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[~ <br />Manganese (Figure 6) shows fairly consistent values since the fall of 1981, <br />except during 1984. At that time, a dramatic increase occurred upstream of TR- <br />A with significant dilution being observed at each successive monitoring point <br />along the mine area. The dilution was caused by the low concentrations <br />present in water exiting from the mine vicinity. All the manganese values <br />observed, except May, 1984, are consistent with the baseline values. The <br />' relatively high values of manganese observed at TR-C (0.13 mg/1) and TR-D <br />(0.16 mg/1) during May of 1988 did not appear to be related to mining activity <br />as an elevated concentration was not observed at TR-B (0.04 mg/1) which is <br />' immediately downstream of the active mine. <br />Orthophosphate (Figure 7), nitrite (Figure 7), unionized ammonia (Figure <br />8), and dissolved aluminum (Figure 8) were added to the monitoring program in <br />1988. All values obtained for these parameters have been low with most being <br />' below detection limits (Appendix 1). While orthophosphate showed some <br />perturbation during the 1990 sampling period, concentrations in 1991 were <br />consistent with pre-1990 trends. Since 1988, unionized ammonia concentrations <br />' have increased; these values are low, however, at slightly above detection <br />limits, and show little difference between station readings. <br /> <br /> <br /> <br />~J <br /> <br /> <br />f <br /> <br /> <br />