Soil contamination with Sr-90 in the near zone of the Chernobyl accident

Representative large-scale soil sampling on a regular grid of step width ab out I km was carried out for the first time in the near zone of the Chernob yl accident (radius 36 km). An integrated map of terrestrial Sr-90 contamin ation density in the 30 km exclusion zone (scale 1:200,000) has been create d from the analysed samples. Maps of the main agrochemical characteristics of the soils, which determine the fuel particle dissolution rates and the c ontamination of vegetation, were produced. The total contents of 90Sr on th e ground surface of the 30 km zone in Ukraine (without the reactor site and the radioactive waste storages) was about 810TBq (8.1 x 10(+14) Bq) in 199 7, which corresponds to 0.4-0.5% of the Chernobyl reactor inventory at the time of the accident. This assessment is 3-4 times lower than previous esti mates. (C) 2001 Elsevier Science Ltd. All rights reserved.