Heavy metal pollution in Antarctica: a molecular ecotoxicological approachto exposure assessment

Trematomus bernacchii sampled from two sites at Ross Island, Antarctica, we re assessed for condition (gonadal and hepatic somatic indices and conditio n factor), pathological state (liver and gill histology), hepatic metal (Zn , Cu, Cd and Ni) concentrations, and metallothionein induction by quantitat ive competitive (qc) RT-PCR. Fish from a polluted site (Winter Quarters Bay ) had pathological anomalies including necrosis and periductal inflammation in their livers, and X-cell disease, epithelial hyperplasia, lamellar fusi on and aneurysms in their gills. Such anomalies were less common in fish fr om a relatively pristine site (Backdoor Bay, Cape Royds). Fish from both si tes had similar liver concentrations of Zn, Cu and Cd and qcRT-PCR revealed similar levels of hepatic metallothionein mRNA. Ni in the livers of fish f rom Winter Quarters Bay were higher than those in fish from Backdoor Bay, b ut the differences were not great enough to affect hepatic metallothionein mRNA significantly. Despite the polluted state of Winter Quarters Bay water s, it seems that the heavy metals present may have only limited impact on t he health status of fish collected from this locality. This may reflect a l ow bioavailability of the heavy metals in Ross Island marine sediments and suggests that other factors, such as relatively high levels of organic poll utants (PAHs, PCBs) or pathogens from the nearby sewage outlet, may play a more significant role in the aetiology of pathological conditions in fish f rom Winter Quarters Bay. (C) 2000 The Fisheries Society of the British Isle s.