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r GROUNDWATER TECHNOLOGY <br /> STANDARD OPERATING PROCEDURE <br /> CONCERNING WATER SAMPLING METHODOLOGY <br /> SOP 9 <br /> Prior to water sampling, each well shall be purged by <br /> ' pumping a minimum of four well volumes or until the <br /> discharge water indicates stabilization of temperature, <br /> conductivity,and pH. If the well is evacuated before <br /> four well volumes are removed or stabilization is <br /> achieved, the sample should be taken when the water <br /> level in the well recovers to 80% of its initial level . <br /> ' Retrieval of the water sample, sample handling and sample <br /> preservation shall be conducted in accordance with <br /> Groundwater Technology Laboratory Standard Operating <br /> Procedure (GTL SOP 10) concerning Sampling For Volatiles <br /> in Water" . The sampling equipment used shall consist of <br /> a teflon and/or stainless steel samplers, which meets <br /> EPA regulations. Glass vials with teflon lids should be <br /> ' used to store the collected samples. <br /> To insure sample integrity, each vial shall be filled with <br /> ' the sampled water such that the water stands above the lip <br /> of the vial . The cap should then be quickly placed on the <br /> vial and tightened securely. The vial should then be <br /> checked to ensure that air bubbles are not present prior <br /> to labeling of the sample. Label information should <br /> include a sample identification number, job identification, <br /> date, time, type of analysis requested and the sampler' s <br /> ' name. Chain-of-Custody forms shall be completed as per <br /> Groundwater Technology Laboratory Standard Operating <br /> Procedure (SOP 11) concerning Chain of Custody. <br /> ' The vials should be immediately placed in high quality <br /> coolers for shipment to the laboratory. The coolers <br /> should be packed with sufficient ice or freezer packs to <br /> ' ensure that the samples are kept below 4C. Samples which <br /> are received at the Groundwater Technology Laboratory <br /> above 10 C. will be considered substandard. To minimize <br /> sample degradation the prescribed analysis shall take <br /> place within seven days of sample collection unless <br /> specially prepared acidified vials are used. <br /> ' To minimize the potential for cross contamination between <br /> wells, all the well development and water sampling equip- <br /> ment which contacts the groundwater shall be cleaned <br /> between each well sampling. As a second precautionary <br /> ' <br /> contaminant <br /> ontam inanteconcentrationsWells shall easaestablishedled in dincreasing <br /> by previousconta <br /> analysis. <br /> • <br /> GN(11%1MartiH <br /> TECN%OLtK1 1%4 <br />