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E 76 <br /> - A,6 GROUNDWATER SAMPLING <br /> All existing wells were gauged on 16 May 1990 and those containing water were purged and <br /> sampled. <br /> A.6.1 oampfingEquipment Preps Zion <br /> All well measurement and sampling equipment is constructed of inert material whenever possi- <br /> ble. Sampling bailers were constructed of Teflon. Stainless steel submersible or PVC bailers are <br /> used to purge the well prior to sampling,depending on the depth of the well. All sampling <br /> �w equipment was decontaminated in the following manner prior to introduction into each well: <br /> E <br /> 1. Bailers,pumps,suspension rope and lines, and well sounding tapes were <br /> rinsed thoroughly with clean,fresh water to remove dust and dirt. <br /> 2. All equipment was cleaned with Alconox detergent and deionized water <br /> } inside and out. The equipment was cleaned offsite and stored and transport- <br /> ed in steam-cleaned and protected inert containers:.Fluids used to decontam- <br /> inate equipment on the site were stored with other purge water. Nitrile <br /> gloves were worn at all times during sample equipment cleaning,handling, <br /> and sample collection. <br /> 3. All equipment wai thoroughly rinsed with deionized(DI)water immediately <br /> = after cleaning. <br /> { <br /> 4. All equipment was thoroughly rinsed with DI water twice before insertion <br /> into a well. <br /> 5. Bailers and pumps were suspended on clean,DI-water-rinsed polypropylene <br /> rope. Thn rope was discarded after each well sampling. { <br /> A.6.2 .Fresampllin„g_Measumments i <br /> i <br /> Prior to purging and sampling of each well,the depth to standing water and the total depth of the <br /> well were measured with a decontaminated optical interface probe. A decontaminated clear <br /> I -{ acrylic bailer was then inserted into the well to just below the static water 1cveI aad removed to <br /> confirm the presence or absence of any floating product. These presample measurement data <br /> i r— were recorded on a Record of Well Gauging and Purging and'used to calculate the volume of <br /> standing water in the well(one well casing volume). Measurements were made to the nearest <br /> 0.01 foot and referenced to die permanent surveyed reference point on the well casing. <br /> A.6.3 WellWell Pureina <br /> To ensure that the sample collected was as representative as possible of groundwater in the <br /> aquifer,standing water in the well and the surrounding sand pack was purged. Between one(old <br /> .,J well)and three(new well)casing volumes of well water were purged to ensure that all stagnant <br /> .A <br /> A 3 <br /> .E Earnssaxr�9a+.p. ; <br /> b_ <br />