What link between coal plants and mercury?
To the editor:
This is in response to the Dec 13 “Eaglecide” editorial. Commenter Dec. 13 9:37 a.m. says: “I suggest you go on the Minnesota DNR site and read up on fish consumption limits due to the presence of mercury. Guess where that mercury comes from? That’s right coal plants.” I went there and discovered that they found an unexpected rise in mercury in pike and walleye in Minnesota Lakes.
“After declining by 37 percent from 1982 to 1992, average mercury concentrations in Minnesota fish began to increase in the mid-1990s. In the 1996-2006 decade, average mercury concentrations increased 15 percent. This is surprising because mercury emissions to the atmosphere in Minnesota and the nation declined sharply during this period.”
So there you have it; as our coal fired plants started cleaning up their emissions, the mercury level in the air increased. Why is that? Note that 90 percent of mercury in the atmosphere comes from outside the state and country. The site also said that one third of the atmospheric mercury is from minerals and volcanoes. But if you include the oceans, it goes up to about two thirds; according to an FDA toxicologist. So it looks like today’s coal plants are pretty much a non-issue regarding the mercury non-problem.
Mercury is a “non-problem” when we consider that selenium is abundant in fish; it has a binding affinity for mercury (like a magnet). When selenium binds to mercury it forms a new substance that cannot bind to anything else, such as brain tissue. So apparently, as long as the selenium level in the fish is higher than the mercury level, we are safe.
The only fish not recommended is Pilot Whale meat, as the mercury content is sometimes higher than the selenium, but if you take selenium supplements you’re OK.
But what about the “recommended safe levels” of mercury? A study done on people of the Seychelles Islands, found no negative effects even though their mercury levels were ten times higher than Americans. One test for mercury levels in humans involves analyzing hair for that element. Alaska’s Public Health Department, reports that when the hair of eight 550-year-old Alaskan mummies was tested for mercury, the results showed levels higher than today’s Alaskans. In another study, Princeton scientists compared samples of yellowfin tuna from 1971 with samples caught in 1998. They expected to find a mercury increase of between 9 and 26 percent, but they found a small decline instead.