Concentrations of trace metals in the livers of marine mammals (seals, porpoises and dolphins) from waters around the British Isles

Samples of liver from sixty-nine marine mammals of eight species found on or near coasts around the British Isles in 1988-1989 have been analysed for a range of trace metals (Cr, Ni, Cu, Zn, Cd, Hg, and Pb). The animals sampled comprised forty-two seals, twenty porpoises and seven dolphins, collected from the North and Irish Seas, and from the English Channel. The range of concentrations for each metal were, in μg g^-1 wet wt: Cr, <0.4-1.0; Cu, 3.8-160; Zn, 25-140; Cd, <0.06-11; Hg, 0.26-430; Pb, <0.6-4.3; all values for Ni were below the limits of detection, as were the majority for Cr and Pb. An apparent 'hot-spot' for concentrations of Hg and Pb in the Irish Sea has been identified, with elevated concentrations of both elements in animals from the vicinity of Liverpool Bay, and of Hg in a small number of seals from the eastern coast of Northern Ireland. Only in the case of Hg, and then only in a few individuals, are the concentrations high enough to give cause for concern.