Study Finds No Health Risks for Above-Average Mercury Levels

Published August 1, 2003

A comprehensive study of 643 children, tracked from the womb to 9 years of age, has found no health risks resulting from exposure to above-average levels of mercury in their diets. The study calls into question ongoing state and federal efforts to further regulate mercury emissions, which have already sharply declined in recent years.

Scientists at the University of Rochester Medical Center have been tracking hundreds of children in the Republic of Seychelles, an island nation in the Pacific Ocean. Due to its geography, Seychelles citizens tend to eat large amounts of fish, the primary source of human mercury exposure. As a result of their fish intake, Seychelles citizens have an average of six times more mercury in their bodies than do American citizens.

The Rochester Medical Center study found no detectable harms to health among Seychelles children exposed to heightened mercury levels in the womb, and exposed to heightened mercury levels throughout their childhood.

“We’ve found no evidence that the low levels of mercury in seafood are harmful. In the Seychelles, where the women in our study ate large quantities of fish each week while they were pregnant, the children are healthy,”said Gene Myers, senior author of the study and an internationally recognized authority on mercury. “These are the same fish that end up on the dinner table in the United States and around the world.”

The Rochester team conducted a battery of more than 20 tests on the children in the study. Even those children who had far higher mercury blood levels than the Seychelles average showed no adverse effects.

As mercury settles in oceans and freshwater sources, fish take on heightened mercury levels that get passed up the food chain to humans who consume the fish.

Natures Produces Most Mercury

More than half the mercury in the Earth and its environment comes from natural sources. Man-made sources, primarily power plants, produce the remainder of environmental mercury. U.S. power plants account for only 1 percent of global environmental mercury, according to the Center for Science and Public Policy.

Mercury emissions from U.S. power plants declined throughout the 1990s as a result of environmental regulations and advances in technology. The Environmental Protection Agency’s Clear Skies Act aims to cut mercury emissions another 69 percent by 2018. Nevertheless, liberal environmentalists are seeking restrictive and costly additional curbs on U.S. mercury emissions.

According to Harvard-Smithsonian physicist Dr. Willie Soon, “recent findings by the Centers for Disease Control show that the level of mercury found in humans is far below the threshold of health risk, even for sensitive populations.”

Moreover, says Soon, “emerging research indicates that … new [mercury] controls on U.S. coal will mean higher energy prices, more dependence on imported natural gas, and lost jobs–all to address a public harm that has not been found.”

Mercury levels can be reduced more efficiently and economically by targeting natural mercury sources. For example, forest fires release far more mercury than U.S. power plants. Says Soon, “a more effective mercury controlling policy would be to reduce vegetation burning in the U.S. by promoting better forestry management and stewardship and by encouraging similar efforts throughout the globe.”

Concluded Soon, “placing heavier regulatory burdens on already-clean U.S. power plants that will drive up energy prices makes little economic sense. In the face of more realistic and efficient alternatives, it makes little moral or environmental sense as well.”

James M. Taylor is managing editor of Environment & Climate News. His email address is [email protected].

For more information …

A two-page article, “Is the EPA Ignoring the Science on Mercury,” written by Willie Soon and Bob Ferguson for the Frontiers of Freedom Institute, is available through PolicyBot. Point your Web browser to, click on the PolicyBot icon, and search for document #12527.