The Controversy Over the Seychelles and Faroe Islands Studies on the Health Effects of Chronic Exposure to Mercury

Actions to address mercury pollution were first watered-down in 1990 when Congress avoided regulating mercury emissions in the Clean Air Act and instead required EPA to provide a report on mercury by November 1994. Although the report was effectively completed in December 1995 and extensively peer reviewed, its release was been continuously delayed due to pressure from the utility and fishing industries.

Several federal agencies and members of Congress pressured EPA to send the Mercury Study Report to Congress to its Science Advisory Board (SAB) in June of 1996 for review of the health effects data, especially the applicability of two new studies from the Seychelles and Faroe Islands on mercury consumption among subsistence fishers.

The SAB reviewed the report and urged that it be released to Congress without further delay, stating that nothing in the Seychelles or Faroe Islands health studies should lead EPA to revise the report or its proposed reference dose. The SAB panel members strongly questioned the preliminary conclusions from the Seychelles study, which found little effect on 1,500 children whose mothers consumed methylmercury in seafood during pregnancy. At the time, none of the Faroe information had been made officially public.

The Faroe Islands study found that pregnant women who have levels of mercury in their blood considered safe by the World Health Organization (WHO) bear children who later show deficits in learning, memory, attention, and other skills. The extent of the neurological damage varies with the level of mercury exposure. This report demonstrates for the first time that mercury levels previously considered safe are damaging babies and affecting children's intellectual and mental development.

The Seychelles study found a marked decrease in motor activity in two year old boys whose mothers had eaten mercury contaminated fish during pregnancy. The Ministry of the Environment in Ontario has used this effect to substantially lower the amounts of mercury considered safe for women of child-bearing age and children under the age of 15. In contrast, the Agency for Toxic Substance Disease Registry (ATSDR) has ignored the finding of decreased motor activity and relied on the Seychelles study to set a limit for mercury exposure three times higher than the level proposed by EPA.

Since there is a controversy over the implications of both the Faroe and Seychelles Island studies and the studies are ongoing, EPA has relied on data from an acute poisoning incident which occurred in Iraq in the early 1970's to base their proposed reference dose of 0.1 mg/kg body weight/day.

Last year, Congress passed legislation asking the National Academy of Sciences to examine the controversy and make a recommendation to Congress on a proposed reference dose for mercury. This effort is ongoing.