AN EXPERIMENTAL-STUDY ON MASS LOADING OF SOIL PARTICLES ON PLANT-SURFACES

Radionuclide contaminated soil adhered to plant surfaces can contribut e to human ingestion dose. To determine this contribution, a method of Sc-46 neutron activation analysis was established and tested, by whic h a detection limit of 0.05 mg soil per g dry plant biomass can be obt ained. In the field and greenhouse experiment the mass loading of soil on ryegrass (Lolium perenne L.) and broad bean (Vicia faba L.) was in vestigated and the contribution from rainsplash and wind erosion were evaluated separately. Soil retained on plant surfaces in field conditi ons in Seibersdorf/Austria was 5.77 +/- 1.44 mg soil per g dry plant f or ryegrass and 9.51 +/- 0.73 mg soil per g dry plant for broad bean. Estimates of contribution from rainsplash and wind erosion to soil con tamination of plant during the experimental period are 68 % and 32 % f or broadbean, 47 % and 53 % for ryegrass, respectively. Mass loading r esults from field studies indicate that soil adhesion on plant surface s can contribute up to 23 % of plant Cs-132 contamination, the transfe r factors modified by mass loading decline differently, depending on C S-137 concentration of the soil and the soil mass adhered to plant sur faces.