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ENCLOSURE A SAMPLING TECHNIQUES Proper sampling techniques 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 exhibit describes procedures to be followed - during collection of samples of subsurface soil and ground water Sampling guidance documents from the American Society of Testing and Materials (ASTM), U S Environmental Protection Agency (EPA), and California Environmental Protection Agency (Cal-EPA) will be followed for all sampling procedures Actual sampling procedures to be employed will be based on field conditions and may differ from those described here 1.0 EXPLORATION BORING/SOIL SAMPLING PROCEDURES Soil borings and soil sampling will be performed under the direction of a _ geologist The soil borings will be advanced using a truck-mounted, hollow-stem auger drill ng Soil samples will be collected at 5-foot vertical intervals Soil sampling will be done in accordance with ASTM 1586-84 Using this procedure, three 2-inch-diameter, 6-inch-length, brass tubes are placed an a California-type split-barrel sampler The sampler is driven into the soil by a 140-pound weight falling 30 inches After an initial set of 6 inches, the number of blows required to drive the sampler an additional 12 inches is known as penetration resistance, or the "N" value The "N" value is used as an empirical measure of the relative density of cohensionless soils and the consistency of cohesive soils Upon recovery of the split-barrel sampler, the brass tubes containing the soil will be removed One of the three brass tubes will be sealed at the ends with Teflon tape and plastic end caps 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 5 0 of this exhibit will be followed This will be performed for each sample collection Soil in one of the brass tubes will be extracted upon recovery, placed in a plastic bag, and sealed for later screening for organic vapors using a photoionization 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 = _ f using the Unified Soil Classification System (Enclosure A ) The soil will be examined for grain size, color, and moisture content The split-barrel sampler will be cleaned to prevent cross-contamination for each sampling interval using procedures described an Section 3 0