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Ground Wake,Sampling <br /> • 2.36 Decontaminating Sampling Equipment <br /> When dedicated equipment is not used for sampling (or purging), or when <br /> dedicated equipment is stored outside of the well, the SAI' should include <br /> procedures for disassembly and cleaning of equipment before each use at each <br /> well <br /> The recommended cleaning procedure when organic constituents are of interest <br /> is as follows wash the equipment with a nonphosphate detergent and rinse with <br /> tap water, reagent grade acetone, and organic-free reagent water, in that order <br /> If acetone is an analyte of interest, a different solvent (that is not a target analyte) <br /> 1 should be chosen(e g, isopropanol) The recommended cleaning procedure for <br /> inorganic constituents of interest is as follows wash the equipment with a <br /> nonphosphate detergent/soap mixture and nnse with dilute(0 1 M) hydrochloric <br /> or nitric acid, tap water, and reagent water, in that order Dilute hydrochlonc <br /> acid with a reagent water rinse is preferred when cleaning stainless steel because <br /> nitric acid may oxidize the steel The waste decontamination fluids should be <br /> containerized and characterized to determine whether they should be treated or <br /> disposed of as hazardous waste <br /> All equipment should be allowed to dry thoroughly in a dust-free environment <br /> If the equipment is not to be used again immediately,it should be packaged and <br /> properly stored to protect it from dust and dirt Equipment may be wrapped in <br /> aluminum foil (shiny side on the outside) and placed in a plastic bag A label <br /> should be affied to the outside wrapping stating the type of decontamination used <br /> and the date of decontamination Clean sampling equipment should not be placed <br /> on the ground or on other contaminated surfaces prior to insertion in the well <br /> 23.7 Collecting Ground-Water Samples <br /> Monitoring well sampling should always progress from the well expected to be <br /> least contaminated to the well expected to be most contaminated,to minimize the <br /> potential for cross-contamination of samples that may result from inadequate <br /> decontamination of sampling equipment Samples should be collected and <br /> containerized according to the volatility of the target analytes The preferred <br /> collection order for some of the more common ground-water analytes is as <br /> follows <br /> o Volatile organics(VOAs or VOCs), <br /> U Sernivolatile organics(SMVs or SVOCs), <br /> O Magor water quality cations and anions, <br /> O Stable isotopes(e g oxygen, hydrogen, nitrogen, lead) <br /> o Metals, <br /> o Cyanide, <br /> 16 <br />