Phytoremediation of Soils Contaminated by Uranium
Development of Phytoremediation Technology to Remediate Soils Contaminated with Anthropogenic Uranium in Kyrgyzstan
Tech Area / Field
- CHE-RAD/Photo and Radiation Chemistry/Chemistry
- ENV-RWT/Radioactive Waste Treatment/Environment
3 Approved without Funding
National Academy of Sciences of Kyrgyzstan / Institute of Chemistry and Chemical Technology, Kyrgyzstan, Bishkek
- JSC Biochimmash, Russia, Moscow\nDokuchaev Soil Science Institute, Russia, Moscow
- University of Saskatchewan, Canada, SK, Saskatoon
Project summaryThe objective of the project is to develop phytoremediation technology to bio-remediate soils contaminated with radioactive and heavy metals using native plant species and their associated rhizosphere microbial communities. Urgency of such studies for Kyrgyz Republic is obvious in connection with the contamination of biocenosis in consequence of the discharges of radioactive elements resulting from uranium mining industry in the environment and, as a result, more than 80 contaminated sites are accounted for in the Republic. These radioactive contaminated sites are located mainly in the districts of Ak-Tyuz, Kadzhi-Say and Maily-Suu. Although uranium processing is no longer practiced in Kyrgyzstan, a large number of open landfills and uranium ore storages still remain abandoned at the vicinity of these settlements. These neglected sites have enormous problems associated with soil erosion and known as “technogenic deserts”. The upper soil horizons are deprived of humus and vegetation, which favor the formation of low-buffer landscapes in the zones of maximum contamination. As a result, most of these areas are not re-cultivated and remain in critical environmental conditions. The Kyrgyz Republic is located in an active seismic zone, thus status quo poses imminent threats for natural disasters including contamination of large territories due to the possibility of earthquakes, landslides and mud-torrents in these areas.
Currently, phytoremediation technologies are not used in Kyrgyzstan, but the technology has the potential to be profitable due to the inherent climatic characteristics of the Republic. The Kyrgyz climate allows for a long vegetative period of plants and goes from March till November, thus favoring optimal conditions for soil microflora development. In our project, phytoremediation technology will be used in an environmentally friendly manner in situ i.e., on places conferring ecological safety for plants and living organisms, especially where costs of project implementation and its maintenance are reasonably low.
A key point during the development of phytoremediation technology includes the identification of a suitable plant species that is adapted and capable to grow in heavily polluted sites. The processes of xenobiotic degradation in soil can be encouraged not only by using specially selected plants, but also by the promotion of conditions leading to intensive growth and by increasing metabolic activity of rhizosphere microbiocenosis. This can be achieved by introducing microbiological agents, created from perspective strains of rhizosphere microorganisms isolated from adapted and resistant plants, and/or from humic substances with high growth-stimulating activity. The project is devoted to development of the scientifically-proved effective biotechnology to remediate in situ of environment.
In order to achieve our goals, the following tasks need to be solved:
- To assess the current conditions of polluted soils in terms of quantitative and qualitative indicators of heavy and radioactive metals, humus, fermentative activity, as well as functional pools of soil microorganisms by using author method “Reality Bios”.
- To create a database of plants with potential for phytoremediation using the following criteria: Plant ability to grow on anthropogenic-polluted soils i.e., tolerance to toxic pollutants, Phytotoxicity ability (seed emergence in pollution conditions); and, Quality of root exudates.
- To screen, identify, test and maintain stable and technological microbial strains that exhibit stimulatory plant growth characteristics from soils and/or rhizosphere of potential plants.
- To evaluate stimulating effect of humic agents with respect to the plants in the presence of toxicants (heavy and radioactive metals) using bio-testing.
- To evaluate the potential of selected plants to uptake contaminating substances (heavy metals) using bio-testing. Study of mechanisms for uptake heavy metals by plants.
- To develop biotechnology for obtaining symbiotic microbial agents based on beneficial rhizosphere microorganisms and humic substances.
- To conduct remediation studies in lab (with hydroponic culture, using germs, and greenhouse experiments) and field experiments to prove technology regimes.
The research will be conducted at cooperation of V.V.Dokuchaev Soil Sciences Institute and Institute of Applied Biochemistry and Machine-Building OJSC “Biochimmash”. The collective experience of project participants consists of microbiologists, biochemists, toxicologists, chemists, ecologists and biotechnologists. They all have extensive work experience on the establishment of ecologically safe technologies for remediation of xenobiotic polluted soils e.g., ISTC projects #KR-964 and #KR-1316.
Most of project participants from ICCT and Biochimmash are former biological weapon scientists. The project fulfills the premises and purposes of the ISTC. Additionally, the project will also allow redirecting Kyrgyz and Russian scientists to work on development of technologies designed for environmental protection and to integrate them more effectively into the international scientific community.
The proposed scientific development of phytoremediation of soils by using symbiotic microbial agents based on beneficial rhizosphere microorganisms and humic substances has no world analogs. The development of phytoremediation technology proposed will allow returning spoiled and polluted areas into a safe agricultural use. Benefits from this technology include: The elimination of centers of pollution, Improvement of the soil environment, Drastically lower health risk of human populations living in the vicinity of contaminated areas.