Comparison of heavy metals, parasites and histopathology in sculpins (Myoxocephalus spp.) from two sites at a lead-zinc mine in North East Greenland

Highlights: • Mestersvig mine Pb-Zn mine in East Greenland has led to significant metal pollution. • Gill and liver morphology of fourhorn and shorthorn sculpins was evaluated as bio-indicators. • Significant pathologies were found and were related to metal concentrations. • Sculpin pathology may be suitable health indicators mining activity effects. • These should be enrolled in EIAs of raw material industrialisation in the Arctic. The former lead-zinc mine at Mestersvig, Greenland, continues to contaminate the surrounding environment despite its operations ceasing over 50 years ago. Elevated concentrations of heavy metals are found in water, sediment and biota in the terrestrial, freshwater and marine environments. To shed light on the present contamination and its potential effects on local fish we investigated gill and liver histology of sculpins (Myoxocephalus spp.) around the former mining area. Two species of sculpins were caught; shorthorn sculpins (M. scorpius; n = 16) and fourhorn sculpins (M. quadricornis; n = 17) at a contaminated site, Nyhavn, and shorthorn sculpins (M. scorpius; n = 25) at the reference site. In a previous study we found histopathological changes in the tissues of the sculpins, and we suspected this to be related to elevated heavy metal tissue concentrations. Concentrations of Fe, Hg, Mn, Pb, Se and Zn were significantly higher in sculpins at Nyhavn compared to the reference site. Reference NOED and LOEC thresholds for biochemistry, tissue lesions, growth, survival and reproduction for hepatic Hg, As, Cd and Pb from the ERED database were exceeded in both sculpin species. Histopathological investigations of the sculpins gills revealed significant increases in the prevalence of hyperplastic epithelium, inflammation, intensity of neutral and total mucus cells and chloride cells along with an increased infection of colonial Peritricha. At the contaminated Nyhavn site, fourhorn sculpins had a significantly higher prevalence of chondroplastic tissue and intensity of neutral, mixed and total mucus cells in the gills compared to the shorthorn sculpins. The data indicate that both sculpin species could be useful indicator species for environmental monitoring of metal pollution in Arctic areas. However, confounding effects of gender and species should be investigated further. Effects on other biomarkers as well as baseline measurements should be included in future environmental monitoring efforts around mining activities in Greenland.