Environmental Health - Toxic Substances Hydrology Program

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Mercury in Aquatic Ecosystems

Areal photograph of lakes in Voyageurs National Park, Minnesota.
Voyageurs National Park (VNP), a pristine setting with abundant lakes, wetlands, and streams situated on granitic bedrock, is located near northern Minnesota's border with Canada. Long-term studies at VNP have revealed trends in mercury concentration in precipitation, surface water, and fish. Photo credit: David P. Krabbenhoft, USGS

Mercury occurs naturally in the environment and cycles among the atmosphere, water, and sediments. Human activities such as coal burning power plants and waste incineration increase the amount of mercury cycling in the environment. Since the industrial revolution, anthropogenic mercury emissions have increased, resulting in corresponding increases in mercury levels in terrestrial and aquatic ecosystems.

Mercury that is released into the atmosphere can be transported long distances and deposited in aquatic ecosystems, where it can potentially be methylated to methylmercury. Methylmercury, the most toxic form, bioaccumulates in organisms and is transferred through the food chain to other animals and humans primarily through fish consumption.

Power plant smoke stacks
Burning coal for energy production contributes large amounts of mercury to the atmosphere. Photo Credit: Phillip J. Redman, USGS.

This investigation is providing the science to understand the real versus perceived risks of mercury contamination on humans and other organisms with the intent to minimize exposure and adverse effects. The investigation is working toward achieving this goal by:

  1. providing a national-to-global scale scientific perspective of environmental mercury contamination;
  2. providing scientific information to support resource managers and decision makers; and
  3. identifying and fill science gaps through research that provides a complete understanding of mercury cycling and effects from sources to receptor organisms.


Looking up at at power plant smoke stack

North American and European Atmospheric Mercury Declines Explained by Local and Regional Emission Reductions

Recent findings from a consortium of university, State, and USGS scientists indicate that declining atmospheric concentrations of mercury (Hg) can be explained by the phaseout of mercury in many commercial products and by reduced emissions from utilities over the past two decades. ...

A map that shows mercury source attribution in the Great Lakes

New Tool to Track Sources and Exposure Pathways of Mercury in the Environment — Application for Predatory Fish in the Great Lakes

The US Geological Survey (USGS) and collaborators at the University of Wisconsin-Madison have developed a new tool for attributing (fingerprinting) mercury sources to the Great Lakes. This new fingerprinting tool helps resource managers understand which mitigation strategies will be most effective for reducing mercury loading and exposure to fish and wildlife. ...

Power plant smoke stacks

Comprehensive Assessment of Mercury in Streams Explains Major Sources, Cycling, and Effects

A new USGS report, Mercury in the Nation's Streams—Levels, Trends, and Implications, presents a comprehensive assessment of mercury contamination in streams across the United States. It highlights the importance of environmental processes, monitoring, and control strategies for understanding and reducing stream mercury levels. ...

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Access to all publications from this investigation.

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Scientists prepare to lower a rosette of 12 Niskin bottles

Photo Gallery

A collection of photos illustrating this investigation's activities.

More Information

USGS scientist sampling Ear Spring, Wyoming. Old Faithful is erupting in the background

More Information on the Mercury in Aquatic Ecosystems Investigation

The USGS mercury research team maintains its own home page that contains additional information about research on mercury in aquatic ecosystems. The research team runs the USGS Mercury Research Laboratory.



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Page Last Modified: June 19 2017