Effect of potassium ferric hexacyanoferrate in feed on 137 Cs uptake and excretion by silver Prussian carp.

The present work documents potassium ferric hexacyanoferrate (KFCF) KFe[Fe(CN) 6 ] containing feed to be an effective and inexpensive countermeasure to reduce the 137 Cs contamination of fish. Laboratory aquarium experiments were performed to investigate the effect of feed containing potassium ferric hexacyanoferrate on 137 Cs uptake and excretion by silver Prussian carp (Carassius gibelio (Bloch, 1782)). After the 120-day period of 137 Cs uptake with feed, reaching equilibrium 137 Cs level in fish, fish in some aquariums received feeds containing either 0.1 % or 1 % KFCF for 180 days in combination with clean feed or with feed containing 137 Cs. These feeds resulted in 3.6 ± 0.7 and 4.4 ± 0.9 times, respectively, lower activity of 137 Cs in fish compared to control fish fed 137 Cs throughout the experiment and receiving feed without KFCF. Following the first 100 days with the KFCF containing feed, the 137 Cs level in fish fed contaminated feed was even lower than in fish receiving clean feed, with a half-life of 137 Cs activity in fish of only T 1/2  = 23-35 days. Using clean feed containing 0 %, 0.1 % and 1 % KFCF for 180 days after the 120-day 137 Cs uptake period, the excretion rates for 137 Cs activity in fish k b ' were (6.4 ± 0.2)⋅10 -3 day -1 , (1.08 ± 0.08)⋅10 -2 day -1 , and (1.3 ± 0.1)⋅10 -2 day -1 , respectively (T 1/2  = 108 ± 3 days, 64 ± 5 days, and 53 ± 4 days). The decrease rates for 137 Cs activity concentrations in fish k b were (8.4 ± 0.3)⋅10 -3 day -1 , (1.3 ± 0.1)⋅10 -2 day -1 , and (1.5 ± 0.1)⋅10 -2 day -1 , respectively (T 1/2  = 83 ± 3 days, 53 ± 4 days, and 46 ± 3 days). Our results demonstrate a statistically significant effect (p < 0.01) of KFCF on the excretion of 137 Cs from silver Prussian carp: T 1/2 decreased from 108 days with clean feeding to 53-64 days when KFCF is added.