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<br />samplings (twenty-minute time period) and these samples will all be <br />composited in the same five-gallon bucket. <br />Prior to filtering the sample, each sample should be tested with <br />lead acetate paper to determine if sulfide is present. If sulfide <br />is determined to be present, it shall be removed by the addition of <br />cadmium nitrate powder until a negative spot-test is obtained. <br />Once it has been determined that either sulfide is not present, or <br />it has been removed by the addition of cadmium nitrate, the sample <br />is then filtered through a 0.20-micron filter, and the aqueous <br />solution is collected and preserved with sodium hydroxide to a pH <br />of 12 (Table 5). <br />After each use, the bucket will be cleaned using the prlocedures as <br />outlined in this protocol. The cleaning procedure willlbe quality- <br />' controlled as outlined under the "Field Quality Control" sectiAn (Section <br />3.3). <br />' Following a sampling series of no more than five samples, a rinse <br />blank will be collected from the bucket, running laboratory- <br />provided de-ionized, distilled water throughout the entire bucket. <br />Analysis of this rinse blank will be used to validate cleaning <br />procedures. <br />Immediately after collection, all samples must be played in iced <br />coolers. The sample bottles required for each samplle site are <br />listed in Table 5 (metals, cyanide) . Sample preservation, pre- <br />treatment and holding •times, as outlined in Table 5, will be <br />strictly adhered to. <br />4.2.6 Tailings and Collection Pond Samolin~ Method: Samples will be collected <br />r from the upper impoundment area, the lower impoundment area and the <br />collection pond feeder ditch after the sampling apparatus has been <br />' cleaned in accordance with the procedures described in Section <br />i -28- <br />~~~~Y <br />w" 1~c:"-~ <br />l~ <br />