The effects of preferential flow and soil texture on risk assessments of a NORM waste disposal site

JOURNAL OF HAZARDOUS MATERIALS

卷:174

Article

Pontedeiro, E. M.²  van Genuchten, M. Th.¹  Cotta, R. M.¹  Simunek, J.³ 

[1] Univ Fed Rio de Janeiro, COPPE LTTC, Dept Mech Engn, BR-21945970 Rio De Janeiro, Brazil

[2] CNEN, Brazilian Nucl Energy Commiss, BR-22290901 Rio De Janeiro, Brazil

[3] Univ Calif Riverside, Dept Environm Sci, Riverside, CA 92521 USA

关键词: Radionuclide transport;    NORM wastes;    Preferential flow;    Risk assessment;    Solid waste disposal;   

DOI  :  10.1016/j.jhazmat.2009.09.100

来源: Elsevier

【 摘 要 】

This paper investigates the environmental fate of radionuclide decay chains (specially the U-238 and Th-232 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. (C) 2009 Published by Elsevier B.V.

【 授权许可】

Free