Excretion of 131I by freshwater catfish (Ictalurus punctatus) and bluegill (Lepomis macrochirus)

Fish in waters to which wastes from nuclear power stations are discharged accumulate radionuclides for a short time during batch discharges and then eliminate them during the longer intervals between discharges. Hence, the elimination rates of radionuclides are of importance in computing radiation doses to humans who eat fish caught in these waters. The excretion rates of 131I in two freshwater fish species were studied. Findings show that 131I is excreted quite rapidly by both species. 131I loss from fish muscle during deep frying was also measured and found to be 20 +- 4%. It is concluded that the practice of simply applying a concentration factor to convert the concentration in water to that in fish, without considering excretion, grossly overestimates the dose to the consumer, and that further studies should be made to identify other nuclides that behave similarly. (author)