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contaminants

Do not eat the fish because of pfas sign
Lester Graham / Michigan Radio

The State of Michigan is finding industrial chemicals known as PFAS in the tissue of fish. So it's been issuing “Don’t Eat the Fish” advisories along lakes, rivers and streams. But there are concerns about whether state officials are doing as much as they should. 

Before we get too far into the story, we have to start with a little science.

The reason PFAS chemical contamination in fish is such a concern is because of something called bioaccumulation.

U.S. Geological Survey

Researchers with the U.S. Geological Survey have been monitoring pesticides in rivers and streams around the country for 20 years. They just released their findings, and they found there are levels of some pesticides that could be a concern for bugs and fish.

For example, they found the insecticide fibronil at levels that could cause harm. That chemical disrupts insects’ nervous systems.

The study, "Pesticides in U.S. Streams and Rivers:  Occurrence and trends during 1992-2011” is published in the Environmental Science and Technology journal. 

Wes Stone, a hydrologist with the USGS, says some pesticides have been phased out and others have come on the market, and you can see that directly reflected in the water.

“What it shows is to stay on top of what’s in the environment, we’re going to have to constantly evolve and keep looking at the newest ones and evolving new methods to sample for them," he says.

But Stone says their study probably underestimates potential risks to aquatic life. He says there are more than 400 different pesticides in use, but he says funding is limited, so his agency only tests for a fraction of those pesticides in rivers and streams.