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5 collection of the process point samples but before collection of the groundwater well samples). Specific conductance measurements were not taken at the process point samples. TR-0006 is unclear about which field measurements should be taken at the process polnts (except for temperature), but all field parameters, including dissolved oxygen and specific conductance can and should be taken. 2.2 Field Quality Control Samples According to TR-0006, the following QC samples should be collected: one field duplicate in 10 samples, one field blank in 20 samples, and one rinse blank in five (fqr groundwater and surface water samples) or 10 (for process points -- see pg. 32) samples T'ne rinse blank (taken after the coliection pond sample) was prepared by washing the barrel filter with soapy water, rinsing with tap water, ^nsing with D? water, filling the barrel filter with DI without a filter membrane and collecting the rinse blank The filter membrane is an integral part cf the filtration process and is nct rinsed before filtration of a sample. Consequently, for the rinse blank sample a filter paper should be placed in the filter barrel after the washing and rinsing stages and before the collection of the rinse blank so that the effect of the filter membrane on the sample can be determined. The DI water used for rinsing and field/rinse blanks was provided by the BMRI on-site laboratory. The DI water taken was channeled through the prefilter portion of the ion- exchange system but not through the final three columns of the ion-exchange system. There seemed to be an ample supply of "fully" deionized water, and if water from the BMRI laboratory is used again, the final DI water should be used. 23 Sample Preservation The samples were not checked after filling the bottles to ensure that they were preserved to the proper pH. Checking each bottle at the end of a sampling day with pH paper would be adequate. Cyanide samples should be preserved at pH 12, metals samples (dissolved and total) should be preserved to pH <2, total organic carbon should be preserved to pH <2, and sulfide should be preserved at pH 9. According to Table 5 in TR-0006, phosphate and nitrate+nitrite samples should be preserved with sulfuric acid, but the anions samples had no preservative and were not filtered. Samples for nitrate+nitrite and total phosphorous determinations should be preserved with sulfuric acid to pH <2. Because sulfate is determined in the anions samples, it will be necessary to collect a separate sample for RCG/Hagler, Baitly, Inc.