RESUMEN
Empirical data on the behavior of radionuclides in aquatic ecosystems are needed for radioecological modeling, which is commonly used for predicting transfer of radionuclides, estimating doses, and assessing possible adverse effects on species and communities. Preliminary studies of radioecological parameters including distribution coefficients and concentration ratios, for (90)Sr and (137)Cs were not in full agreement with the default values used in the ERICA Tool and the RESRAD BIOTA codes. The unique radiation situation in the Techa River, which was contaminated by long-lived radionuclides ((90)Sr and (137)Cs) in the middle of the last century allows improved knowledge about these parameters for river systems. Therefore, the study was focused on the evaluation of radioecological parameters (distribution coefficients and concentration ratios for (90)Sr and (137)Cs) for the Techa River and the Miass River, which is assumed as a comparison waterbody. To achieve the aim the current contamination of biotic and abiotic components of the river ecosystems was studied; distribution coefficients for (90)Sr and (137)Cs were calculated; concentration ratios of (90)Sr and (137)Cs for three fish species (roach, perch and pike), gastropods and filamentous algae were evaluated. Study results were then compared with default values available for use in the well-known computer codes ERICA Tool and RESRAD BIOTA (when site-specific data are not available). We show that the concentration ratios of (137)Cs in whole fish bodies depend on the predominant type of nutrition (carnivores and phytophagous). The results presented here are useful in the context of improving of tools for assessing concentrations of radionuclides in biota, which could rely on a wider range of ecosystem information compared with the process limited the current versions of ERICA and RESRAD codes. Further, the concentration ratios of (90)Sr are species-specific and strongly dependent on Ca(2+) concentration in water. The universal characteristic allows us to combine the data of fish caught in the water with different mineralization by multiplying the concentration of Ca(2+). The concentration ratios for fishes were well-fitted by Generalized Logistic Distribution function (GLD). In conclusion, the GLD can be used for probabilistic modeling of the concentration ratios in freshwater fishes to improve the confidence in the modeling results. This is important in the context of risk assessment and regulatory.
Asunto(s)
Radioisótopos de Cesio/análisis , Ríos/química , Radioisótopos de Estroncio/análisis , Contaminantes Radiactivos del Agua/análisis , Animales , Peces , Gastrópodos , Sedimentos Geológicos/análisis , Monitoreo de Radiación , Federación de Rusia , Algas MarinasRESUMEN
As a result of operation of the Mayak Production Association (Mayak PA), Chelyabinsk Oblast, Russia, an enterprise for production and separation of weapon-grade plutonium in the Soviet Union, ecosystems of a number of water bodies have been radioactively contaminated. The article presents information about the current state of ecosystems of 6 special industrial storage reservoirs of liquid radioactive waste from Mayak PA: reservoirs R-3, R-4, R-9, R-10, R-11 and R-17. At present the excess of the radionuclide content in the water of the studied reservoirs and comparison reservoirs (Shershnyovskoye and Beloyarskoye reservoirs) is 9 orders of magnitude for (90)Sr and (137)Cs, and 6 orders of magnitude for alpha-emitting radionuclides. According to the level of radioactive contamination, the reservoirs of the Mayak PA could be arranged in the ascending order as follows: R-11, R-10, R-4, R-3, R-17 and R-9. In 2007-2012 research of the status of the biocenoses of these reservoirs in terms of phytoplankton, zooplankton, bacterioplankton, zoobenthos, aquatic plants, ichthyofauna, avifauna parameters was performed. The conducted studies revealed decrease in species diversity in reservoirs with the highest levels of radioactive and chemical contamination. This article is an initial descriptive report on the status of the biocenoses of radioactively contaminated reservoirs of the Mayak PA, and is the first article in a series of publications devoted to the studies of the reaction of biocenoses of the fresh-water reservoirs of the Mayak PA to a combination of natural and man-made factors, including chronic radiation exposure.
Asunto(s)
Biota , Agua Dulce/análisis , Sedimentos Geológicos/análisis , Residuos Radiactivos , Radioisótopos/metabolismo , Contaminantes Radiactivos del Agua/metabolismo , Residuos Radiactivos/análisis , Radioisótopos/análisis , Federación de Rusia , Contaminantes Radiactivos del Agua/análisisRESUMEN
The Comet Assay and micronucleus assays have been used to evaluate the condition of the nuclear DNA in erythrocytes of peripheral blood of roach (Rutilus rutilus L.) from water-storage of low-level radioactive waste. The Rutilus rutilus L. from the Shershny reservoir, Chelyabinsk, was used as a control population. Radionuclide maintenance in water, sediments and roach in those reservoirs and Shershny reservoir was defined. The dose rate for Rutilus rutilus L. was calculated using program complex ERICA Assessment Tool 1.0 May 2009. Our investigation has shown that a chronic radiation of population (dose rate - 5.2 mGy/day and 19.5 mGy/day) leads to a significantly higher level of the DNA damage in erythrocytes of peripheral blood and increases the speed of nuclear DNA reparation after irradiation of erythrocytes in vitro. We suppose that it may be a result of the increased quantity of active form of oxygen in cells of the fish in water-storage of low-level radioactive waste.
Asunto(s)
Cyprinidae/genética , Daño del ADN/efectos de la radiación , Reparación del ADN/efectos de la radiación , ADN/sangre , Contaminantes Radiactivos del Agua/efectos adversos , Animales , Ensayo Cometa/métodos , ADN/genética , Pruebas de Micronúcleos , Radioisótopos/análisis , Ríos , Federación de RusiaRESUMEN
In summer 2009, the level of pathology of erythrocytes was assessed in the peripheral blood of roach (Rutilus rutilus L.) from the reservoirs for water-storage of low level radioactive waste of PA "Mayak". Roach from the Shershny reservoir and the Buffer reservoir (Chelyabinsk region) was used as a control. Radionuclide maintenance in water, sediment, and roach was determined and dose rates for the roach were calculated using the software package ERICA Assessment Tool 1.0 May 2009. It is revealed that chronic radiation exposure with the dose rates in the range from 0.8 up to 19 mGy/d leads to a twofold increase in the frequency of erythrocytes with micronuclei in peripheral blood, dose-dependent increase in the frequency of red blood cells with the nuclear pyknosis and causes no significant increase in the level oferythrocyte amitosis. It is suggested that the frequency rate of apoptosis in peripheral blood erythrocytes of the fish could be used in the biological monitoring of contaminated aquatic ecosystems.