Grand Lake Mercury

Grand Lake Watershed Mercury Study


PI: Laurel Schaider

Collaborators: Earl Hatley (LEAD Agency), Rebecca Jim (LEAD Agency), Robert Lynch (University of Oklahoma Health Sciences Center

People: John Spengler, James Shine, Zhao Dong


Grand Lake is an important recreational and ecological resource, but there are concerns about water quality in the lake. In recent years, residents have seen that pollution is having visible effects on water quality. Pollution may also have less visible, but still important, effects on the lake’s water and ecology. For instance, the Oklahoma Department of Environmental Quality issued a state-wide fish consumption advisory because of concerns about mercury levels in fish, especially predator fish like largemouth bass and flathead catfish. However, little is known about mercury levels in fish caught from the Grand Lake watershed and whether people who eat fish from Grand Lake are exposed to high levels of mercury in their diet.

Our study area

Map of study area_s

We tested over fish from all parts of Grand Lake and its major tributaries, including Spring River, Neosho River, Elk River, and Honey Creek. We also tested fish from Lake Hudson. Our participants live in over 20 towns throughout Ottawa and Delaware Counties and other parts of Oklahoma, Kansas, and Missouri.

Harvard School of Public Health. L.E.A.D. Agency and the University of Oklahoma Health Sciences Center received a grant from the National Institute of Environmental Health Sciences to study mercury levels in fish from the Grand Lake watershed and mercury exposure in people who regularly eat fish from the Lake.

Fish collection and mercury analysis


Some of our fish were donated by study participants and other active fishers in the community. Some of our fish were collected in collaboration with the Oklahoma Department of Wildlife Conservation.

We measured mercury levels in all fish collected. In some samples, we collected additional information to help us understand differences in the ecology of the fish, such as their position on the food chain and their typical diet.

Assessing mercury exposure and fish consumption


Participants completed questionnaires about which types of fish they ate over the past 3 months and how often. They also provided hair samples that we tested for mercury. Mercury levels in hair are a measure of mercury exposure in diet.

Participants were asked to complete questionnaires and provide hair samples 5 times over the course of a year so that we could learn if their patterns of fish consumption and their mercury exposure were different in different seasons.


Study Website: http://www.grandlakemercurystudy.org/