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3 <br />Both total and dissolved samples were again collected at the three process point locations <br />for comparison of unfiltered and filtered results and to determine whether the "greenish <br />precipitate" caused analytical interferences. For the groundwater samples, total and WAD <br />ryanide and nitrate+nitrite determinations were made on unfiltered samples, while metals <br />were determined on filtered samples. This modification was made so that ithe constituents <br />that potentially interfere with cyanide determinations (nitrate+nitrite) were determined from <br />the same type of sample. <br />The following determinations performed on the samples collected for this try: total cyanide, <br />WAD cyanide, nitrate+nitrite, calcium, copper,~ron, sodium and zinc. <br />2.1 FIELD MEASUREMENTS <br />The dissolved oxygen and p13/conductivity/temperature meters were cah'bratdd each morning <br />using pH 7 and 10 buffers, 1433 µS/cm conductivity standazd and an air calibration for the <br />dissolved oxygen meter. As stated above, the pH electrode was broken on,the second day <br />of the sampling trip. Consequently, two of the groundwater samples, M-12 and M-13 did <br />not have reliable pH measurements. <br />2.2 FIELA QUALITY CONTROL SAMPLES <br />The rinse blank (taken after the collection pond sample) was prepared by wa&hing the barrel <br />filter with soapy water, rinsing with tap water, rinsing with DI water, placing a filter in the <br />barrel filter, filling the barrel filter with DI water and pulling the DI water through the filter <br />using a hand pump. <br />As on the last third-party monitoring trip, the DI water used far rinsing ,and field/rinse <br />blanks was second-stage DI water (which was finished through the final three~columns of the <br />ion-exchange system). <br />23 SAMPLE PRESERVATION <br />The process point samples were filtered using the barrel filter and disposable 0.45µm pore- <br />size filter membranes. The groundwater metals samples were filtered using in-line Gelman <br /># 12176 groundwater sampling capsules (0.45 µm pore size) that were placedldirectly on the <br />groundwater pump outlet hose. All samples were checked after collection to ensure that <br />they were preserved to the proper pH. Cyanide samples were preserved with solid NaOH <br />to pH Z12; metals samples were preserved with nitric acid to pH 52, and nitrate+nitrate <br />samples were preserved with sulfuric acid to pH<2. <br />RCG/I-Iagler, I3ailly, Inc <br />