Wisconsin Sea Grant has been a leader in funding academic research on toxics and their effects in the environment – within the Great Lakes and other aquatic systems throughout the world. In its 42-year-plus history, the program has funded research, and has had a role in a major international mercury conference.



Researchers Find That Dioxin Exposure Can Impact Fish Noses and Reproductive Tracts
A Wisconsin Sea Grant-funded researcher discovered dioxin could have a negative impact on the nose tissue and sexual development of rainbow trout and zebrafish. Read more...

Research Findings

Dioxin in the Details
UW Sea Grant researchers identify a key gene in zebrafish that responds to microscopic doses of a deadly environmental toxin. Read more...

Flame Retardants Affecting Frogs
UW Sea Grant researcher Dr. William Karasov has shown that commonly used manufacturing flame retardant increases mortality and stunts the growth of tadpoles. Read more...

World Health Organization Adopts Fish Assessment Tool
The World Health Organization has looked to Wisconsin Sea Grant researchers and found an important way to monitor pollution's effects on developing fish. Read more...

Nuisance Algae in Lake Michigan
Learn the conditions that favor the growth of Cladophora, a filamentous green algae common in the Great Lakes, and what can be done to manage it. Read more...

PCBs in Green Bay
Wisconsin Sea Grant has funded research on PCBs in Green Bay and the Fox River Watershed. A thorough fact sheet provides details. Read more...

Checking Beaches for Contaminants
Sea Grant has funded researcher Sandra McClellan at the University of Wisconsin-Milwaukee who is on the hunt for what stew of contaminants it is that closes beaches in the summer to protect people's health. Read more...


Sea Grant Sponsored International Mercury Conference
Wisconsin Sea Grant devoted considerable resources to the 2006 8th International Conference on Mercury as a Global Pollutant. The full conference videos, abstracts and declaration are available. Read more...

Podcast: Water, Wisconsin and the Mercury Cycle
This five-part series explores the long and tangled relationship with mercury, focusing on Wisconsin's environment and culture to demonstrate the complexities of dealing with this intriguing metal. Read more...

Wisconsin Contaminant Facts

In Great Lakes Water and Sediment

More than 800 toxic contaminants have been identified in Great Lakes water and sediment.

Lots of Nitrogen Annually

More than 2 billion pounds (900 million kilograms) of nitrogen is added to Wisconsin soil annually, 80 percent of it from commercial fertilizers, manure and legumes.

Arsenic - Naturally Occuring but Unnaturally High Levels

Arsenic occurs naturally in Wisconsin groundwater, but unnaturally high concentrations have been found in 23 of the state’s 72 counties.

Nitrate is a Common Contaminant

Nitrate—most of it from fertilizers—is by far the most common chemical contaminant found in Wisconsin groundwater.

Nitrates in Private Wells

Statewide, nitrate levels exceed state and federal standards in 10 percent of the private wells sampled.

Nitrates in Public Water Systems

Fifteen Wisconsin municipalities must treat their water to reduce nitrate levels.

Mercury Advisory

In 2002, Wisconsin issued a statewide advisory for mercury in all of its inland waters.


Revitalizing Local Waterfront Economies
This video outlines the Great Lakes Legacy Act and highlights benefits it brings to communities. Read more...

Visualizing the Effects of Dioxin on Fish
Some beautiful images convey the deadly effects of the class of chemicals known as dioxin in zebra fish -- and possibly other species, like the very sensitive lake trout.

Evolution at Sea Grant
Dr. Anders Andren describes how Sea Grant has changed during his time with the program. Read more...

Are Flame Retardants Harming Frogs?
In Dr. William Karasov's lab, a series of research experiments are designed to explore how environmental toxins may be affecting the frog's immune system, growth and development. Read more...

A Satisfying Career
As he prepares for retirement, Dr. Anders Andren reflects on some of his scientific accomplishments and and the collegial satisfaction he's received over the years. He also tells us what he'll miss most about directing the Wisconsin Sea Grant Institute. Read more...

A Message from the Director
Dr. Anders Andren, director of UW Sea Grant, provides an overview of the program. Read more...


