The USGS released a report last week that is quite stunning in its implications.
The major findings from USGS Mercury in Stream Ecosystem studies of 291 stream systems across the US are that methymercury (the form easiest for aquatic life to acquire and concentrate) is pretty much everywhere, even in pristine areas. Every stream, every fish, every watershed.
The culprit? Atmospheric mercury.
The cause? Coal plants and other industry spewing mercury and other heavy metals into the air, which dissolves in slightly acidic wetlands and forests into methylmercury.
The problem? Methylmercury is not only very toxic, it probably makes us stupid.