Risk of colloidal and pseudo-colloidal transport of actinides in nitrate contaminated groundwater near a radioactive waste repository after bioremediation

• Published in: Scientific reports Vol. 12; no. 1; pp. 4557 - 13
• Main Authors: Safonov, Alexey, Lavrinovich, Elena, Emel’yanov, Alexander, Boldyrev, Kirill, Kuryakov, Vladimir, Rodygina, Natalia, Zakharova, Elena, Novikov, Alexander
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 16-03-2022; Nature Publishing Group; Nature Portfolio
• Subjects: 631/158/47; 631/158/855; 631/61/168; 639/4077/4091/4094; 704/172; 704/47; Actinides; Actinoid Series Elements - analysis; Aquifers; Biodegradation, Environmental; Bioremediation; Colloids; Goethite; Groundwater; Groundwater pollution; Humanities and Social Sciences; Immobilization; Iron; Metabolites; multidisciplinary; Nitrates; Polymers; Radioactive pollution; Radioactive Waste - analysis; Radioactive wastes; Risk reduction; Science; Science (multidisciplinary); Sediments; Water analysis; Water sampling
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-022-08593-3

The possible role of biogeochemical processes in the transport of colloidal and pseudo-colloidal U, Np, and Pu during bioremediation of radionuclide- and nitrate-contaminated groundwater was investigated. In two laboratory experiments with water samples taken from contaminated aquifers before and post bioremediation, we found that microbial processes could cause clayed, ferruginous, and actinide colloids to coagulate. The main mechanisms are biogenic insoluble ferrous iron species formations (goethite, pyrrhotite, siderite, troilite, and ferrihydrite), the aggregation of clay particles by microbial metabolites, and the immobilization of actinides in the bacterial cells, large polymers, and iron and clayed sediments. This process decreases the risk of colloidal and pseudo-colloidal transport of actinides.