Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
580717 | Journal of Hazardous Materials | 2010 | 8 Pages |
Abstract
This paper investigates the environmental fate of radionuclide decay chains (specially the 238U and 232Th series) being released from a conventional mining installation processing ore containing natural occurring radioactive materials (NORMs). Contaminated waste at the site is being disposed off in an industrial landfill on top of a base of earth material to ensure integrity of the deposit over relatively long geologic times (thousands of years). Brazilian regulations, like those of many other countries, require a performance assessment of the disposal facility using a leaching and off-site transport scenario. We used for this purpose the HYDRUS-1D software package to predict long-term radionuclide transport vertically through both the landfill and the underlying unsaturated zone, and then laterally in groundwater. We assumed that a downgradient well intercepting groundwater was the only source of water for a resident farmer, and that all contaminated water from the well was somehow used in the biosphere. The risk assessment was carried out for both a best-case scenario assuming equilibrium transport in a fine-textured (clay) subsurface, and a worst-case scenario involving preferential flow through a more coarse-textured subsurface. Results show that preferential flow and soil texture both can have a major effect on the results, depending upon the specific radionuclide involved.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Chemical Health and Safety
Authors
E.M. Pontedeiro, M.Th. van Genuchten, R.M. Cotta, J. Simunek,