Accumulation of aluminium by the freshwater crustacean Asellus aquaticus in neutral water

This study examined the accumulation of aluminium (Al), mostly as the insol uble (Al(OH)(3)) species, by the freshwater crustacean Asellus aquaticus at neutral pH. Animals were exposed to a range of Al concentrations (5-356 mu g l(-1)) in three experiments. The first two were of 30 and 50 days durati on, respectively, followed by transfer of the A. aquaticus to water contain ing no Al for 20 days. The third used live and dead animals in order to inv estigate the contribution made by surface adsorption of Al to the total acc umulated. Significant accumulation of Al in the whole tissues occurred by d ay 10 in all animals in the 30- and 50- day experiment. Peak concentrations of Al were measured in animals between days 10 and 20 with high concentrat ion factors ranging from 1.4x10(4) to 5.5x10(3). By day 30, accumulated Al had fallen but was still significantly greater than the control in the 50- day exposure experiment. This 30- day increase followed by decreased accumu lation of Al was repeated over the remaining exposure period (i.e. 30-50 da ys) although rates of uptake and loss and peak tissue levels of Al were hig her. Proportionality between environmental (water) and tissue concentration s of Al occurred at day 20 but not at day 45. Significantly more Al was acc umulated by dead animals than live animals at all Al exposure concentration s. These results suggest that Al is available to the crustacean at neutral pH and that the cuticle may provide an important site of uptake. (C) 1999 E lsevier Science Ltd. All rights reserved.