Radionuclides in forest ecosystems
Investigation of the redistribution of radionuclides in forest ecosystems
Tech Area / Field
- ENV-EHS/Environmental Health and Safety/Environment
3 Approved without Funding
National Nuclear Center of the Republic of Kazakstan / Institute of Radiation Safety and Ecology, Kazakstan, Kurchatov
Project summaryExtensive radioactive contamination of territories is directly associated with nuclear tests and radiation accidents on different objects of nuclear industry. At present time environment radioactive contamination as a result of nuclear tests is hardly probable but probability of different nuclear and radiation accidents is high. Due to different radioecological investigations, primary results of environmental impacts are studied rather well. At once, according to the long-term consequences of radiation impact to the environment, there are different assessments which could be checked only at the end of some period on the areas of “historical” radioactive contaminated points. One of the “oldest” is radioactive contamination of Priirtyshie band pine forests as a result of radioactive fallouts from the first nuclear test made on the Semipalatinsk Test Site on the 29th of August, 1949.
Surface nuclear explosions on the Semipalatinsk Test Site caused radioactive contamination not only in the epicentral zones. Radioactive clouds of nuclear explosions were beyond the Site territory, that resulted to radioactive contamination which spread to hundreds kilometers from the test areas creating traces with tens of kilometers width.
According to the investigations made in 2004-2011 on the territory of Priirtyshie band pine forests (Beskaragay area of East-Kazakhstan region) there was found that soil surface contamination with anthropogenic radionuclides 137Cs, 90Sr and 239+240Pu are about hundreds Becquerels per kilogram. To this day, there are forest areas on the traces
of radioactive fallouts which age is more than 60 years. During this period a lot of migration processes and radionuclides accumulation in different ecosystems took place.
The main goal of the proposed project is to assess the current state and distribution of artificial radionuclides via the main components of the pine forest ecosystem in the area of radioactive traces.
To achieve the goal four main objectives have been identified:
1. Analysis of available information and choice of specific areas for research.
2. Investigation of radionuclides distribution in soil and vegetation.
3. Physico-chemical studies of soil and study of radionuclides distribution in the depth of the soil profile.
4. Assessment of the feasibility for using the radioactively contaminated areas for civilian purposes.
The proposed methodology involves a comprehensive, multi-level approach with study of both more simple units, such as "soil-plant" and the migration of radionuclides in the forest floor and in the soil profile, and analysis of the most typical biogeocenoses: coniferous forest, deciduous forest and floodplain forest. To ensure the reliability, the research sites will be put in triplicate considering the level of radioactive contamination in the study area, as well as covering the most characteristic elements of the selected ecosystems. Based on the objectives of the survey at each site we’ll study the quantitative parameters of radionuclides accumulation from the soil (and forest floor) in the above-ground parts of plants and mushrooms, distribution of radionuclides in the soil profile and layers of the forest floor, speciation of radionuclides in the soil. Distribution of radionuclides in inpidual organs of trees, the yearly ring of pine trees over 60 years old, growing during passage of the radioactive cloud, will be investigated.
The results obtained will provide insight on the current radio-ecological situation in the pine forest, including the distribution of artificial radionuclides via main components of the most characteristic ecosystems. The studies in forest areas, whose age exceeds 60 years, will help to give a long-term assessment of developments in radioactive contamination zones of forests due to the accident at Fukushima, and develop a strategy for rehabilitation measures to the degree of potential hazard considering the time factor.
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