[audio:http://wamcradio.org/EarthWise/wp-content/uploads/2012/02/EW-02-15-12-Mercury.mp3|titles=EW 02-15-12 Mercury]
In the Northeast, many ponds — and the fish that live in them — have high concentrations of mercury. Mercury has a long-history as an element toxic to humans, extending at least to the days of Shakespeare. It’s found naturally in the environment, so where do excessive concentrations of mercury come from?
Mercury is one of only a few metals that can exist as a gas. It is emitted from volcanoes, vegetation, and the surface of the sea. Presumably, mercury has been released from these sources since the beginning of time.
But, mercury is also produced during the combustion of coal, and that source is relatively new to our environment.
Mercury travels through the atmosphere as a gas, and it is deposited in areas downwind of emissions in rain and snowfall. In freshwaters, mercury takes on its most toxic form— methylmercury. Here it can make its way up the aquatic food chain, with large fish being the most vulnerable.
And, of course, as consumers of fish, we are at the top of the food chain.
Dr. Charles Driscoll of Syracuse University says government regulation of mercury has helped curb emissions, but we still need to be diligent.
“It seems prudent we would do a good job tracking the effectiveness of this and so I think with a monitoring program in place to measure not only the changes in emissions, but their impact on the environment, that will go a long way to helping us evaluate how effective these control measures are.”
Deposition of mercury in New England is substantially lower than when I measured it in 1971, in one of my first projects as a college science student.
The next time you hear someone criticize the regulation of power plant emissions, don’t ask about jobs vs. environment — ask them about neurotoxins. Is a Saturday morning fishing trip with your kids really worth it, if you can’t eat the fish?
Web extra
Dr. Charles Driscoll of Syracuse University discusses a recent EPA study on mercury contamination levels in the environment…
[audio:http://wamcradio.org/EarthWise/wp-content/uploads/2012/02/Driscoll_extra.mp3|titles=Driscoll_extra]Photo, taken on September 11, 2005 using a Sony DSC-F828, courtesy of Joey Rozier via Flickr.