Showing papers on "Bioaccumulation published in 1968"

137Cs IN THE PLANTS, PLANKTON AND FISH OF THE FINNISH LAKES AND FACTORS AFFECTING ITS ACCUMULATION

Abstract: Bioaccumulation of 137 Cs in the fresh water organisms was studied during 1964 and 1965 by taking water, plankton, plant, bottom animal, and fish samples from water courses representing widely different limnological types: from eutrophic (rich in nutrients) to oligotrophic (nutrient deficient) lakes. It was shown that the 137 Cs content of all organisms sharply depends on the potassium content of the water. In lakes where this value is less than 1 mg K/l. water, very high values of 137 Cs in fish were reached in 1965—max. 26 nCi/kg fresh weight in perch ( Perca fluviatilis L.). Quantitative estimations show that the four main factors determining the 137 Cs body burdens in the last link of the food-chain, the fish, are: 1 137 Cs content of water—a minor factor as observed differences in the lakes studied have been only about 2- to 3-fold. 2 The limnological type of the lake—this is the main factor effecting 10- to 100-fold differences in the same fish species in different lakes. 3 The quality of food eaten by the fish—a minor factor effecting 2- to 3-fold differences. 4 The biological half-time of 137 Cs in fish—an important factor varying from 20 to 200 days at 15°C in different species and effecting up to 10-fold differences in various species in the same water course. The bulk of the 137 Cs intake takes place through food chains. Direct gill absorption plays a minor role only.