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Commentary
Mercury's fall from medicine to toxin
By R. Harold Brown
The growing outrage over mercury emissions by power plants seems a stretch, considering that the connection with health is only theoretical and tenuous.
The theory is that mercury falls from the sky, gets in the water, concentrates in fish and poisons people who eat the fish. So the Georgia Environmental Protection Division and the U.S. Centers for Disease Control and Prevention warn people, especially pregnant women, about mercury poisoning from fish.
But the facts say it isn’t so. Just one possible case of sickness from mercury in fish has been documented in the United States. Mercury in tissues of Americans is far below the level associated with sickness. Mercury is decreasing in the environment, not increasing. The use and dumping of mercury has declined dramatically in the last 40 years. And historically, pollution by mercury was mainly by dumping in water, not from the air.
One of the ironies of this pollutant is that it was used to treat illnesses for more than a thousand years. It was so often used to treat syphilis in past centuries that symptoms of mercury poisoning were confused with the disease itself. Two U.S. Presidents, Andrew Jackson and Abraham Lincoln, took mercury for their ailments and undoubtedly suffered the consequences.
Many children of the first half of the 20th century remember taking calomel (Mercurous chloride) at least once a year to “clean out the system,” as a laxative and a dewormer. It was used as a “teething powder” for infants as well as a disinfectant in diaper rinses. Mercurochrome and Merthiolate, containing up to 25 percent mercury, were popular topical disinfectants. Dentists would not only put mercury in fillings, but used formulations of it to sterilize instruments.
It had literally dozens of other uses in industry and everyday life. It was used in mining of gold and in smelting of other metals. In past centuries it was used in the making of felt hats and its neurotoxicity gave the name “mad hatters” to those who used it. In the 20th century, it acquired even more uses. The 1953 USDA Yearbook of Agriculture lists 17 organic-mercury fungicides for seed treatment. Batteries, paints and lamps, thermometers and thermostats contained the poison.
Attitudes about mercury have taken a 180-degree turn from valued medicine and casual use to feared toxin. Once, children used elemental mercury (“quicksilver”) scavenged from thermometers or other devices to shine silver coins, rubbing them between bare fingers. Now, a mercury spill is an “environmental happening.”
Many cases of sickness resulted from both medicinal and careless use of mercury, but not by eating contaminated fish. While we know from the “mad hatters” that mercury is a neurotoxin, we do not know at what level.
All pollutant-caused illness depends on the dose. Two heavily contaminated areas, in Japan and Iraq, provided most of the known information on deaths and injury from mercury contamination of food. In Japan, the cause was fish from heavily contaminated waters; in Iraq, it was grain treated with mercurous fungicide. In the United States, sickness from mercury pollution is very rare.
Overexposure to mercury overexposure, once easy, is not now. Mercury use and pollution has taken a nosedive in this country in the last half-century. After peaking in 1964, its use in the nation decreased by one-third by 1975. The federal Environmental Protection Agency concluded that domestic use of mercury fell another 70 percent from 1980 to 1993; a separate estimate shows use in manufacturing dropped about 75 percent from 1985 to 1996.
Estimated mercury emissions from power plants in Georgia in 1994 were 3,864 pounds. If that amount was equally distributed over the state, about 100 pounds would fall into Georgia waters every year because about 3 percent of the state is covered by water. The other 97 percent would fall on land and would move very slowly toward streams, if at all.
Before 1971, 100 pounds of mercury were discharged, not yearly, but every 10 days by just one plant on the Savannah River. Soon after, it was reduced to less than one-quarter pound per day. Other sources were reduced, too. There is certainly no indication that mercury is increasing in Georgia’s environment; it is just the opposite: Mercury in largemouth bass, for example, has dropped by half since the 1960s.
Linking mercury to sickness in Georgia is a futile endeavor. Ingesting mercury-contaminated fish is believed by most experts today to pose the most danger to health, and unborn babies are said to be at the greatest risk from fish consumption by their mothers. But Georgia’s fish don’t contain much mercury.
The best studies of mercury and health have been done in the Seychelles Islands, where a main part of the diet is fish. The mercury content of the hair of a group of more than 700 pregnant women was compared to the health of their babies and their development. After a series of reports, the lead researcher stated, “These data do not support the hypothesis that there is a neurodevelopmental risk from prenatal MeHg (methylmercury) exposure resulting solely from ocean fish consumption.”
The women in the study had an average of about 6 parts per million of mercury in their hair; the average for mercury in the hair of Americans is less than 1 part per million. A1999 survey of over 700 American women, found 90 percent had mercury levels below 1.4 parts per million. If mercury doesn’t cause sickness in a population with six times as much as in the United States, how likely is it that a problem exists here?
Instead of leaping to conclusions, environmental activists ought to accept that formulation of government policy needs to be based on better connections of pollution and health than is apparently the case being made for regulating mercury emissions from power plants.
University of Georgia Professor Emeritus R. Harold Brown is an Adjunct Scholar with the Georgia Public Policy Foundation and author of “The Greening of Georgia: The Improvement of the Environment in the Twentieth Century.” The Georgia Public Policy Foundation is an independent think tank that proposes practical, market-oriented approaches to public policy to improve the lives of Georgians. Nothing written here is to be construed as necessarily reflecting the views of the Georgia Public Policy Foundation or as an attempt to aid or hinder the passage of any bill before the U.S. Congress or the Georgia Legislature.
© Georgia Public Policy Foundation (Dec. 19, 2003). Permission to reprint in whole or in part is hereby granted, provided the author and his affiliations are cited.