A new study from Duke University, presented at the American Chemical Society conference last week, describes the process by which mercury emissions get converted into more harmful toxic forms of methylmercury through organic reactions in the environment. According to the press release, “Mercury is extremely toxic and can lead to kidney dysfunctions, neurological disorders and even death. In particular, fetuses exposed to methylmercury can suffer from these same disorders as well as impaired learning abilities.” The researchers also note that the most common sources of mercury ingestion are fish and shellfish, due to their “natural tendency to store methylmercury in their organs”.

Coincidentally, the US Geological Survey recently released a detailed report, titled “Mercury in Fish, Bed Sediment, and Water from Streams Across the United States, 1998–2005“. The USGS conducted tests of mercury levels in fish over a period of seven years across 291 rivers and streams in the United States, including agricultural, urbanized, mined, and undeveloped (forested, grassland, shrubland, and wetland land cover) stream basins.

Mongabay.com reports, “Not one fish had escaped mercury contamination. One-quarter of the fish tested contained levels of mercury higher than those deemed safe for humans, and over two-thirds of the fish tested had mercury levels that exceeding those that safe for fish-eating mammals according the Environmental Protection Agency.” The Department of the Interior issued a press release of the findings, noting that the EPA regulates mercury emissions from coal-fired power plants.

Emissions as a result of coal mining and burning enter the air, are precipitated into water systems, then converted to methylmercury and absorbed by fish, who are then ingested by larger fish, and so on. Through this process, high levels of mercury were found in fish even in pristine, protected ecological areas. Coal is the source of more than half of the nation’s electricity. I don’t eat fish, but maybe you do. More importantly, high environmental pollution and elevated levels of mercury affect the wildlife who share our ecosystems, and that’s hardly fair.

How Mercury Becomes Toxic In The Environment.

The Great Beyond: America’s quicksilver fish.