Specificity of the 137Cs distribution in arable elementary landscape-geochemical system contaminated during the accident at the Chernobyl NPP

Abstract

The main goal of the work was to check whether the regularity in the 137Cs distribution, established in the undisturbed forest elementary landscape-geochemical system (ELGS: i.e., the upper - slope - closing depression), is the same in the meadow system. Cs-137 activity was measured with a step of 1 m by field gamma-spectrometer along three parallel cross-sections, the two of them 185 m long and 15 m away from each other, the third one in between (at the selected measurement points). Obtained results confirmed that despite plowing after the accident 137Cs variation in the arable ELGS demonstrate a pronounced and stable cyclic regularity close to synchronic (r = 0.744, n = 155). 137Cs vertical distribution studied in 44 soil cores down to the depth of 40 cm in 2–5 cm increments (541 specimen in total) confirmed the field plowing after the accident. The radionuclide inventory in the top 10–20 cm layer correlated with the field gamma-spectrometry measurement at the corresponding sampling point. The revealed regular variability of 137Cs distribution in arable conditions allowed us to suggest existence of the universal mechanism responsible for the secondary distribution of elements in ELGS. In our opinion water is the only factor and working body which can produce such an effect. If our hypothesis is correct the obtained results provide valuable information for improving spatial schemes of pollution monitoring and fertilizer application.