Natural occurring uranium nanoparticles and the implication in bioremediation of surface mine waters

Abstract

We investigated the fractionation of mobile uranium in surface water from an abandoned uranium-mining site in eastern Germany. The water samples were sequentially ultra-filtrated to fractionate uranium into different sizes and delineate the colloidal and nanoparticle from dissolve U phases. The results revealed that only 20% of total dissolved uranium filtrates were lower than five kDa (i.e. ca. 1-3 nm). Between 30-40% of the total mobile U were either associated with colloids or exist as nanoparticles. Among others, biotic activities contribute significantly to the formation of colloidal or nanoparticle U. Thus, we discuss the implication of natural occurring colloidal and nanoparticle U on bioremediation technology.