Radionuclide Contamination ofSurface Waters, Sediments, and Soil Caused by Coal MiningActivities in the ruhr District (Germany)

Abstract.   The discharge of highly mineralised mine waters withenhanced ²²⁶Ra and ²²⁸Ra activity concentrations hasaffected creeks, rivers, sediments, soils, and plants along theLippe River and its tributaries. ²²⁶Ra activity concentrations wereelevated in all water samples receiving mine water, withactivity concentrations gradually decreasing with increaseddistance from the colliery due to dilution and chemicalprecipitation of radium with barium. Increased concentrations ofradium and radium decay products were also measured in sedimentsand flood-affected soils. The sediments show an enrichment of ²²⁶Ra up to a factor of 750, whilethe contaminated soils only reach a factor of 10. In aquaticplants, a 4-fold increase in ²²⁶Ra activity concentrations wasmeasured downstream of the discharge points. The contaminationof the river banks and adjacent floodplain with radium isresponsible for enhanced gamma dose rates, which, along with theincorporation of soil by playing children, provide potentialradiation exposure to the public.