Geochemistry of uranium in Black Sea sediments

Shows that U is depleted in the upper few centimeters of the sediment column, decreasing from the overlying water value to <0.5 dpm ²³⁸U l^-1. Removal of U from sediment pore water supports a diffusional flux of U across the sediment-water interface. Authigenic solid phase U concentrations are found to increase with depth at the central basin stations, reaching activities of 10-14 dpm g^-1. An outer shelf site, characterized by a high sediment accumulation rate, shows no apparent U accumulation in the solid phase. -from Authors