The contribution of soil adhesion to radiocaesium uptake by leafy vegetables

The Goiania accident, Brazil, was used as an opportunity to quantify the contributions of different mechanisms, in particular mass loading, leading to caesium uptake by leafy vegetables in a semi-urban environment contaminated with 137Cs. Soil splash contributions of 70-90% were quantified for lettuce and 50-60% for green cole. Soil mass loadings of 130 and 340 mg.g-1 were estimated for lettuce and 120 and 150 mg.g-1 for green cole. The results call attention to the potential significant contribution of the soil splash to radionuclide uptake by plants which have the edible plant parts near the soil surface (within 30-40 cm) and low root uptake factors. For radiological assessment purposes it could also be necessary to consider the contamination of crops by this mechanism. (orig.)