137Cs distribution on the territory of Romania 30 years after Chernobyl accident

To estimate the contribution of Chernobyl Cs-137 contamination, in 1993 and especially 2016, its total inventory was determined by gamma-ray high-resolution spectroscopy in 62 and respectively 747 soil samples covering the entire Romanian territory. This permitted to estimate the Cs-137 inventory as varying between 0.4 and 187 as well as between 0.2 and 94.2 kBq/m(2) for years 1993 and 2016, respectively. By representing the spatial distribution of Cs-137 inventory in Voronoi polygons, it was possible to evidence a decrease of the total Cs-137 inventory over entire Romanian territory with a factor of about 3 from about 3.6 TBq to less than 1.2 TBq, exceeding in this way the natural decay which suggests that a certain amount of Cs-137 was washed out by precipitation and, at a lower extent, was incorporated into plants. At the same time, by evaluating the maximum contribution of Cs-137 to the population exposure, in 1993 as well as in 2016, the supplementary annual effective dose did not exceed, in the majority of sampling points the value of 0.2 mSv/year.

Automated summary

The total Cs-137 inventory of Chernobyl contamination in Romanian soil samples was estimated in 1993 and 2016. The study found that the Cs-137 inventory varied between 0.4 and 187 kBq/m(2) in 1993, and between 0.2 and 94.2 kBq/m(2) in 2016. The spatial distribution analysis showed a decrease of about 3 times in the Cs-137 inventory over the entire Romanian territory, exceeding the natural decay, suggesting the washout and incorporation into plants. The maximum contribution of Cs-137 to population exposure did not exceed 0.2 mSv/year in both 1993 and 2016.