Aquatic Toxicology and Ecology
Fate and Effects of Metals: Regulatory and Risk Assessment Perspective
Assessment of Amphibian Risks in Wetlands Containing Elevated Metal Concentrations
R.N. Hull, C.E. Moore, L.J. Marshall, N. Ackeray, Intrinsik Environmental Sciences Inc.
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Amphibians are an important component of a wetland ecosystem. Typically, evaluation of water quality is completed by comparing concentrations in water collected from a wetland to Water Quality Guidelines for the Protection of Freshwater Aquatic Life (WQGs). However, only some WQGs for metals and metalloids (e.g., Canadian WQG for cadmium) were developed with the inclusion of amphibian toxicity data. Whether or not amphibian data were included, it is unclear how protective WQGs are of amphibian populations in wetland environments. The current study compared metal concentrations in water collected from eight wetlands potentially influenced by industrial emissions, and four reference wetlands, to WQGs and amphibian toxicity data collated from the literature. This analysis was put into perspective using amphibian diversity and abundance data for these same wetlands, to arrive at an overall conclusion of potential risks to amphibian populations in wetlands near the facility. The analysis showed that, although concentrations in water exceeded WQGs for several metals and metalloids, concentrations generally were below amphibian toxicity effect levels, and amphibian diversity and abundance were not negatively impacted. This may be due to organic enrichment in the wetlands.