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Published on: August 29, 2014
Relationship between wetlands and mercury in brook trout
Mark S Castro1, Robert H Hilderbrand, Joe Thompson
1Appalachian Laboratory, University of Maryland Center for Environmental Science, Frostburg, MD 21532, USA. castro@al.umces.edu
Archives of Environmental Contamination and Toxicology
|October 25, 2006
Summary
Wetlands significantly impact mercury levels in brook trout, with higher concentrations found in streams with wetland watersheds. This study highlights the role of wetlands in mercury bioaccumulation in aquatic ecosystems.
Area of Science:
- Environmental Science
- Ecotoxicology
- Aquatic Ecology
Background:
- Mercury is a persistent environmental contaminant.
- Wetlands can act as sources and transformers of mercury.
- Understanding mercury cycling in aquatic ecosystems is crucial for ecological health.
Purpose of the Study:
- To investigate the influence of wetlands on mercury concentrations in brook trout (Salvelinus fontinalis), benthic macroinvertebrates, and stream water.
- To compare mercury levels in streams with and without wetland-dominated watersheds.
Main Methods:
- Collected water, benthic macroinvertebrates, and brook trout from four western Maryland streams under low-flow and high-flow conditions.
- Analyzed total and methylmercury concentrations in collected samples.
- Compared mercury concentrations between streams with and without wetland presence in their watersheds.
Main Results:
- Brook trout from the Little Savage River (7% wetland watershed) exhibited significantly higher total mercury concentrations compared to streams without wetlands.
- Younger brook trout showed varying mercury concentrations, suggesting differences in initial exposure (eggs or fry food).
- Stream water in Little Savage River had higher total and methylmercury, potentially due to in-stream production, while mercury in macroinvertebrates did not significantly differ among streams.
Conclusions:
- Wetlands play a significant role in elevating mercury concentrations in brook trout.
- Methylmercury production in pools and mercury gradients downstream of wetlands may influence aquatic ecosystems.
- The relationship between mercury in water, invertebrates, and fish is complex and warrants further investigation.
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