Possibility of growing ecologically sound biomass in Cs-contaminated soils by polymer compositions

As of May 2013, 30 countries worldwide are operating 436 nuclear reactors for electricity generation and 70 new nuclear plants are under construction in 14 countries. Nuclear power plants provided 12.3 % of the world's electricity production in 2011. Nuclear energy is a cost-effective and reliable energy source, producing affordable, on-demand electricity at an 89 % production rate. Nuclear energy also supports clean air, land, water and wildlife, providing the majority of our nation's emission-free energy. Safely serving as a workhorse of the country's electric grid for more than four decades, nuclear energy is essential to our everyday lives. But the other hand even normalized emissions of atomic industry entities and nuclear power engineering facilities gradually, in the course of time, cumulate in soils and then enter the agricultural production chain. Ecosystems throughout the world have been contaminated with radionuclides (RN) by aboveground nuclear testing, nuclear reactor accidents and nuclear power generation. Soil contaminated with RN pose a long-term radiation hazard to human health through exposure mainly via the food chain. Therefore, constant supervision and remediation of contaminated soils is an urgent need for any country throughout the world. Radioisotopes characteristic of nuclear fission are released into the environment and become more concentrated as they move up the food chain often becoming human health hazards. Amongst the man-made RN 137Cs exerts long-term after-effects of radionuclide caused contamination: for 137Cs the half-life is 30.1 years. A large portion of some RN, including 137Cs, would remain in the root-zone soil for many years after their deposition. This means that a radioactive deposition onto soil can lead to a root uptake lasting for many consecutive years. The ability to predict the consequences of an accidental release of RN relies mainly on the level of understanding of the mechanisms involved in radionuclide interactions with different components of agricultural and natural ecosystems. The research team has developed new means for growing ecologically sound biomass for food in RN-contaminated soils through regulation of biological migration of anthropogenic RN (particularly 137Cs) by adding polymer compositions to the ecosystems 'water- soil- plant' and 'water- nutrient solution-plant'. The composition on the base of inorganic filler, in this case bentonite, has high level of absorption of radioactive cesium (Water purification coefficient = 2.71 for 137Cs and 2.62 - for 134Cs) and was selected for testing in soil and hydroponic conditions. It has been found out that application of this polymer in the root-inhabited media, in comparison to the control variant (without applying polymer), promoted the decrease of 137Cs content in Japanese basil (Shi-so, Perilla frutescens v. crispa) leaves 5.7 and 2.1 times under hydroponic conditions and field experiments, consequently. The field tests have proved that polymer composition can regulate cesium transfer in 'water-soil-plant' and 'water- nutrient solution-plant' systems. The research results can be successfully used for overcoming and eliminating of the catastrophic consequences of Fukushima-1 NPP nuclear accident. The research has been funded under A-2072 ISTC. (authors)