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TA3 Metals in the Environment: Aquatic Biological Perspectives
() Validation of the Biotic Ligand Model for copper in estuarine and marine crustaceans.
Barcarolli, I1, Martins, S1, Pedroso, M1, Pinho, G1, Bianchini, A1, 1 Fundação Universidade Federal do Rio Grande, Rio Grande, RS, Brazil
ABSTRACT- The protective effects of various water chemistry parameters on acute copper toxicity have been modeled in the Biotic Ligand Model (BLM). This model simultaneously accounts for the speciation and complexation of dissolved metal and competitive binding of metal and other cations at the site of action, the gill. Despite the important differences in the concentrations of possible copper ligands (Cl-, SO42-, NOM, S2O32-, sulfide, Br-, B(OH)4-) or competitors (Na+, Mg2+, Ca2+, K+, Sr2+) in freshwater versus brackish or seawater, attempts to validate the BLM model in estuarine/marine animals are scarce. Thus, we evaluated the ability of the current BLM version to predict acute copper toxicity in a wide range of salinity in three different groups of estuarine and marine crustaceans, in either the absence or the presence of food in the water. Copepods (Acartia tonsa), isopods (Excirolana armata) and crabs (Chasmagnathus granulata) were acclimated to different salinities. Groups of 10 acclimated animals were exposed to different concentrations of copper (CuCl2), for 48 h (copepods and isopods) or 96 h (crabs) using a standard static-renewal system in the absence or the presence of food (copepods = algae; isopods = chopped fish; crabs = seagrass). Tests were run in duplicate with direct measurements of the different water chemistry parameters considered in the current BLM. Our results show a markedly higher sensitivity to copper in non-gill breathing (copepods) than in gill breathing (isopods and crabs) crustaceans. They also indicate that acute copper toxicity is highly influenced by both salinity and the presence of food in water, for all species tested. Furthermore, we found a very good capacity of the current version of the BLM to predict our acute copper toxicity results across a range of salinities from freshwater to seawater. (Supported by International Copper Association).
Key words: copper, biotic ligand model, crustaceans, seawater
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