Seasonal variation in the content of 137Cs in different objects of forest ecosystems in Chernobyl exclusion zone

Abstract

Seasonal changes in the content of 137Cs in the soil and vegetation of forest ecosystems in the territory of the Chernobyl exclusion zone have been studied. Samples were selected during 2013 from January till March one time per month, and from April till December – one time per two weeks. The study subjects were forest litter and the upper layers of the humus-eluvial horizon of soils, one- and two-year-old needles and branches of P. sylvestris. The 137Cs content was measured by gamma spectrometry methods. Dependences of changes in 137Cs concentrations from the season of the year in the soils were not revealed. The leaping increase in the content of 137Cs in the soil layers throughout the year is likely to be related to changes in the quantity of pedobiota and the intensity of the processes of its vital activity. In the needles and branches of P. sylvestris the maximum values of 137Cs concentration are noted in the summer. Minimum values of 137Cs content in the studied organs of P. sylvestris are characteristic for the autumn-winter period. As a result of the studies, linear relationship was found between seasonal changes in 137Cs concentration in needles and branches of P. sylvestris in testing areas with different levels of contamination. Changes of the 137Cs content in the studied organs of P. sylvestris, which coincide in time at different testing areas, indicate common regularities of 137Cs redistribution at the soil-vegetation chain in forest ecosystems throughout the year.

Keywords

• exclusion zone of ChNPP
• forest ecosystems
• seasonal changes
• content of 137Cs.