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Mercury in Fish

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Mercury in fish

Which fish were highest in mercury?

Flathead catfish,drum, largemouth bass, and blue catfish had the highest levels of mercury. White crappie, sunfish, spoonbill, channel catfish, white bass, and smallmouth buffalo had lower mercury.

In general, longer fish and fish higher on the food chain tended to have more mercury.

study result table: Mercury in fish

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Were there any fish that had mercury levels of concern?

We found that fish from the Grand Lake watershed generally do not have high levels of mercury. However, our results do show levels of mercury that exceed the EPA guideline of 300 parts per billion for children and women of childbearing age in 3% of the nearly 1,000 Grand Lake fish we tested. These included flathead catfish, largemouth bass, blue catfish, and drum.

study result table: fish consumption

Click to enlarge

Were the mercury levels higher in some parts of the watershed?

Our study does not show that any locations in the watershed should be avoided because of high mercury levels in the fish. Most of the fish with high mercury levels were caught in the Neosho River. In particular, flathead over 40 inches and drum over 18 inches from the Neosho tended to be high in mercury.

Harvard School of Public Health LEAD Agency university of Oklahoma Health Sciences Center logo

National Institute of Environmental Health Sciences The Grand Lake Watershed Mercury Study is supported with funding from the National Institute of Environmental Health Sciences Grant No.1R21ES017941.

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