Statistical analysis of 137Cs in freshwater fish

Aim of the study

The object of the study was to obtain material for transfer coefficients of ¹³⁷Cs (CF) in lake waters and in fishes in four small forest lakes in Lammi, in Finland, determined after the Chernobyl accident at STUK. We wanted to find out if there were differences in the transfer of ¹³⁷Cs into fishes in two types of lakes, drainage lakes and seepage lakes.

Implementation

The transfer of ¹³⁷Cs into fishes was analysed with linear regression for 1988-92. Besides various species of fish, various sizes of the fish were taken into account. The relationship between water chemical parameters and CF was also studied between the lake types.

Results

In the drainage lakes the CF decreased during the study period by 9% per year whereas in the seepage lakes the CF increased significantly by 4.3% per year. The transfer of 137Cs into pike was significantly (1.6 times) higher than that into perch. The CF increased on average by 3.4% for each 1-cm increase in the median size of perch. The relationship between the water chemistry and the CF differed between clear-water seepage and brown-water drainage lakes.

Dissemination and exploitation of the results

The study provided information on long-term changes in and recovery from radioactivity in various types of lakes. The results can be utilised in assessments needed in case of some new deposition event.

Collaborators

Martti Rask and Jukka Ruuhijärvi, Evo Game and Fisheries Research Station

Timetable

Results were reported in 2009. The article was published in 2010.

Responsible scientists

Sirpa Heinävaara, Ritva Saxén and Heidi Rand

Page updated 23/06/2010