Effect of aluminium speciation on fish in dilute acidified waters

Acidification of lakes and streams is a serious water quality problem in high elevation granitic ecosystems in the northeastern US 1–3 . An important consequence of acidification is the mobilisation of aluminium from the edaphic to the aquatic environment 3–5 . Elevated levels of aluminium may have serious ramifications for biological communities, particularly fish, inhabiting acidified aquatic systems 5,6 . In this study, water quality data were collected from several acidified lakes and streams in the Adirondack region of New York state. The purpose of this investigation was to characterise aluminium chemistry in these acidified waters and to assess the relative toxicity of soluble aluminium species to fish. Aqueous aluminium speciation was found to be highly variable in Adirondack waters, and its effect on fish was also variable.