ARL News

NOAA’s Role In The Mercury Debate Increasingly Recognized


November 18, 2004

The question of how best to regulate and control mercury in the environment is peculiarly suited to examination by NOAA, since the matter extends from the transport of precursors through the atmosphere to the bioaccumulation of its chemical products in fish eaten by humans. NOAA scientists in NOS, NMFS and OAR (especially including ARL and Sea Grant) have been particularly active in exploring how mercury compounds are transported through the environment and end up as materials that are hazardous when consumed. The open question is whether the major threats to human health are due to emissions from nearby or distant sources. The evidence on both sides of this debate is still accumulating, but more and more it is NOAA scientists who are the experts “of choice.”

According to a recent issue of Environmental Science and Technology, industry scientists believe they have data to support the hypothesis that local sources contribute very little to mercury deposition to ecosystems. The matter arose at the Seventh International Conference on Mercury as a Global Pollutant in Ljubljana, Slovenia, in July and at recent meetings in the United States. ES&T quoted ARL’s Mark Cohen as follows –

“This is an extremely important question with huge consequences. If the reduction hypothesis is true, then the scientific rationale for regulating power plants for mercury may be significantly weakened. However, there are many uncertainties, and it is far from clear that the hypothesis is correct. There may be other explanations for the evidence that the industry has presented.”

In reality, the questions that are being addressed focus attention on the need to look at the entire life cycle of mercury. ARL scientists are looking into the atmospheric aspects of the problem, from emissions, through atmospheric chemical reactions, and leading to deposition. Sea Grant, NOS and NMFS scientists are studying the behavior of mercury compounds once they are deposited to ecosystems. NMFS is collaborating with CDC to extend these studies to the eventual uptake and damage to infants and pregnant women. The EPA is, of course, and active partner in these studies. A NOAA-wide initiative has been prepared to bring our forces together to address the mercury issue before major decisions are made about regulations without full understanding of the problem.

A new meeting is now being proposed, to address the question of mercury deposition to the Great Lakes. This international conference will be held in June 2005, at Kingston, Ontario. A centerpiece of discussion is to be the HYSPLIT model of ARL and the need to develop a multi-media capability, to track mercury as it passes through the atmosphere and the terrestrial and aquatic environments before it finally bioaccumulates in the flesh of fish. ARL is one of the two NOAA signatories to the Interagency Steering Committee on Multimedia Modeling, under the auspices of which such new developments are being coordinated. The 2005 meeting will be organized by the International Air Quality Advisory Board of the International Joint Commission.

Contact information: Bruce B. Hicks
Phone: (301) 713-0684