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3.0 WATER QUALITY Appendix B presents the ground-water quality data for the Trapper Mine. Table B-1 tabulates the available water quality for the Trapper monitoring wells. Total dissolved solids (TDS) wets selected, in the place of conductivity, as the parameter to discuss trends of major constituents. 3.1 TDS TDS is a measurement of the total dissolved minerals in water. it typically correlates well to constituents which make up the majority of the dissolved solids and, therefore,.i.s a good indicator of trends for the constituents. Conductivity is typically a good indicator of TDS and in turn a good indicator of some major constituents. The first series of pages for each. well presents the TDS, conductivity, and sum of major constituents (:DSSUM), along with several other parameters. DSSUM was calculated by adding the concentrations of the major cations to the major anions, except for one-half of the bicarbonate which is not aijded because this concentration is evaporated during the measurement of TDS.' This allows a comparison of TDS and DSSUM, which is a good check on the TDS and major constituent measurements. The second seeries of parameters presented in Table B-1 includes values of the charge balance (BALNC) of the major constituents. BALNC is calculated a~; the difference of the cations to anions in meq/1 divided by their sum times 100. BALNC is also a good indicator of accuracy of major constituents and values between -10 and 10 are considered good. Figure B-1 of Appendix B presents the TDS plot for well GA1. Concentrations of TDS in water from the QR aquifer in this area have been fairly steady since 1974, at a concentration o:E approximately 800 mg/1. Two of the TDS measurements are outliers and are likely erroneous. Well GA2 has been used to monitor the RLM at this site. Figure B-2 shows the TDS for this well with time. A similar TDS to that observed for water from well GA1 is shown for well GA2. Figure B-3 presents the TDS plot for the Third White Sandstone well GB2. This plot shows a fairly steady TDS for this aquifer at this location until 1982 when the concentration was significantly less than most of the previous measurements. An increa:~e in concentration has occurred in the last three years where the TDS concentration is presently approximately one-third higher than prior to the increasing trend. This increase is probably caused by mining, but is within the natural range of variation with time. Additional monitoring of this well will be useful in defining the cause of the increased TDS concentration. The TDS concentration, at this location in the HI aquifer, has not varied as it has in the Third White Sandstone. \ 3-1