Accumulation and long term behaviour of radiocaesium in Norwegian fungi

The accumulation and long term behaviour of radiocaesium in mushrooms were studied at selected sites in Norway. A large variation in transfer factors from soil to mushroom were found with the lowest value of 0.002 m(2)/kg for Leccinum versipelle up to 0.5 m(2)/kg for species of Amanita fulva and Amanita vaginata. Rozites caperata and Cortinarius armillatus were also found to accumulate radiocaesium very efficiently. For the study of long term behaviour of radiocaesium in mushrooms the same species were collected from the same location from 1989 to 1995. Two of four data sets showed a significant decrease in activity levels in the study period with an estimated effective ecological half-life in the range of 1.5-8 years, while a non-significant decrease and no decrease were indicated by the other two.