9410957 MARCUS Heavy metals are found within stream beds as the result of natural processes, but they also have been introduced through human activities. Concerns over the environmental damage and risks associated with the dumping of radioactive and toxic substances into streams has heightened public awareness of this problem and of the need to better understand the distribution patterns of heavy metals in stream beds and the dynamics through which they are transported in order to avoid hazards and facilitate clean-up operations. This project will measure and analyze the spatial and temporal variability of concentrations of heavy metals in gravel and cobble deposits of a southern Montana stream that passes through an area that was intensively mined over the last century. Measurements of copper, lead, arsenic, zinc, and other metals will be taken in different parts of two 200-meter reaches of this stream over a two-year period, thereby permitting analysis of seasonal variations. Analyses will be made of the form and origins of the metals, and spatial statistical analyses will be undertaken to evaluate their location patterns and associations with other factors. A model of hydraulic processes will be adapted and tested in order to determine whether variability in metal concentrations can be predicted as a function of sediment size, hydraulic conditions, and characteristics of the minerals. This project will yield new understandings with both fundamental and practical implications. The project will provide valuable new insights into the locational patterns of heavy metal concentrations in stream beds over time, and it will expand knowledge of the processes through which metals are transported and concentrated in stream deposits. This knowledge will be of immediate benefit to those people responsible for maintaining water quality, especially those assigned to monitor and restore streams that have excessive concentrations of heavy metals.
