Artificial radionuclides in fish fauna of the Yenisei River in the vicinity of the Mining-and-Chemical Combine (Siberia, Russia)

Institute of Biophysics SB RAS, Akademgorodok, 660036 Krasnoyarsk, Russia,

e-mail: t_zotina@ibp.ru

Abstract

Activities of radionuclides were measured in five species of fish (grayling, dace, crucian carp, pike, cod) sampled in the Yenisei River (Siberia, Russia) in the vicinity of the Mining-and-Chemical Combine (ROSATOM) from 2007 to 2010, with a gamma-spectrometer (Canberra, USA). The analyses of samples of organs and tissues of fish species revealed artificial (⁴⁶Sc, ⁵¹Cr, ⁵⁴Mn, ^58,60Co, ⁵⁹Fe, ⁶⁵Zn, ⁸⁵Sr, ⁹⁹Mo, ^103,106Ru, ¹³⁷Cs, ^141,144Ce) and natural (⁷Be, ⁴⁰K) radionuclides in fish organs and tissues, including edible ones. The major percent (up to 80%) of ¹³⁷Cs and ⁴⁰K activity occurred in muscles of fish species, which also contained considerable percentages of ⁶⁰Co (up to 70%) and ⁶⁵Zn (up to 20%). Seasonal changes in the intake of artificial radionuclides by zoobenthos-feeding fish species (grayling and dace) were recorded and they were followed by an activity concentration increase in internal organs. The dramatic increase in radionuclide intake by grayling coincided with the change of diet source. Hence, the feeding behavior of fish can change the fluxes of artificial radionuclides in the Yenisei River. The most effective diet transfer of a radionuclide from gammarus to grayling (muscles and total body) was recorded for ⁴⁰K (1.3) and much less effective for artificial nuclides.