Assessing Winter Mercury Patterns in Lake Champlain Basin


February 1, 2020 to October 31, 2023


Mercury is an important fish contaminant of concern in the Lake Champlain basin and globally due to its persistence in the environment and threat to wildlife and human health. Despite its importance, our understanding of Hg has largely focused on patterns measured during the summer and to a lesser extent, spring and fall. Researchers will investigate mercury bioavailability (the ability to be taken up and incorporated into the body) and bioaccumulation (buildup in organisms and lake food webs) into the Lake Champlain food web during the winter in comparison to other seasons. During each season (through the ice in winter), researchers will sample and measure concentrations of total mercury and methylmercury in lake biota, including zooplankton, benthic invertebrates, and fish from St. Albans and Missisquoi Bays. They will also collect water and sediment samples for mercury analysis.

Findings will help to understand Hg bioavailability and bioaccumulation during winter and whether ice cover supplies or sequesters mercury to the food web. This information fills an important gap and is necessary to predict whether future lake winter conditions are likely to increase or decrease mercury in fish consumed by wildlife and humans. Through community outreach events, researchers will engage the public, specifically those who rely heavily on local fish consumption yet may have limited access to information on the health risks and benefits of eating fish. They will also increase public understanding and awareness of the potential role of climate change in altering risks in the future. Findings can be used to inform revisions of fish monitoring and fish consumption advisories through state agencies.


Roxanne Karimi
Research Scientist and Adjunct Assistant Professor, Stony Brook University
roxanne.karimi [at]

Andrew Schroth
Research Associate Professor, University of Vermont
andrew.schroth [at]

Resulting Publications

Mercury Under Lake Ice

Published 2021
This fact sheet, created by Lake Champlain Sea Grant-funded principal investigators, describes their research project on mercury under the ice of Lake Champlain and its implications and impacts to human health and well-being. The publication describes how researchers are studying mercury uptake into the food chain during the winter and how mercury uptake may change in the future, as winter climate conditions change.