Mercury is a neurotoxin. The Environmental Protection Agency says mercury can be especially harmful for babies and kids. Mercury can affect their developing brains and harm their memory, attention, language and motor skills.
Mercury is naturally-occurring. Volcanoes emit mercury and so do hot springs, like the ones in Yellowstone National Park.
But the EPA points out... the largest manmade source of mercury emissions in the U.S. comes from coal-burning power plants.
Joel Blum is a professor of Earth and Environmental Sciences at the University of Michigan. Blum says when power plants burn coal, mercury is emitted as a gas.
“In order to become toxic, it has to be transformed into a particular form known as methylmercury which is something that happens in the environment.”
So... mercury falls from the atmosphere, and is converted to methylmercury in the water. That toxic form builds up in fish... and it can build up in us when we eat fish.
But for years... there’s been a big debate about where that mercury goes when it’s released from a power plant smokestack.
“How much is deposited nearby, close to the plant, and how much goes into what we call global pool of mercury - basically goes into the atmosphere and stays there for a long period of time and mixes with mercury from other sources.”
Joel Blum and his colleagues have started to crack that puzzle with some careful detective work. They were able to track mercury emissions from a power plant in Florida... and they found that a high proportion of the mercury ended up nearby.
They did this by looking at chemical fingerprints.