The distribution of the Chernobyl pollution in the Netherlands and an empirical relation for the transfer of radionuclides from dry and wet deposition to grass

On May the first the radioactive cloud reached the Netherlands. The time dependency of the measured total air activity in Bilthoven is shown. The gamma-exposure rate as a function of time, clearly demonstrates the dry deposition of radionuclides. On the third and fourth of May it rained, the effect of this wet deposition on the gamma-exposure rate is very pronounced. A simple model is presented to estimate the distribution of wet deposition. Results are compared with the results of a soil sampling programme. Empirical transfer factors for the transfer from wet and dry deposition to fresh grass are given. (orig./HP)