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i C.5 WELL SURVEY The elevation of the top of the well casing is surveyed relative to an established datum using a Lietz C-3 automatic level and stadia rod. A small notch is cut in the top of the well casing to mark the survey point, to ensure that this point is used for all future water level measurements. A loop originating and ending at the datum is closed to 10.01 feet according to standard methods described by Brinker and Wolfe (1977). CA k iROUNDWATER SAMPLING The new wells are sampled no less than 24 hours after well development. C.6.1 Sg_mplingEquipment Preparation All well measurement and sampling equipment are constructed of inert material whenever possi- ble. Sampling bailers are constructed of Teflon. Stainless steel submersible or airlift pumps, surface centrifugal pumps with dedicated polyethylene tubing,or PVC bailers are used to purge the well prior to sampling.depending on depth to water. All sampling equipment is decortami- nated in the following manrer prior to introduction into each weil: 1. Bailers, pumps, suspension rope and lines, and well sounding tapes are rinsed thoroughly with clean,fresh water to remove dust and dirt. 2. All equipment is cleaned with Al( anox detergent and deionized inside and out. The equipment may be cleaned offsite and stored and transported in steam-cleaned and protected inert containers. Fluids used to decontaminate equipment on the site is stored with other purge ware*., Nitrile gloves are worn at all times during sample equipment cleaning, handling, and sample collection. 3. All equipment is thoroughly rinsed with deionized (DI) water immediately after cleaning. 4. All equipment is thoroughly rinsed with DI wzter twice before insertion into a well. 5. Bailers and pumps are suspended on clean, DI-water-rinsed polypropylene rope. The rope is discarded after each well. C.6.2 Presampling Measurement Prior to purging and sampling of each well, the depth to standing water and the total depth of the well is measured with a decontaminated optical interface probe. A decontaminated, clear acrylic bailer is then inserted into the well to just below the static water level and removed to confirm the presence/absence of any floating product. These presample measurement data are recorded on a Record of Well Gauging and Purging and used to calculate the volume of standing water in e67/97780/ape C-3