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a ► <br /> GROUNDWATER TECHNOLOGY, INC <br /> 4� STANDARD OPERATING PROCEDURE <br /> CONCERNING WATER SAMPLING METHODOLOGY <br /> SOP 9 <br /> Before water sampling, each well shall be purged by pumping a minimum of four well volumes <br /> or, where required by the client and/or local implementing agency, until the discharge water <br /> indicates stabilization of temperature, conductivity, pH and turbidity If the well is evacuated <br /> before four well volumes are removed or stabilization is achieved, the sample should be taken <br /> when the water level in the well recovers to 80 percent of its initial level <br /> Retrieval of the water sample, sample handling and sample preservation shall be conducted <br /> according to Standard Operating Procedure 10 concerning "Sampling for Volatiles in Water " <br /> The sampling equipment used shall consist of a Teflonb and/or stainless steel samplers which <br /> meet U S Environmental Protection Agency (EPA) regulations Glass vials with Teflond lids <br /> should be used to store the collected samples <br /> To ensure sample integrity, each vial shall be filled with the sampled water in such a way that <br /> the water stands above the lip of the vial The cap should then be quickly placed on the vial <br /> and tightened securely The vial should then be checked to ensure that air bubbles are not <br /> present prior to labeling of the sample Label information should include a sample identification <br /> number, lob identification, date, time, type of analysis requested, and sampler's name Chain- <br /> of-custody records shall be completed by the sampler Each time the custody of samples is <br /> transferred from one person to another, each transferer and recipient must date, sign and note <br /> the time on the chain-of-custody form <br /> The vials should be immediately placed in high quality coolers for shipment to the laboratory <br /> The coolers should be packed with sufficient ice or freezer packs to ensure that the samples are <br /> kept below 4' Celsius ICI To minimize sample degradation the prescribed analysis shall take <br /> place within seven days of sample collection unless specially prepared acidified vials are used <br /> To minimize the potential for cross contamination between wells, all the well development and <br /> water sampling equipment which contacts the groundwater shall be cleaned between each <br /> sampling As a second precautionary measure, the wells shall be sampled in order of increasing <br /> contaminant concentrations {the least contaminated well first, the most contaminated well last} <br /> as established by previous analysis <br /> [sE GROUNDWATER <br /> T _ TECHNOLOGY <br />