Effects of aluminium on different forms of phosphorus and freshwater plankton

Experiments investigating the effects of 10 mg.l‐1 aluminium on different forms of phosphorus and on planktonic community present in lake water showed that aluminium addition rapidly precipitated particulate phosphorus and orthophosphate, but had little effect on hydrolisable forms. Phytoplankton was virtually totally precipitated by aluminium flocculation. Cyclops and Daphnia species were more sensitive than Diaptomus to 100 μg.l‐1 aluminium. Data suggest that Zooplankton mortality can be attributed to the toxic effect of the decrease in pH value induced by aluminium.