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C RIIN <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 peristaltic pump. 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 collected after the measurements of pH, specific conductivity, and temperature had <br /> '-' stabilized to within 10 percent of the previous readings. <br /> Sampling was also performed with the peristaltic pump and vinyl tubing. Water was <br /> decanted into new 40-milliliter glass bottles provided by the analytical laboratory. The <br /> samples were collected so that no headspace was present in the bottle. The preservatives <br /> ` necessary for the analyses performed were provided in the glass bottles by the analytical <br /> laboratory. <br /> �.r 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 36 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 /> Chain-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 /> Documentation Procedures <br /> Orion personnel and subcontractors followed documentation procedures developed for <br /> site investigation work to (1) provide a record of the activities performed in the field and <br /> (2) provide identification of samples and track their status in the field, during shipment, <br /> and at the laboratory. <br /> V <br /> F+� <br /> r <br /> 5:\6FS\STOCKTON\LTR\LTR010.DOC 6/27/01 <br /> V <br />