Trace metals in the livers of marine mammals from the Welsh coast and the Irish Sea

Metallothioneins pattern during ontogeny of coastal dolphin, Pontoporia blainvillei, from Argentina

“…The marine fetus (in the womb of her mother) presented higher metal and MT levels, mainly in liver, than mean values of the rest of dolphins, even of those of estuarine averages (see Table 2). Similar results, where fetuses have much higher concentrations than those corresponding to their mothers, were previously reported in S. coeruleoalba (Honda et al, 1982), Phocoenoides dalli -Dall's porpoise - (Fujise et al, 1988); Phocoena phocoena -harbour porpoise - (Law et al, 1992) and H. grypus (Teigen et al, 1999). This information is in accordance with the increase transfer of Zn from mother to fetus during pregnancy found in H. grypus (Teigen et al, 1999).…”

“…Zinc is an essential micronutrient for normal growth and development, such as copper (Prohaska and Gybina 2004), which is necessary for the function of more than 300 enzyme systems of mammals, regulating metabolic processes (Tapiero and Tew, 2003). Reports in cetacean (Law et al, 1992, for several species; Wood and Van Vleer, 1996, for Bottlenose dolphins), and pinniped species (Law et al, 1992, for grey seal and common seal -Phoca vitulina; Teigen et al, 1999, grey seal), suggested that concentrations of copper decrease during the first year of life and are followed by the maintenance of fairly constant concentrations throughout an animal's life. Franciscana dolphin presented the same relationship from fetuses to calves, meaning the first year of life, showing an increase in mean values from juveniles to adults in liver but not in kidney.…”

“…Despite this difference in accumulation patterns, they are not reflected in the concentrations and/or patterns of MTs. The behavior of MTs in P. blainvillei could indicate that levels found do not correspond to responses to the presence of Cd in tissues, being that this is a potent inducer of them (Das et al, 2000;Goyer and Clarkson, 2001;Law et al, 1992). Moreover, the environment inhabited by the estuarine group of Franciscana dolphin is influenced by the La Plata River, which is recognized as a high impact environment containing contaminants that can induce the synthesis of MTs.…”

Trace element bioaccumulation in grey seals Halichoerus grypus from the Faroe Islands

“…harp and ringed seals, that are traditionally hunted and which have been extensively studied for trace element and organic compound bioaccumulation (see review by Muir et al 1992), the grey seal has rarely been investigated, and then often using only a few individuals (Morris et al 1989, Frank et al 1992, Law et al 1992, Teigen et al 1999, Dam 2001, Nyman et al 2002. This is proba- bly because most grey seal populations either live in protected areas or are not traditionally hunted.…”

“…Very high Hg concentrations in grey seals from the Irish Sea were related to feeding habits in a very contaminated area, Liverpool Bay, where their prey is enriched in Hg (Law et al 1992). In the Faroe Islands, no such enrichment by industrial contamination exists.…”