The transfer of plutonium, americium and technetium along the soil-pasture-cow pathway in an area of land reclaimed from the sea

An area of reclaimed land on the Lancashire coast has been used to provide data on transfer parameters in the soil-pasture-milk pathway when the activity is almost entirely of marine origin. Measured grass:soil concentration ratios for 239,240Pu and 241Am were generally at the lower end of the range of values for soil:grass transfer factors published by the International Union of Radioecologists (IUR). Nevertheless, soil-associated activity dominated the concentrations observed in grass even when the soil content of the grass was low. Consequently, inadvertent ingestion of soil was the important route for intakes of these radionuclides by the cattle. However, only about 5% of the soil-associated activity was found to be soluble in rumen fluid, which suggests that only a small percentage of the activity ingested would have been available for uptake. For 99Tc, the observed grass:soil concentration ratios were lower than the generic transfer factor recommended by IUR, but were still sufficiently high such that ingestion of soil-associated activity was not an important contributor to intake for this radionuclide.