In Nevada, past studies have focused on the impact of mercury of gold mining operations upon Stillwater NWR. Environmental cotaminant specialists are conducting several studies. One is investigating the impact upon migratory birds of metals leaching into pit lakes created by excavation of ore used in cyanide heap leach gold mining. Another investigation is looking at the impact of contaminants upon recovery efforts for the Lahontan, cutthroat trout in the Truckee and Carson River Basins, and a third study is underway to evaluate the impact of elevated nutrients, selenium and other contaminants upon recovery efforts for endangered Moapa speckled dace in the Muddy River. The Muddy River is 50 miles NE of Las Vegas, originates from natural springs, and flows 26 miles to the Overton Arm of the Lake Mead National Recreation Area.