NAS Backs EPA Mercury Toxicity Findings

Methyl-mercury exposure is a “widespread and persistent problem in the environment” and may cause neurological problems in 60,000 children born in the U.S. each year, according to a report released today by a panel of National Academy of Sciences experts.

The report confirms Environmental Protection Agency studies regarding the mercury’s toxicity, and says that the Agency is justified in calling for strict regulations of mercury emissions.

“The NAS study will reinforce and underscore the science that we use to make those [regulation] decisions,” EPA spokesman Dave Cohen said, adding that the agency was very pleased with the NAS results.

Regulation Plans Stalled

The NAS report, which concludes an 18-month review of the science used by the EPA in establishing new guidelines for protecting the public from mercury contamination, eliminates a key obstacle to EPA plans to regulate mercury from power plants.

Regulation plans were stalled for nearly two years after Congress, citing “gaps in the scientific data” used by the EPA in determining mercury’s toxicity, banned the agency from further developing mercury regulations in 1998.

Noting that the EPA relied upon conflicting studies — one on the health impact of low-level mercury exposure to children in the Seychelles Islands in the Indian Ocean, and the other in the Faroe Islands off Scotland — Congress ordered the NAS to review the agency’s methods and conclusions.

The Faroe study found adverse developmental effects among children whose mothers, while pregnant, were exposed to relatively low levels of mercury in fish. But the Seychelles study found no discernible link.

“The NAS looked at key studies and concluded they were all good, but not all of them were appropriate for a recommendation. The report concluded that the Seychelles study should not be used [to determine the health effects of mercury emissions] because it was the only one that did not show effects,” explains Felice Stadler, Policy Director of the Clean Air Network in Washington, D.C.

Justifiable Recommendation

Calling the EPA’s current reference dose for methyl mercury, “a scientifically justifiable level for the protection of public health,” the NAS panel says there is strong evidence to link mercury exposure to neurological problems, including learning disabilities, as well as immune system and cardiological problems.

“Given this new information a lot of people are at risk in the United States, particularly in the context of power plants,” says University of Maryland Medical School toxicologist Ellen Silbergeld, Ph. D.

While much remains to be learned about low-dose mercury contamination and human health, the study says children of women who consume large amounts of fish and seafood during pregnancy face a much higher risk of developing neurological problems, including learning disabilities, because of low-level mercury contamination through their mother prior to birth.

The largest sources of mercury, about 40 tons annually, comes from coal burning electric power plants. The EPA has sought to develop standards for regulating these emissions, which often find their way into lakes and streams and onto pasture land, and eventually into the food chain, especially in fish.

“Because of the beneficial effects of fish consumption,” the NAS report states,”the long-term goal needs to be a reduction in the concentrations of methylmercury in fish rather than a replacement of fish in the diet by other foods.”

The EPA has taken action on mercury emissions in municipal waste combusters and hazardous and medical waste incinerators and is required by Congress’s Clean Air Act to have regulation recommendations on mercury emissions from coal power plants in place by the end of this year. The Associated Press contributed to this report.