HR: 1340h
AN: H53F-1496    [Abstracts]
TI: Evaluation of the Transport of Natural Radioactive Materials in Large Lysimeters Using Hydrus-1D
AU: * Pontedeiro, E
EM: maypo@ucr.edu
AF: Brazilian Nuclear Energy Commision, CNEN, Rua General Severiano 90, Rio de Janeiro, RJ 22290-901, Brazil
AU: Cipriani, M
EM: cipriani@cnen.gov.br
AF: Brazilian Nuclear Energy Commission, CNEN, Rodovia Pocos de Caldas km 13, Pocos de Caldes, MG 37701-970, Brazil
AU: van Genuchten, M
EM: rvang@ussl.ars.usda.gov
AF: U.S. Salinity Laboratory, 450 W. Big Springs Road, Riverside, CA 92507, United States
AU: Simunek, J
EM: jiri.simunek@ucr.edu
AF: University of California, Riverside, Riverside, CA 92507, United States
AB: The mining industry in Brazil often uses raw materials that contain relatively high concentrations of naturally occurring radioactive materials (referred to as NORM). Ores of relatively low grade typically are used to produce refined metals of high purity (e.g., Nb, Ta, Sn, and Au) using pyrometallurgic processes. The final waste is a slag rich in natural radioactive contaminants (the U and Th decay series), which are then usually deposited in industrial landfills. To study the long-term fate and transport of radionuclides leached from the NORM wastes, several large (3 m deep) lysimeters were constructed at the Pocos de Caldas Laboratory of the Brazilian Nuclear Energy Commision (CNEN). The lysimeters were packed with surface soils and slags from one of the mining sites in South East Brazil. Main purpose of our lysimeter experiments was to follow the dissolution and transport of radionuclides from the slags under natural climatic conditions. Leaching rates and radionuclide concentrations of the effluent were observed during a three-year time period. A variety of physical and chemical properties of the soils and slags (including laboratory batch equilibrium sorption values) were also determined. The data were analyzed using several computer software packages, including the STANMOD code for analytical modeling of decay chain transport during steady flow, the HYDRUS-1D code for variably-saturated flow and the transport of multiple solutes, and the HP1 code for a more comprehensive analysis of the geochemistry involved. In this presentation we describe the experimental setup and provide preliminary results of the theoretical analyses, especially those using HYDRUS-1D.
DE: 1805 Computational hydrology
DE: 1831 Groundwater quality
DE: 1849 Numerical approximations and analysis
DE: 1875 Vadose zone
SC: Hydrology [H]
MN: 2007 Fall Meeting