Heavy metal contents of fifty one samples of fresh river lamprey from 9 dif
ferent rivers and 5 delta areas of the Gulf of Bothnia were analysed. The m
ean Cd content in the samples was 43 mug/kg and while Hg content was 79 mug
/kg. Only one sample contained 64 mug Pb/kg which is over the detection lim
it of 40 mug/kg Pb. River lampreys caught in the Bothnian Bay, the northern
basin of the Gulf of Bothnia, had significantly higher levels of Cd and Hg
than lampreys caught in the Bothnian Sea, the gulf's southern basin. There
was no significant difference in Cd and Hg content in lampreys caught in r
ivers versus those caught in their respective delta areas.