ABSTRACT
When the Chernobyl accident occurred there was a need for rapid assessment of the geographical distribution of contamination to aid decisions on precautionary protective measures. This chapter describes some of the problems in assembling and interpreting data in such circumstances, and how computer models have been used to simulate the pathways of radionuclides from the reactor to the site of measurement to provide a coherent picture of environmental contamination. In an unplanned situation such as Chernobyl and with the spanning of many small countries in Europe, the difficulties of collecting consistent data are exacerbated. Firstly deposition of material in rainfall gave rise to an extremely patchy distribution of contamination and it was difficult to decide when measurements were taken in hot-spot areas, and when they pertained to low levels in between. Secondly there was no standard way of measuring deposition.
