Radioresistance of aboriginal earthworms of Absheron peninsula in radioactive model systems

Full text : Soil animals are the most suitable biological indicators of radioactive pollution because they are parts of nutritional chains and webs, occur in relatively high numbers and can be collected during most parts of the year. The use of earthworms in the soils from Ramana (Baku) iodine plant area of Absheron peninsula, which is rich with radionuclide and in the soil mixed with RaCl2 and UO2SO4 salt solutions in different concentrations, for resistance to ionizing radiation in soil is reviewed. Effect of radionuclides on vital functions of earthworms and determination of radionuclides (before and after experiments) in contaminated soils by γ-spectrometer were carried out in laboratory condition during a month. Regarding to γ-spectrometric results there were determined that earthworms had absorbed most of radioactive elements and allocated them as coprogenous substances on the upper layer of soil. In Ramana soils mostly the 238U radionuclides were highly accumulated in gut cells of the earthworms. By the influence of radioactive elements it was shown that the earthworms from Ramana iodine plant territory variants had proved particularly sensitive to an increased Ra-radiation background and to iodine factor. It was interestingly established the proportional dependence between rising level of accumulation in earthworms body and in their coprolites and increasing of radioactive salts containing in the soils treated by UO2SO4 and RaCl2 solutions. Thus there is different level of radioresistance for earthworms and they are among the best bioindicators of polluted soils. There was an obvious perspective of using of earthworms as bioremediators in polluted soil with radionuclides in future as well.