ARCHIVED REPORTS XR0010025 - Laserfiche WebLink

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GROUND ZERO ANALYSIS, INC FIELD PROCEDURES the relative consistency of the soil Sampling equipment is cleaned between each use with a steam cleaner or with clean tap water and laboratory-grade detergent Continuous core sampling during drilling with hollow stem augers is typically accomplished using a 4-inch diameter, 5-foot long split spoon sampler with no liners The soil samples selected for possible laboratory analysis are removed from the sampler and quickly sealed in their brass sleeves with Teflon tape and plastic caps Samples from the continuous core sampler are collected into 1-inch diamter brass sleeves and quickly sealed with Teflon tape and plastic caps The respective sample containers are labeled in the field with the fob number, sample location, sample depth, and date, and promptly placed in iced storage for transport to the laboratory Cham of Custody records are initiated by field personnel and accompany the samples to a laboratory certified by the State of California to perform the analyses requested "Grab" Groundwater Sampling A direct push rig or a hollow stem auger rig equipped with continuous flight, hollow stem augers is used to drill borings to the first encountered groundwater After the auger is terminated at groundwater, a Hydropunch or similar sampling device is driven into groundwater, which is allowed to flow into the sampling device Groundwater samples are slowly transferred to laboratory-cleaned sample containers, which are labeled in the field with the job number, sample location and depth, and date and promptly placed in iced storage for transport to the laboratory Cham of Custody records are initiated by field personnel and accompany the samples to a laboratory certified by the State of California to perform the analyses requested Monitoring Well Construction Monitoring wells are typically constructed in the borings with thread-jointed, 2-inch (or 4-inch) inside diameter, Schedule 40 PVC casing No chemical cements, glues or solvents are used in well construction The screened portion of each well typically consists of factory-perforated casing with 0 010 to 0 020-inch wide slots The well screen extends from the total depth of the well (typically 15 feet below the groundwater surface) to approximately 5-feet above the groundwater surface This screened interval allows sampling at the air-water interface during seasonal and other fluctuations of the groundwater level The annular space in the well is packed with sand compatible with well slot size to approximately 1- to 2-feet above the slotted interval A 2-foot thick bentonite plug is added above the sand pack to prevent the cement from entering the well pack The remaining annulus is backfilled to grade with neat cement slurry Wells are protected with a traffic-rated utility box The box has a water tight seal to protect against surface-water infiltration and must be opened with a special wrench The design of this box discourages vandalism and reduces the possibility of accidental disturbance of the well 2 groundzegormslfld-proc doe