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 pro vide 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 Pu-239,240 and Am-241 were generally at the lower end of the range of values for soil:grass transfer factors publi shed by the International Union of Radioecologists (IUR). Nevertheless , soil-associated activity dominated the concentrations observed in gr ass even when the soil content of the grass was low. Consequently, ina dvertent ingestion of soil was the important route for intakes of thes e radionuclides by the cattle. However, only about 5% of the soil-asso ciated 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 Tc-99, the observed grass:soil concentratio n ratios were lower than the generic transfer factor recommended by IU R, but were still sufficiently high such that ingestion of soil-associ ated activity was not an important contributor to intake for this radi onuclide.