Radionuclide levels and distribution in grazed saltmarsh in West Cumbria

Radionuclide levels and distribution in the surface silts and vegetation of a grazed saltmarsh have been investigated as they are the basis for pathways to man via grazing animals and, to a lesser extent, wildfowl. Comparisons are made with a previously described ungrazed area in the same estuary complex. Accumulation of radionuclides appears to be primarily a physical process dominated by tidal factors. A second important influence is the physical structure of the vegetation present on the saltmarsh. The high levels of variability found within a distance of a few hundred metres, c. 20–460 pCi g−1 in the case of 137Cs, have important implications when sampling schemes are considered for research or monitoring programmes.