Heavy metal interactions during accumulation via direct route in fish: a review

Among vertebrates fish are unique as they have two routes of metal acquisition: from water via gills and from the diet via the gut (direct and trophic uptake routes). The direct uptake route is more important because gills are the main target-organ for metal toxicity in fish. The majority of studies into metal toxicity and accumulation in fish are focused on single metals. However, in the natural environment, fish are exposed to multimetal mixtures, toxicity levels of which usually differ from those of single metals as their effect can be additive, higher than additive (synergistic), or sometimes lower than additive (antagonistic). This article deals with the role of heavy metal interactions during accumulation in fish organs/tissues, especially with regard to uptake via direct route of water-borne metals. Although the influence of the presence of particular metals in ambient water on accumulation of other metals in fish has been proved experimentally, such studies are still quite scarce, often fragmental...