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Samples to be analyzed for dissolved constituents are filtered in the field using <br />0.45-pm capsule filters. The capsule filters are certified to meet EPA standards <br />for trace metal analysis. Sample bottles and sampling equipment are rinsed <br />thoroughly three times with the water to be sampled prior to sample collection. <br />Bottles pretreated with preservatives are not rinsed prior to sample collection. <br />General sample processing and treatment instructions follow. <br />Filtered samples for TDS are collected in polyethylene bottles and immediately <br />placed on ice. <br />Filtered samples for cations and metals are collected in polyethylene bottles, <br />acidified in the field with nitric acid added to obtain a pH of less than 2, and <br />immediately placed on ice. <br />Filtered samples for anions are collected in polyethylene bottles and immediately <br />placed on ice. <br />Filtered samples for nitrogen, ammonia, and phosphate are collected in <br />polyethylene bottles, acidified with sulfuric acid to a pH of less than 2, and <br />immediately placed on ice. <br />Unfiltered samples for total coliform are collected in plastic bottles containing a <br />dechlorinating agent added by the laboratory and immediately placed on ice. <br />Alkalinity is determined by the lab on unfiltered samples. The sample is collected <br />in a polyethylene bottle and placed on ice. <br />Unfiltered samples for trihalomethanes are collected in glass vials supplied by <br />the lab and pretreated with sodium thiosulfate. Vials are filled to the rim with no <br />air bubbles present when sealed. <br />Unfiltered samples for the determination of stable oxygen-18 and deuterium <br />isotopic composition are collected in polyethylene bottles. <br />9. Field personnel shall collect ten percent of the total samples for quality assurance <br />purposes (duplicate and field blank samples). Duplicate samples are collected and <br />processed in the field and analyzed to evaluate the heterogeneity of the matrices. <br />The duplicate samples are submitted to the laboratory with dummy site identifiers. <br />Field blank samples are processed in the field identically as the other samples using <br />de-ionized water as sample water. The field blank samples are submitted to the <br />laboratory with dummy site identifiers <br />10.A11 samples are to be promptly delivered to the analytical laboratory under standard <br />chain-of-custody control for analysis within the prescribed holding times. <br />2