DNA oxidative damage and vitamin A reduction in fish from a large lake system in Labrador, Newfoundland, contaminated with iron-ore mine tailings

Reactive oxygen species are believed to play an important role in a variety of pathological conditions and considerable speculation has arisen on whether contaminants might play a role in human and animal health through enhancement of various oxidative processes. Although epidemiological information is limited with respect to observations on either humans or wildlife, evidence has been produced for pollutant-mediated DNA oxidative damage in fish in Puget Sound. We now provide evidence for a level of DNA oxidative damage in trout from a large lake system in Labrador, Newfoundland, receiving effluents from iron-ore mines. Studies were carried out by GC-MS with selected ion monitoring and higher levels of the ring opening products, Fapyguanine and Fapyadenine, were detected in the DNA of liver tissues of fish from the lake receiving the highest load of iron-ore tailings. Notably, fish in this lake also had markedly reduced levels of vitamin A. The study provides a second case history for oxidative damage in fish in the environment and indicates the potential importance of transition heavy metals such as iron in producing damage. It also lends support to the evolving viewpoint that many water quality guidelines should be revisited in terms of new ecotoxicological criteria.