Trends in water-leachable lead from a fluvial tailings deposit along the upper Arkansas River, Colorado

Fluvial deposits of mine tailings occur along the upper Arkansas River south of Leadville, Colorado. We examined material collected from a small fluvial tailings deposit (approximately 0.1 km 2 ) located about 13 km downstream of Leadville. The deposit is predominantly barren of living vegetation. We collected continuous cores of one-inch diameter that ranged from 10 to 58 cm deep. We separated the cored material into visually distinct sections based on color and textural differences, and determined bulk chemical composition, mineralogy, and water-leachable chemical constituents for the distinct sections. There is a large reservoir of water-leachable lead in the fluvial tailings deposit. Comparison of bulk lead and water-leachable lead concentrations reveals that bulk lead concentrations are not a good indicator of water-leachable lead concentrations.