|Researchers' finding will supplement the radiation monitoring of rivers and lakes in the Southern Urals.|
Photo Credit: Rodion Narudinov
The method showed its effectiveness in radionuclide-contaminated waters of the South Urals
Otoliths are hearing and equilibrium maintenance organs of fish that do not contain living cells. They can be used as individual dosimeters for radiobiology and radioecology studies. This was discovered by a team of scientists from the Ural Federal University along with their colleagues from the Chelyabinsk State University and the Ural Scientific-Practical Center of Radiation Medicine.
When exposed to ionizing radiation, otolith hydroxyapatite crystals accumulate stable radicals. These radicals are proportional to the absorbed dose. Dosimetry using electron paramagnetic resonance (EPR) detects carbonate ions. As a result, the total radiation accumulated by the fish can be quantified.
The findings of the researchers will supplement the radiation monitoring of rivers and lakes in the Southern Urals, in particular, to detect the impact of radiation from strontium-90 radionuclides in the influence zone of the "Mayak" production association. Scientists concluded that EPR dosimetry in fish otoliths is a promising tool for external or comparable internal exposure.
The researchers tested the method on the otoliths of seven fish from waters in the Chelyabinsk region. The dose on the otoliths is determined to a large extent by strontium-90 in hydroxyapatite. The doses of internal exposure of the fish from the water bodies with different levels of contamination have been estimated in the range from 2 mGy to 200 Gy.
The results of the biological dosimetry studies were published in the journal Radiation and Environmental Biophysics.
Reference: Part of the Chelyabinsk Region was radioactively contaminated as a result of PA "Mayak" operations in the 1950s. Several waters inhabited by ichthyofauna (both natural and specially created for storing radioactive substances) have been contaminated. Several dams were built in the upper reaches of the Techa River, which allowed isolating most of the radionuclides released into the environment. Fish otolith EPR dosimetry is a unique tool to study the effects of radiation upon aquatic organisms.
Published in journal: Radiation and Environmental Biophysics
Source/Credit: Ural Federal University
Reference Number: bio032723_01