Behavior of the Chernobyl-Derived Radionuclides in Forest Ecosystems and Effects of Radiation

Abstract

This chapter describes the consequences of the Chernobyl accident in forest ecosystems. We focus mainly on forests in the near zone of the accident at the territories of Ukraine and Belarus. Within this area, especially in the Ukrainian part of the 30-km Chernobyl zone, forests were exposed to high doses during the acute phase of the accident resulting in the slight to severe (up to lethal) damages to the ecosystems. Three decades after the accident, Chernobyl forests in the near 10-km zone remain heavily contaminated with long-lived radionuclides such as 137Cs, 90Sr, and isotopes of transuranium elements, which excludes the possibility of their economical utilization in the long term. At the most contaminated places, dose rates to the tree species may reach the level of mGy h−1, that is, exceeding the safe levels for terrestrial ecosystems. We review the data on the radioactive contamination levels in Chernobyl forests, dynamics of radionuclides in the typical tree species at the early and late stages after the deposition, and the effects of acute and chronic radiation to plant species and analyze the contribution of forests to the doses to humans. Many important issues, such as radioactive contamination and effects on animals and others, are out of the scope of this chapter. Although this volume of the book is focused on the consequences of the Chernobyl accident, in some parts of this chapter, we find it necessary to refer to the situation after the Fukushima accident in order to emphasize the generic processes and their mechanisms in the radioactively contaminated forests. Materials of this chapter were partly presented in our recent reviews (Yoschenko et al., J Forest Res 23:3–14, 2018b; Yoschenko et al., Radiocesium dynamics in a Japanese forest ecosystem. Initial stage of contamination after the incident at Fukushima Daiichi Nuclear Power Plant, 2019); here, we present the extended version of the review.