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CAMBRIA Field Screening After a soil sample has been collected, soil from the remaining tubing is placed inside a sealed plastic bag and set aside to allow hydrocarbons to volatilize from the soil After ten to fifteen minutes,a portable GasTech®or photoiomzation detector measures volatile hydrocarbon vapor concentrations in the bag's headspace,extracting the vapor through a slit in the plastic bag The measurements are used along with the field observations,odors, stratigraphy and ground water depth to select soil samples for analysis Grab Ground Water Sampling Ground water samples are collected from the open borehole using bailers,advancing disposable Tygon'�'tubrng into the borehole and extracting ground water using a diaphragm pump,or using a hydro-punch style sampler with a bailer or tubing The groundwater samples are decanted into the appropriate containers supplied by the analytic laboratory Samples are labeled,placed in protective foam sleeves,stored on crushed ice at or below 4°C, and transported under chain-of-custody to the laboratory Discrete Depth Soil and Ground Water Sampling Soil and groundwater samples are collected for lithologic and chemical analysis using a direct driven,dual tube soil coring system A hydraulic hammer drives sampling rods into he ground to collect continuous soil cores Two nested sampling rods are driven at the same time a larger diameter outer rod to act as a temporary drive casing and a smaller inner rod to retrieve soil cores As the rods are advanced the soil is driven into a sample barrel that is attached to the end of the inner rod The outer rod ensures that the sample is collected from the desired interval by preventing sloughing of the overlying material After reaching the desired depth the inner rods are removed from the boring and the sleeves containing the soil sample are removed from the inner sample barrel Sampling tubes chosen for analysis are trimmed of excess soil and capped with Teflon tape and plastic end caps Soil samples are labeled and stored at or below 4°C on either crushed or dry ice,depending upon local regulations Samples are transported under chain-of-custody to a State-certified analytic laboratory When collecting groundwater samples,the sample barrel and inner rods are removed from the boring once the targeted water bearing zone has been reached The drive casing is pulled up from 0 5 to 5 feet to allow groundwater to enter the borehole Small diameter well casing and screen is then installed in the borehole to facilitate sample collection The drive casing is then pulled up sufficiently to expose the desired length of screen and samples are collected using a bailer,peristaltic,bladder or inertial pump The ground water samples are decanted into the appropriate containers supplied by the analytic laboratory Samples are labeled,placed in protective foam sleeves, stored on crushed ice at or below 4°C,and transported under chain-of-custody to the laboratory Duplicates and Blanks Blind duplicate water samples are usually collected only for monitoring well sampling programs,at a rate of one blind sample for every 10 wells sampled Laboratory-supplied trip blanks accompany samples collected for all sampling programs to check for cross-contamination caused by sample handling and transport These trip blanks are analyzed if the internal laboratory quality assurance/quality control(QA/QC)blanks contain the suspected field contaminants An equipment blank may also be analyzed if non-dedicated sampling equipment is used •