Distribution of radionuclides in moss-lichen cover and needles on the same grounds of landscape-climatic zones of Siberia

Publication date: March 2019

Source: Journal of Environmental Radioactivity, Volume 198

Author(s): I.N. Malikova, V.D. Strakhovenko, B.L. Shcherbov

Abstract

The radiation status of the landscape and climatic zones of Siberia at the turn of the 20th and 21st centuries is characterized using bioindicators/biomonitors: lichens, mosses, and needles, according to the results obtained at the sites of their joint growth. The maximal activity of ¹³⁷Cs in these components is observed in the forest-tundra landscaped zone, polluted during the period of nuclear tests from the nuclear test site "Novaya Zemlya" and also due to slow migration of these elements to the soil under the arctic conditions. In the southern territories the specific activity of radiocesium in the moss-lichen cover and needles of conifers corresponds to the regional background, in the forest-tundra zone it sometimes exceeds it, but in general does not pose a threat to human health.

Determined differences in the contents of radioactive elements in lichens and mosses that grow together on sites in different landscape zones of Siberia statistically not significant within one or two standard deviations, and recorded only in the range of 3ϭ at the level of significance 0.05. Specificity of radionuclide distribution in lichens, mosses and needles (differences for epigeals and epiphytic lichens; different species selected at one site, annual and perennial needles, etc.) made it possible to identify the causes of variations in their activities in different zones, along with landscape features of these zones. In the needles of conifers potassium concentration exceeds the content in lichens, at lower levels of thorium and ¹³⁷Cs.

The contents of uranium and thorium in the studied components in all landscape-climatic zones correspond to the natural ones, except for the single local territories, because of the possible anthropogenic influence.

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