Uranium in Municipal Solid Waste Landfill Leachate

Landfill leachates and leachate sediments were investigated in order to survey the discharge of uranium (U) from municipal solid waste (MSW) landfills and municipal solid waste incinerator (MSWI) bottom ash landfills. Concentrations of U in the leachates were as high as or higher than concentrations of Cd, a metal more often discussed when considering the environmental effects of landfill leachate. However, the U concentrations in leachate were no greater than levels occurring naturally in water. The U concentrations in leachate sediments were also the same as or lower than those reported in lake sediments around the world. Size charge fractionation of U in freshly sampled leachate showed that the metal was present mainly as either non-labile dissolved complexes or free anions, which have intermediate to high mobility and eco-toxicity. This is in contrast to other heavy metals, such as Cd, which are generally particulate bound in leachate. However, based on all the results of the investigations, it was concluded that leaching of U is not of major concern in MSW and MSWI bottom ash landfills.