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SAMPLING PROCEDURES Equipment Cleaning - All water samples are placed in precleaned laboratory supplied glassware. Sample bottles and caps remain sealed until actual usage at the site. Before use at the site, all equipment which comes in contact with the well or ground water is thoroughly cleaned with trisodium phosphate and rinsed with deionized or distilled water. This procedure is followed between each well sampled, and wells are sampled in approximate order of increasing contamination. A pump blank is collected prior to all sampling. Pump blanks are analyzed periodically to ensure proper cleaning. Water Level Measurements - Prior to checking for floating product, purging of the well, and sampling, the depth to water is measured in each well using a sealed sounding tape or a scaled electric sounder. Water levels are recorded in the field log book to the nearest 0.01 foot. Floating Product Thickness - A field check for floating product -is made with a clear acrylic or teflon bailer. Thickness of floating product is measured to the nearest 1/32 of an inch. Any observed film as -well -as odor and color of the water is recorded. If a teflon cord is used, the cord is cleaned. If a nylon or cotton cord is used, a new cord is used in each well. Water Sampling Procedures Immediately prior to sampling of the ground water, four well -casing volumes of water are removed. Water is removed by either bailer or submersible nitrogen -driven bladder pump. During the purging operation, purged water is monitored for temperature, pH and specific conductance. After the wells are purged and the temperature, pH, and specific conductance of the water stabilize, a water sample is collected. Samples for volatile organic and gasoline analyses are placed in EPA -approved 40 -ml containers with teflon - septa caps. Sample bottles are completely filled with water with no observed ENSCO ENVIRONMENTAL SERVICES, INC. Water Sampling Protocol Latest Revision: March 7, 1988