ACTIVITY CONCENTRATIONS OF CS-137 IN MOOSE AND THEIR FORAGE PLANTS INMID-SWEDEN

The Cs-137 activity concentrations in moose and their principal fodder plants as well as the botanical composition of the rumen content in m oose were studied in three areas of the county of Vasternorrland in Sw eden. The mean Cs-137 activity concentration in moose muscle samples f rom the three areas with a ground deposition from 20 to 60 kBq m-2 var ied between 540 and 915 Bq kg-1. During the period July to October, th ree plant species - fireweed, birch and bilberry - constitute more tha n 70% of the rumen content. Estimation of the daily Cs-137 intake was performed based on the botanical analysis of rumen content and the Cs- 137 activity concentrations found in samples of fodder plants. A mean F(f) of 0.19 day kg-1 was calculated. A mean aggregated transfer facto r of 0.016 m2 kg-1 was found for the three areas.