Do stream invertebrates accumulate aluminium at low pH conditions?

Acidified surface waters often show elevated aluminium (Al) levels, detrimental to fish and some invertebrates. Whether Al can accumulate in benthic invertebrates, with time and/or along the food chain, is not clear. To test this, benthic invertebrates, representing different functional feeding groups, were collected in spring from streams, with different acidity and Al concentrations. Weight-specific Al content was determined with an AAS. At localities with pH approximate to 4, high Al contents (approximate to 1 mg inorg-Al g(-1) af dw) were found in shredders and/or deposit feeders (Asellus aguaticus, Nemoura sp., and limnephilids), while the predator Isoperla grammatica contained only approximate to 0.3 mg Al g(-1), and the ''filtering predator'' Plectrocnemia conspersa almost no Al. Also at pH approximate to 6 Nemoura sp. and limnephilids showed significantly higher Al contents than did the predators Isoperla grammatica and Rhyacophila rubila, Al concentrations of the animals were often higher at pH 4 than at pH 6. Thus, no evidence of any food chain accumulation (or biomagnification) of Al could be validated. Accordingly, this study gives no support that the high concentrations of Al in fish and birds are due to their feeding on benthic invertebrates at low pH conditions. It was also found that animals that inhabit and/or consume benthic detritus as food contain highest Al levels.