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GRIO)N <br /> t� <br /> ATTACHMENT 3 <br /> FIELD INVESTIGATION AND QA/QC PROCEDURES <br /> FOR GROUNDWATER SAMPLING <br /> Groundwater Sampling Procedures <br /> The depth to groundwater and total well depth were measured before sampling using an <br /> electric water well sounder Before sampling, at least 3 casing volumes were purged from <br /> each well using a Teflon bailer Throughout purging, pH, specific conductivity, and <br /> temperature were measured and recorded for the evacuated groundwater These <br /> measurements were used to confirm that the well was purged sufficiently Water samples <br />' were generally collected after the measurements of pH, specific conductivity, and <br /> temperature had stabilized to within 10 percent of the previous readings <br /> Sampling was performed with a 1-1/2-inch-diameter disposable polyethylene bailer <br /> suspended from new nylon line The bailer was equipped with a bottom-release device <br /> Groundwater was collected with the bailer from just below the water surface in the <br /> monitoring well Water samples were collected from the bailers in new 40-milliliter glass <br /> bottles provided by the analytical laboratory The samples were collected so that no <br /> • headspace was present in the bottle The preservatives necessary for the analyses <br /> performed were provided in the glass bottles by the analytical laboratory <br /> The collected water samples were placed in sealable plastic bags and packed on ice in a <br /> portable ice chest immediately after collection Samples were delivered within 24 hours <br /> to the analytical laboratory Additional QA/QC procedures, including the use of sample <br /> identification labels and chain-of-custody forms, were followed to track sample collection <br /> and delivery <br />' Chain-of-Custody Records <br />' Cham-of-custody records were completed before the samples were packaged for <br /> shipment One copy of these records was placed in the project file The second copy <br /> accompanied the samples during transportation to the laboratory The person in the <br />' analytical laboratory who accepted responsibility for these samples signed and dated the <br /> chain-of-custody record <br />' Equipment Decontamination Procedures <br /> Water sampling equipment was decontaminated between sampling events using the <br />' following procedures <br /> 1 Rinse with water using a brush <br />' S\BFS\STOCKTON\LTR\LTR007 DOC 2/20/01 <br />