The distribution of dissolved aluminum in Atlantic salmon (Salmo salar) rivers of Atlantic Canada and its potential effect on aquatic populations

Abstract

Studies from the 1980s concluded that aluminum (Al) was not a significant contributor to Atlantic salmon ( Salmo salar ) toxicity in Nova Scotia, located on Canada’s Atlantic coast, because of the presence of dissolved organic matter that rendered ionic Al (Ali) biologically inaccessible. Since this earlier work, new interpretations of Alieffects, as well as improved techniques for its measurement, have been developed. However, no new data interpretation has been done to see if the conclusions reached in earlier work for Atlantic Canada were still valid. We sampled 97 salmon rivers from the provinces of New Brunswick (NB), Nova Scotia (NS), and the island of Newfoundland (NF) to determine total and Aliconcentrations to see if results exceeded newer toxicity standards established by the European Inland Fisheries Advisory Commission. We found that southwestern NS, the region with the greatest loss of salmon populations, has seven rivers where autumn Alivalues exceed values identified as toxic to aquatic life. A further three rivers exceed guidelines in NF. Our work shows that the sources of toxicity for salmon and other aquatic species in acidified environments are more complex than previously thought.