Study of the long-range effects of radioactive effluents from nuclear power plants in the Rhine river using 58Co and 60Co as tracers

• Published in: Journal of environmental radioactivity 1992, Vol.15 (1), p.51-68
• Main Author: Mundschenk, H.
• Format: Article
• Language: English
• Subjects: Applied sciences; Continental surface waters; Exact sciences and technology; Natural water pollution; Pollution; Water treatment and pollution
• ISSN: 0265-931X; 1879-1700
• DOI: 10.1016/0265-931X(92)90042-R

58Co and 60Co were used to trace the long-range effects of nuclear power plants in the aquatic environment of the Rhine river basin. 60Co, preferentially originating from Swiss installations, could be detected in suspended matter along the river over several hundreds of kilometres, even to the Lower Rhine. This nuclide was transferred to the bottom layer by sedimentation along the whole stretch, especially in high-sedimentation zones, which must be considered to be the so-called ‘critical impact areas’ for estimation of the radiological effects of the nuclear power plants in the aquatic environment. 58Co, mainly discharged by French and Swiss installations, could be measured in suspended matter. In sediment samples, however, this nuclide could not, or only occasionally, be detected because transfer to the sediment layer proceeded at a rather low rate relative to the decay rate of 58Co. From these findings, it follows that impact control of these nuclear power plants should not be restricted to their immediate aquatic environments but should be extended to the whole river. Estimation of the resulting radiation exposure, based on the measured concentrations of 60Co and 58Co in sediment and assuming standard conditions, showed that the dose rates generated by the most sensitive pathway, and indeed by other nuclides and different pathways, were far below the dose limit defined in German legal regulations and therefore were negligible.