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`.'` 5.0 SOIL BORING AND SOIL SAMPLING PROTOCOL Soil borings and soil sampling will be performed under the supervision of a Horizon geologist. The soil borings will be advanced using a truck-mounted hollow-stem auger drill rig. To reduce the chances of cross-contamination between boreholes, downhole drilling equipment and sampling equipment will be steam-cleaned between each boring. To reduce cross-contamination between samples,the split-barrel sampler will be washed in a soap solution and double-rinsed between each sampling event. Soil sampling will be conducted in accordance with ASTM 1586-84. Using this procedure, a split- barrel sampler (California-type sampler) lined with brass sample tubes is driven into the soil at approximately 5-foot intervals by a 140-pound weight falling 30 inches. The number of blow counts required to advance the sample 18 inches will be recorded at each sample interval. Upon recovery, a portion of the soil sample will be placed in a plastic bag and sealed for later screening with an hNu type organic vapor meter(OVM). Another portion of the soil sample will be used for classification and description using the Unified Soil Classification System. One of the samples with no headspace present in the cylinder will be sealed in the brass tube with aluminum foil and a polyethylene cap, taped, labeled, and stored at approximately 4 degrees C for prompt transport to the laboratory under chain-of-custody procedures. After the soil sample is placed in the plastic bag, it will be allowed to warm, inducing volatilization of petroleum hydrocarbon vapors. The headspace vapors will be screened with the OVM. The highest observed reading will be recorded on the boring logs. Borings that are not completed as wells will be abandoned by filling with cement/bentonite grout. The grout will be tremied or pumped into the borehole. 6.0 MONITORING WELL DEVELOPMENT/PURGING AND SAMPLING Following installation,the wells will be surged with a surge block to remove fines from the and pack. After surging, ten casing volumes of ground water will be purged from each well using a bailer or centrifugal pump to remove sediment and enhance representative sample quality. Groundwater sampling events conducted after the initial well development and sampling event will be preceded by purging three well volumes as described above. After the water levels within the wells stabilize, samples will be collected with dedicated, clean, disposable plastic bailers. Samples will be contained in air-tight vials, checked for air bubbles as described above under "Groundwater Grab Samples", and then packed on ice and sent to the laboratory for analysis. Groundwater samples will be transported to the laboratory and analyzed within the EPA-specified holding time for requested analysis. Each sample container submitted for analysis will have a label affixed to identify the job number, sample date,time of sample collection, and a sample number unique to that sample. Samples will be analyzed by a California-certified laboratory. 3001-11.wp HORIZON ENVIRONMENTAL INC.