Superfund Research Program
Sequestration Processes for Attenuation and Treatment of Arsenic and other Toxic Elements in Mine Waters
Final Progress Reports
Acid rock drainage and its potential impact on surface-water and groundwater contamination is a primary environmental concern for many hardrock mining sites in the USA. The potential risk of mining-impacted waters to human health is a critical issue associated with hardrock mining sites. The risk is a function of exposure routes and levels, which in turn are controlled by physical and biogeochemical processes that attenuate or reduce contaminant concentrations. Microsites are localized regions in the subsurface where a majority of attenuation and transformation reactions may take place. Accurate assessments of human-health and environmental risk posed by contamination, as well as evaluation of remediation potential, requires an understanding of how these microsites form and their importance to overall fate of contaminants. Research in the past year has focused on the development and testing of methods to characterize fluid configuration and interfacial areas at the pore scale in soils and sediments that have changing water contents. These methods provide the research team with the ability to measure variables that are significant in mediating transport and fate of constituents. For example, researchers have investigated the use of x-ray microtomography and interfacial partitioning tracer tests. The outcomes will provide improved insights into the formation and status of microsites.