Multiple metal interactions with fish gills and organic matter

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Date

2008

Authors

Borgmann, Uwe
Wilkie, Michael
McGeer, J.
Dixon, D. G.
Smith, Scott

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Abstract

Metal loads in contaminated waters are seldom a single metal, but usually a mixture of many metals arising from mining, industrial, or municipal inputs. Using models such as the Biotic Ligand Model (BLM), predictions can be made about the relative strength with which individual metals bind to the gill, how such binding is influenced by water chemistry, and ultimately how such metal binding affects fish health and survival. However, the BLM presently has limited applications for multiple metal mixtures. Our research goals are to: (i) develop and validate a model that predicts how mixtures of Cd, Pb and/or Zn bind to the fish gill; (ii) determine how the complexation of metals by natural organic matter (NOM) influences the fish gill and toxicity when fish are exposed to multi-metal mixtures; and (iii) confirm that observed gill-metal binding is predictive of compromised fish health and survival when fish are exposed to metal mixtures at environmentally relevant concentrations. To simulate the sensitive, NOM-rich waters of the Canadian Shield, our experiments take place in waters of low ionic strength and hardness, to which different concentrations of NOM are added. Our model organism is the rainbow trout (Oncorhynchus mykiss) because we have an in depth understanding of gill function and metal toxicity in this traditional test animal. By comparing the physiological and toxic responses of rainbow trout to environmentally relevant metal mixtures to those of potentially more sensitive fishes (e.g. artic char, brook trout, northern pike) native to Canadian Shield lakes, it will be possible draft realistic and effective guidelines for metal contaminants that are not overly stringent or permissive. This will therefore allow scarce resources to be diverted to other areas of social, economic or environmental importance to Canadians.

Description

Project A2: Principal investigator: M. Wilkie

Keywords

Toxicity, Pb, Cd, Fish gills, Rainbow trout, Zn, Oncorhynchus mykiss, NOM, Biotic Ligand Model

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