Uptake from water and depuration of 137Cs and 90Sr by silver Prussian carp (Carassius gibelio).

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 137Cs and 90Sr 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 137Cs 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 90Sr 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 137Cs 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 90Sr 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 137Cs and 90Sr uptake by silver Prussian carp, and demonstrated the usefulness of combining field and laboratory uptake and depuration experiments. • The 137Cs uptake rate by fish from water is 5–100 times lower than from contaminated food. • The 137Cs uptake rate by fish from water increased at high water temperatures. • The 90Sr uptake rate by fish from water is much higher than from contaminated food. • The 90Sr uptake rate from water increased with increasing water temperature and feeding rate. • The rates of decrease in 137Cs and 90Sr concentrations increase due to biodilution. [ABSTRACT FROM AUTHOR]