Mercury-Sulfur Research

Photo Credit

USDA Forest Service photo by Stephen Sebestyen

Outlet stream at the Marcell Experimental Forest near Grand Rapids, Minnesota, which has one of the longest records of mercury in streamwater in the United States

The Great Lakes region holds one of the greatest amounts of freshwater in the world. In recent years, however, concentrations of two persistent pollutants – mercury and sulfur – have increased. These toxic pollutants are often noted as difficult-to-manage contaminants particularly in freshwater ecosystems. As a result, mercury and sulfur pollution have the potential to affect valuable resources, including freshwater fish and manoomin (wild rice), which is integral to Indigenous food sovereignty and is an important tribal commodity in the Upper Great Lakes region.

Researchers with the Northern Research Station are currently investigating mercury and sulfur pollution from many different research focus areas, broadly including:  

• sulfate bioremediation
• sulfate phytoremediation
• mercury-sulfur cycling 
• economics
• aquatic ecology
• soil science 
• climate change
   

Approach

A subset of current research improves our understanding of mercury-sulfur dynamics and how climate change and mining can influence mercury storage and transport. Some of this research also characterizes the spatial and temporal distribution of mercury in forest soils and determines how mercury influences the health of soil microbe and forest plant communities. 

Other research forecasts the impacts of mercury and sulfur under alternative scenarios and management strategies and model sulfate abatement strategies that minimize costs while meeting water quality standards for health and productivity of manoomin. Researchers are engaging with Tribes to better understand the effects of mercury and sulfur on manoomin and fish and incorporate Tribal needs into future research. 

Researchers are also working to develop strategies to reduce mercury and sulfate levels in the environment. For example, bioremediation and phytoremediation strategies are being developed to reduce sulfate levels. 

Expected Outcomes

• Research on mercury and sulfur is increasing our understanding of mercury and sulfur cycling and consequent effects on ecosystems.
• Implemented research findings will lessen mercury health impacts by removing sulfate before it reaches areas where mercury can bioaccumulate in the food chain.