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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 ii <br /> achieved, .the sample should be taken when the water <br /> level in the well recovers to .i80% of its initial level. ;_ <br /> i <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 r` <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 ) concerningChain 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 /> measure, the wells shall be sampled in order of increasing <br /> contaminant concentrations as 'established by previous <br /> analysis. , <br /> r <br /> i3 <br /> , <br />