The Presence of 237Np in the Irish Sea

Abstract

Concentrations of 2 " ~ p , a long-lived radionuclide discharged under authorization from the British Nuclear Fuels Ltd. reprocessing plant at Windscale. UK, have been measured in samples of sea water, sediment and biological materials collected from the Irish Sea. The data suggest that this nuclide is concentrated by sedimentary materials in suspension to give a Kd in the region of 103 to 104, lower than those of the other transuranium nuclides previously recorded in the area. It is also accumulated by marine biological materials, occurring in internal organs such as the gonad of echinoderms, but the concentrations are relatively low compared to those of 239'240P~ and the 239'240P~/ 2 3 7 ~ p quotients are higher than those of recent discharges from Windscale. From the radiological aspect, initial calculations suggest that the presence of 237Np in fish and shellfish of the Irish Sea is of little significance, but further data are required to estimate its long-term impact.