The Yenisei River and the Mining and Chemical Combine: Past releases, current conditions, and future threats

As a result of over 30 years of effluents from the Mining and Chemical Combine near Krasnoyarsk in the Russian Federation, areas of radioactive contamination along the Yenisei River have been found for over a thousand kilometers downstream. The goals of the work were to characterize the radiological status of the Yenisei River, assess potential doses from current conditions, and evaluate the potential for future contamination of the river.; The data on radioactive contamination of the floodplains, although sparse, is adequate for scoping purposes. The most significant data gap is the lack of information on hot particle contamination. The doses that could be received along the river are highest within 25 km from the point of release due to the shallow contaminated zone depth and are dominated by external exposure to contaminated floodplain soils. Annual doses in this area could easily exceed 1 mSv. The doses generally decrease downstream and are expected to be less than 1 mSv per year from all pathways after the junction of the Yenisei and Angara Rivers. The reduction of dose with distance from the point of release is considerably more pronounced than the reduction in the level of contamination due to the increased depth of the contaminated zone downstream. Doses downstream are generally driven by agricultural pathways in areas where the roots of crops can reach the contaminated zones.; Neither ongoing releases from the MCC at current levels nor migration of existing contamination in the river is likely to worsen the existing radiological situation. The primary threat to the Yenisei River would be a massive release from the surface retention basin systems or from the liquid radioactive waste pipeline. Leakage from the site for injection of liquid radioactive wastes is unlikely to result in significant contamination of the river due to very slow rate of groundwater movement and the effectiveness of sorption in retaining the injected radioactivity. However, neither accelerated flow (e.g., flow through high permeability zones), nor facilitated transport, (e.g. colloidal transport), was considered. The potential influence of these factors deserves deeper study.