Point- and nonpoint-source trace elements in a wild and scenic river of northern New Mexico

ABSTRACT:

New Mexico's upper Rio Grande and the lower 4 miles (6.4 km) of the Red River, both in Taos County, were designated as components of the National Wild and Scenic Rivers System. Almost no water quality data existed at the time these rivers were so designated. The Bureau of Land Management initiated a water quality study on these rivers in 1978 to evaluate water quality conditions and to identify and evaluate the nature, importance, sources, and effects of existing or potential pollutants. Because the major water quality threat to the wild and scenic river may be caused by mining and related activities in the Red River drainage, emphasis was placed on monitoring water quality in this river. Variations in water quality of the upper Rio Grande and Red River are presented. A downstream increase in concentrations of various constituents, at times approaching or exceeding water quality standards, occurred due to leaching of natural ore bodies and permitted discharges from molybdenum mill tailings ponds. Nonpoint sources are a major cause of elevated trace element concentrations.