When this book was first published in 1996, the pollution of the earth's freshwater habitats was, as it is now, a topic of major concern. This synthesis considers the effects of pollutants on aquatic animals via a series of research and review articles that present experimental evidence of sublethal and lethal effects of a range of toxicants at the physiological, cellular and subcellular levels, and that explore techniques for detection of pollution damage. Topics covered include routes of uptake of toxicants; the effect of acute and chronic exposure to toxic metal ions, particularly zinc, copper and aluminium, with emphasis on the mechanisms of toxicity and responses to chronic exposure to sublethal levels; the impact on fish biology of two chemicals of current concern, nitrites and polyaromatic hydrocarbons, which may act as oestrogenic substances or potent mutagens; and in vitro studies of the mechanisms of toxicity at the cellular and subcellular level, including damage of DNA, using cultured fish cells.