <br /> decontaminate equipment on the site are stored with other purge water Nitrile <br /> gloves are worn at all times during sample equipment cleaning, handling, and <br />' sample collection <br /> 3 All equipment is thoroughly rinsed with deionized (DI) water immediately after <br /> cleaning <br /> 4 All equipment is thoroughly rinsed with DI water twice before insertion into a well <br />' 5 Bailers and pumps are suspended on clean, DI-water-nnsed lengths of <br /> polypropylene rope The rope is discarded after each well <br /> rB 6.2 Presampling Measurements <br />' Prior to purging and sampling, the depth to standing water and the total depth of the well are <br /> measured with a decontaminated optical or sonic interface probe A decontaminated clear acrylic <br /> bailer is then inserted into the well to just below the static water level and removed to confirm <br />' the presence or absence of any floating liquid-phase hydrocarbons These presample <br /> measurement data are recorded on a Record of Well Gauging and Purging and used to calculate <br /> the volume of standing water in the well (one well casing volume) Measurements are made to <br /> the nearest 0 01 foot and referenced to the survey reference point on the well casing <br />' WP61 73942 R01397 APB I B-3 <br />