Uptake from water and depuration of 137 Cs and 90 Sr 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 137 Cs and 90 Sr in silver Prussian carp ( Carassius gibelio) ) in fresh water, varying in temperature from 5 to 27 degrees 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 day1 1 at temperatures of 5-27 degrees 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 day1 1 at a water temperature of 5 degrees C and feeding rates <= 0.15 % fish weight day1 1 to 1.5 f 0.2 day1 1 at a temperature of 27 f 1 degrees & Scy; and at the highest tested feeding rate of 1.5 % day 1 . The rate of decrease of 137 Cs concentration in muscle tissues was kb b = 0.0028 f 0.0004 day 1 1 (T 1/2 = 248 f 35 days) at the lowest water temperature tested (5 degrees & Scy; ). At water temperatures between 13 and 26 degrees & Scy; and a feeding rate of 0.15 % day 1 , the rate increased to kb b = 0.0071-0.0092 day 1 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 degrees & Scy; & Scy; and a feeding rate of 0.5 % day1 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.