The Basis for Microbially Mediated Mercury Methylation in Oxygen-Depleted Zones of the Great Lakes

Katherine McMahon, UW-Madison, (608) 263-3137,

Elevated levels of the potent neurotoxin methylmercury (MeHg) are present in fish throughout the Great Lakes. An inability to balance sources and sinks of MeHg in aquatic ecosystems suggests that we are missing significant processes and/or locations of MeHg production. In this project, we will test hypotheses about the organisms and their genes expected to be responsible for Hg methylation in the Great Lakes. We will use molecular techniques to relate microbial community composition to MeHg and total Hg levels at depth-resolve intervals within the water column of all five Great Lakes, at stations known to have significant MeHg concentrations. We will also target recently identified genes known to be involved in methylation in pure cultures of anaerobic bacteria. Finally, we will evaluate the effect of thiols on methylation in lake microbial communities. This work will advance our understanding of the freshwater Hg cycle, providing evidence for the mechanisms at play in microbial communities mediating methylation.  R/HCE-22

An In Situ Molecular Detection System for Microcystin Monitoring

Matthew Smith, UW-Milwaukee, (414) 382-1700,

Human activities are increasingly causing eutrophication of water supplies, which has led to an increase in toxin-producing organisms such as cyanobacteria. Of these toxins, microcystins are a group of hepatotoxins that have been shown to cause adverse health effects in humans and animals even at low concentrations. There is a need for instruments capable of making autonomous, species-specific, microbiological measurements that can serve as early warning systems for toxic metabolites in freshwater systems. We propose to develop a field-portable autonomous instrument that can be deployed in water bodies for extended periods (~1 month) and provide near real-time detection of microcystin. The proposed instrument will decrease the labor requirements of routine monitoring, while increasing sampling resolution during dangerous or inconvenient times. R/HCE-23

Refining Our Understanding of Methylmercury Production and Bioavailability in the St. Louis River Estuary

Matthew Ginder-Vogel, UW-Madison, (608) 262-0768,
Kristofer Rolfhus, UW-La Crosse, (608) 262-0768,

The St. Louis River Estuary (SLRE) is a valuable fish spawning ground for the western arm of Lake Superior. However, preliminary data suggest that higher mercury levels are found in walleye that feed within the SLRE than those that feed in Lake Superior. Methylmercury (MeHg), the bioaccumulative form of mercury, is primarily produced by microbial activity in anaerobic wetlands, soils and sediments that are abundant in estuarine environments, such as the SLRE. Although the underlying cause of elevated mercury levels in fish in the SLRE is unknown, it is likely due to a combination of biogeochemical factors including solid-phase Hg speciation, coupled with variations in water chemistry (e.g., dissolved sulfate and organic carbon). Developing an understanding of these fundamental biogeochemical processes is critical to the ability of resource management agencies to make effective decisions concerning the beneficial use of future dredging materials and habitat restoration in the SLRE. R/HCE-30

The Role of Indirect Photolysis in the Environmental Fate of Pesticides and Pharmaceuticals

Christina Remucal, UW-Madison, (608) 262-1820,

The presence of biologically active anthropogenic compounds (e.g., pesticides and pharmaceuticals) in the watersheds of the Great Lakes is of emerging concern to stakeholders and water quality managers. Natural processes, such as dissolved organic matter (DOM)-mediated indirect photodegradation, can transform many of these compounds. However, predicting the photodegradation rates of target compounds is difficult because DOM varies temporally and spatially, and current approaches rely on time- and labor-intensive analyses. The overall goal of our project is to assess how the molecular composition and photochemical reactivity of DOM with anthropogenic compounds changes as it moves from the St. Louis River into the St. Louis Estuary and then into Lake Superior. We plan to develop a transferable tool that will relate the photoreactivity of DOM with simple water quality measurements and predict the photodegradation rates of target compounds in this sensitive ecosystem and other natural waters. R/HCE-31

Related Publications

Visit Our Publications Store
For print and downloadable information about contaminants and toxins, visit our online publications store. Read more...

Related Websites

Wisconsin's Water Library
Established in 1964 by the UW Water Resources Institute, Wisconsin's Water Library (formerly known as the Water Resources Library) is unique among UW-Madison's many libraries for its collection of almost 30,000 volumes of water-related information about the Great Lakes and the waters of Wisconsin. The library includes a curriculum collection, dozens of educational videos, a children's collection, and more than 20 journals and 100 newsletters. Read more...

Related Topics on This Site

Habitats and Ecosystems
Water Quality