SOIL EROSION AND RADIOACTIVITY: THE CHERNOBYL EXPERIENCE

The results are presented of experimental studies conducted on two runoff plots located within the Chernobyl Exclusion Zone. Studied was the water-erosion transfer of ¹³⁷Cs and ⁹⁰Sr by both solid and liquid runoff, as a result of both natural processes and intense artificial rainfall simulations that took place throughout one year.

It has been established that, despite the differences in soil types, slope angles and exposure, as well as in the density of radioactive contamination, erosion-caused transfer of radionuclides is highly insignificant, amounting to some hundredth parts of one percent of their reserves on the plot under natural conditions, and to single percents of the same under artificial rainfall simulations that exceeded 3-5 times by their intensity the heaviest storms occurring here. Radioactive cesium migrates mostly with the solid runoff, while radioactive strontium – mostly with liquid runoff.

Taking into consideration the predominantly flat topography of the exclusion zone, as well as its being mostly covered with turf and forest, the real-life numbers characterizing the transfer of radionuclides into the river network would be much lower than obtained at the experimental plots. The dosage of radiation absorbed by the soils was calculated. It was established that the real absorbed doses are by 5-6 orders of magnitude lower than would be needed to alter those physical/mechanical properties of the soils that determine their susceptibility to erosion.