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A" } GR Field Methods and Procedures cooler with blue ice for preservation. A chain-of-custody form is initiated in the field and accompanies the selected soil samples to the analytical laboratory. Stockpiled soils are covered with plastic sheeting after completion of sampling. Construction of Monitoring Wells Monitoring wells are constructed in the exploratory borings with Schedule 40 polyvinyl Chloride(PVC)casing. All joints are thread joined; no glues, cements, or solvents are used in well construction. The screened interval is constructed of machine-slotted PVC well screen which generally extends from the total well depth to a point above the groundwater. An appropriately-sized sorted sand is placed in the annular space adjacent to the entire screened interval. A bentonite transition seal is placed in the annular space above the sand,and the remaining annular space is sealed with neat cement or cement grout. Wellheads are protected with water-resistant traffic rated vault boxes placed flush with the ground surface. The top of the well casing is sealed with a locking cap. A lock is placed on the well cap to prevent vandalism and unintentional introduction of materials into the well. Storing and Sampling of Drill Cuttings Drill cuttings are stockpiled on plastic sheeting or stored in drums depending on site conditions and regulatory requirements. Stockpile samples are collected and analyzed on the basis of one composite sample per 50 cubic yards of soil. Stockpile samples are composed of four discrete soil samples,each collected from an arbitrary location on the stockpile. The four discrete samples are then composited in the laboratory prior to analysis. Each discrete stockpile sample is collected by removing the upper 3 to 6 inches of soil, and then driving the stainless or brass sample tube into the stockpiled material with a hand, mallet, or drive sampler. The sample tubes are then covered on both ends with teflon sheeting or aluminum foil,capped,labeled, and placed in a cooler with blue ice for preservation. A chain-of-custody form is initiated in the field and accompanies the selected soil samples tothe analytical laboratory. Stockpiled soils are covered with plastic sheeting after completion of sampling. Wellhead Surve The top of the newly-installed well casing is surveyed by a California-licensed Land Surveyor to mean sea level (M.S.L.). Well Development The purpose of well development is to improve hydraulic communication between the well and surrounding aquifer. Prior to development,each well is monitored for the presence of separate-phase hydrocarbons and the depth-to-water is recorded. Wells are then developed by alternately surging the well with the bailer,then purging the well with a pump to remove accumulated sediments and draw groundwater into the well. Development continues until the groundwater parameters (temperature,pH,and conductivity)have stabilized. Grab Groundwater Sampling A Hydropunch®groundwater sampling too]or temporary PVC casing installed in the boring may be used to facilitate grab groundwater sample collection. Samples of groundwater are collected from the surface of the water in the Hydropunch®or temporary casing using a teflon bailer. The water samples are then gently poured into laboratory- cleaned containers and sealed with teflon-lined caps,and inspected for air bubbles to check for headspace. The samples are then labeled by an adhesive label, noted in permanent ink, and promptly placed in an ice storage. A Chain-of- A-2