A Field Experiment To Determine the Relative Importance of Prey and Water as Sources of As, Cd, Co, Cu, Pb, and Zn for the Aquatic Invertebrate Sialis velata

• Published in: Environmental science & technology 2006-02, Vol.40 (3), p.873-879
• Main Authors: Croisetière, Louis, Hare, Landis, Tessier, André
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Animals; Applied ecology; Biological and medical sciences; Chironomus riparius; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on protozoa and invertebrates; Environmental science; Field study; Food Chain; Food chains; Food contamination & poisoning; Fundamental and applied biological sciences. Psychology; Industry; Insecta - chemistry; Insects; Invertebrata; Larva; Metals, Heavy - pharmacokinetics; Predatory Behavior; Sialis velata; Trace elements; Water - chemistry; Water Pollutants - pharmacokinetics; Water pollution
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es0516209

We measured the relative importance of water and food as sources of the trace elements As, Cd, Co, Cu, Pb, and Zn for larvae of the benthic insect Sialis velata. To achieve this end, we first exposed its prey, the midge Chironomus riparius, to trace elements in a contaminated lake located near a nonferrous metal smelter in northwestern Québec. Concentrations of five of the six trace elements reached a steady state in prey within one week. When predators were exposed to these contaminated prey, their trace element concentrations increased markedly for all of the trace elements studied. In contrast, exposure of S. velata to contaminated lake water led to no significant increase in their concentrations of five of the six trace elements ([Pb] increased only slightly). Additional treatments in which the predator was exposed to these trace elements in both food and water or in a combination of food and water and sediment did not lead to further increases in its contaminant concentrations beyond those measured in the food-only treatment. We conclude that food (prey) is the almost exclusive source of As, Cd, Co, Cu, and Zn for S. velata and that it is the source of 94% of its Pb. Model curves for trace element accumulation over time by the predator fit our measured data well, and trace element concentrations in food alone are sufficient to model the exchange of these contaminants in this insect.