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Sampling Methodology Proper sampling methods must be followed to assure that samples represent actual field conditions and that samples are labeled, preserved, and transported properly to retain sample integrity. This attachment describes procedures to be followed by ADR Environmental Group, Inc. (ADR), during collection of samples of subsurface soil and groundwater. Sampling procedures will be based on sampling guidance documents from the American Society of Testing and Materials (ASTM), U.S. Environmental Protection Agency (EPA), and California Department of Health Services (DHS). Actual sampling procedures to be employed will be based on field conditions and may differ from those described here. A. EXPLORATION BORING/SOIL SAMPLING PROCEDURES Soil borings and soil sampling will be performed under the direction of an ADR geologist. The soil borings will be advanced using drilling techniques appropriate for each project, as specified in the project work plan. Soil samples will be collected at maximum intervals of 5 feet. Soil sampling will be done in accordance with ASTM 1586-84. Using this procedure, three 1.06- to 2-inch-diameter, 6- inch-length, brass or stainless steel tubes are placed in a "large bore" sampler in the Geoprobe@ method. The sampler is driven into the soil using a "direct push" drilling rig. Upon recovery of the large bore sampler, the brass tubes containing the soil will be removed. One of the three tubes will be sealed at the ends with plastic end caps. The end caps will be secured to the ends of the tube to prevent loss of volatile constituents. The sample will be labeled with an identification number, time, date, location, and requested laboratory analysis. The sample will then be placed in a plastic bag and stored at approximately 4° Celsius (°C) in an ice chest for transport to the laboratory. Sample custody procedures outlined in Section E of this attachment will be followed. This will be performed for each sample collected. If proposed in an approved work plan, soil in one of the brass or stainless steel tubes will be extracted upon recovery, placed in a plastic bag, and sealed for later screening for organic vapors using a photo ionization detector (PID) or a flame ionization detector (FID). The remaining portion of the soil sample will be examined and a complete log of soil conditions will be recorded on a soil boring log using the Unified Soil Classification System. The soil will be examined for grain size, color, and moisture content. Although not anticipated, soil generated from the soil borings will be stored in 55-gallon drums (unless otherwise directed by agencies or the client) or other appropriate containers and labeled with the corresponding boring number, date, and address of the facility. B. DECONTAMINATION AND DISPOSAL PROCEDURES All equipment that comes into contact with potentially contaminated soil, drilling fluid, air, or water will be decontaminated before each use. Decontamination will consist of steam- cleaning, a high-pressure, hot-water rinse, or trisodium phosphate (TSP) wash and freshwater rinse, as appropriate.