Transfer of 90Sr into fish in Finnish lakes

Effect of liming on the behaviour of 90Sr and 137Cs in a lake ecosystem

“…Water samples of 30 l were evaporated and 137 Cs was measured with a high purity Ge detector. 90 Sr was radiochemically separated followed by measurement using liquid scintillation or a low background beta counter (Outola et al, 2009).…”

“…In this paper, average monthly values have been calculated for 137 Cs in fish. 90 Sr was determined from dried samples as described by Outola et al (2009). All results for fish in this paper are given for the edible part of the fish and calculated in relation to fresh weight.…”

“…90 Sr generally remains for a long time in the water phase and is not deposited into sediments as rapidly as 137 Cs. This particular lake, however, is known to have shorter effective half-life for 90 Sr in water (about 6 years) than most other lakes in the region (10 years) according to Outola et al (2009). Thus, a significant amount of 90 Sr had already been deposited in the sediment when the liming was carried out in 1991, five years after the Chernobyl accident and several decades after the nuclear test fallout.…”

“…The standard deviation of the monthly average 137 Cs values derived from several fish size group measurements varied from 3 to 26% on control side and 0.1e45% in the limed part. Fish in Lake Iso Valkjärvi had also been monitored before the liming experiment, and these results have previously been published (Outola et al, 2009;Saxén et al, 2009).…”

“…The transfer of strontium from water into freshwater fish is known to strongly depend on the calcium concentration of the water (Vanderploeg et al, 1975;Smith et al, 2009;Outola et al, 2009). Strontium is an analogue of calcium, and less 90 Sr is accumulated in fish when a higher amount of Ca is present in the water.…”