Search

Copyright of Nuclear Physics & Atomic Energy is the property of National Academy of Sciences of Ukraine, Institute for Nuclear Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To follow up field observations in the Chornobyl Exclusion Zone (ChEZ), a series of controlled model aquarium experiments were conducted to determine the uptake and depuration rates of 137 Cs and 90 Sr in silver Prussian carp (Carassius gibelio) in fresh water, varying in temperature from 5 to 27 °C, with daily feeding rates of 0-1.5 % fish weight day -1 . In the present study, the 137 Cs uptake rates in muscle tissues directly from water, 0.05-0.09 day -1  at temperatures of 5-27 °C, were significantly lower than previously reported for fish fed under natural conditions in contaminated lakes within the ChEZ. The rate of 90 Sr uptake in bone tissues of silver Prussian carp varied from 0.055 day -1  at a water temperature of 5 °C and feeding rates ≤0.15 % fish weight day -1 to 1.5 ± 0.2 day -1  at a temperature of 27 ± 1 °С and at the highest tested feeding rate of 1.5 % day -1 . The rate of decrease of 137 Cs concentration in muscle tissues was k b  = 0.0028 ± 0.0004 day -1 (T 1/2  = 248 ± 35 days) at the lowest water temperature tested (5 °С). At water temperatures between 13 and 26 °С and a feeding rate of 0.15 % day -1 , the rate increased to k b  = 0.0071-0.0092 day -1 (T 1/2  = 75-99 days). The rates of decrease of 90 Sr activity concentration in bone tissues at water temperatures between 22 and 25 °С and a feeding rate of 0.5 % day -1 were k b =0.004-0.0014 day -1 , and the associated biological half-life T 1/2 ranged 50-160 days, respectively. The present work supported conclusions related to the main pathways of 137 Cs and 90 Sr uptake by silver Prussian carp, and demonstrated the usefulness of combining field and laboratory uptake and depuration experiments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Glubokoye Lake situated within the Chernobyl Exclusion Zone is highly contaminated with respect to radioactive caesium and strontium isotopes, which also is reflected in the contaminated fish. To utilize the fish resources in contaminated lakes, the present work presents for the first time the effectiveness of using clean feed to counteract contamination of radionuclides in fish. The study is based on a series of repeated experiments with Prussian carp (Carassius gibelio (Bloch, 1782)) kept in cages in the contaminated Glubokoye Lake during summer 2018-2021. By the addition of clean feed, the activity concentration of 137 Cs in fish muscle tissues was lowered with a factor of 2-5 due to biodilution. Surprisingly, additional clean feed did not lead to further decrease in the uptake of 137 Cs in fish. In contrast to 137 Cs, the addition of clean feed increased the 90 Sr activity concentration in fish by a factor of 2-4 compared to fish fed with naturally occurring feed items. Radioactive strontium accumulated mainly in the fish bones and the muscle tissue level was 2 orders of magnitude lower, similar to the distribution observed for stable Sr. By utilizing a new kinetic model describing the dynamics of strontium isotopes in bone tissues of fish, predictions fitted well with site-specific data, taking growth rates and aging into account. Results showed that clean feeding can be used to counteract high activity concentration of 137 Cs in fish due to biodilution, but cannot counteract bioaccumulation of 90 Sr. Findings highlighted that it is essential to understand underlying factors influencing the uptake pathways for contaminants, as access to clean feed could increase the growth and thereby reduce the body activity concentration of dietary associated radionuclides such as 137 Cs (biodilution), as well as increase the transfer of dissolved compounds such as 90 Sr directly from water to fish., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)