EESI Briefing Summary

Mercury Contamination: How Effective are Regulations?
December 2003

A November congressional briefing featuring Florida Department of Environmental Protection (FDEP) mercury expert Dr. Thomas Atkeson presented the findings of a recently finished decade-long study sponsored by FDEP and the US Environmental Protection Agency (EPA). The study finds that regulatory efforts to reduce local and regional mercury emissions can translate into dramatic benefits for areas with high levels of methylmercury contamination.

In the mid-1990s state and federal agencies began to regulate out-of-date municipal and medical-waste incinerators in southern Florida .  When combined with pollution prevention actions taken in the late 1980’s that reduced mercury input to incinerators, these policies achieved a decline in incinerator mercury emissions in south Florida of approximately 92 percent between 1991 and 1999. Mercury found in wildlife in the Everglades also declined by roughly 60-70 percent from its peak in the mid-1990s.^[1]  Study coordinator Dr. Thomas Atkeson notes that the approach taken in southern Florida has translated into tangible results faster than previous estimates would have predicted.

What is mercury?

Mercury is a naturally-occurring metallic element found in the earth’s crust as well as in circulation in terrestrial, marine, and atmospheric environments. As a chemical element, mercury cannot be created or destroyed; it can, however, be circulated through the air and deposited in water and soil. As with all elements, mercury can change chemical states to bond with other elements, to form various compounds. Most mercury on earth is generally found in one such compound, cinnabar (or mercury sulfide, HgS), which has been produced in mines for perhaps two thousand years.^[2]

The elemental form of mercury is rarely seen in its pure metallic state, as shiny, silvery droplets that readily flow as a liquid at room temperature. For centuries, when and where it has appeared in this form it has captivated human attention. Ancient peoples ascribed to mercury mythical, magical and religious importance as an element with the dual nature of having both medicinal and poisonous properties. Only in the last century was it realized that the native pharmacopeias based on mercury in various parts of the world were based more in mystique than in medical knowledge.

In the current debate over mercury contamination, three forms of mercury have taken center stage—methyl, elemental, and oxidized.  Inorganic, elemental mercury (Hg0) released by combustion sources and mine wastes is not a problematic emission in and of itself. Mercury becomes dangerous to ecosystems through a two-step transformation to the most toxic and bioaccumulative form of mercury, methylmercury (MeHg). Elemental mercury in the atmosphere and in watershed runoff is first oxidized by complex organic and inorganic reactions into its reactive, water-soluble form (Hg2+). Only reactive mercury can undergo “methylation,” the second set of reactions necessary to form methylmercury from elemental mercury. Methylation is a microbial process controlled by sulfate-reducing bacteria and a handful of other chemical and environmental factors. It is only once mercury is methylated that it enters the ecosystem, traveling up the food chain to humans through the consumption of affected fish. When scientists and commentators talk about the dangers of mercury contamination, they are almost exclusively referring to methylmercury.

How does mercury affect public health?

A strong body of scientific evidence shows that methylmercury is a powerful neurotoxin that poses significant threats to public health.  According to EPA, high doses of mercury can impede motor function and cause tremors, convulsions, and even death.   More commonly, mercury poisoning occurs at smaller levels and can cause damage to the senses and brain. 

Studies also show that it is the developing fetus that is especially vulnerable to mercury contamination.  The National Academy of Sciences (NAS) estimates that more than 60,000 U.S. babies born each year are at risk for neurodevelopmental damages caused by methylmercury, and EPA has put that figure between 52,000 and 276,000.  Analysis suggests that children of women who were exposed to methylmercury at high levels display a variety of effects, including, but not limited to, delayed onset of walking and talking and reduced neurological test scores.  When women are continually exposed to smaller doses of methylmercury, children have exhibited delays and deficits in learning ability.

Contaminations are also played out on a macro-scale.   In the 1950s at Minamata Bay in Japan , methylmercury in the effluent from a plastics factory was ingested by fish and, eventually, by people in the fishing communities on the bay.  More than 900 victims died in agony, and many babies in the area were born deformed. Thousands of victims were ostracized, first out of a mistaken fear that the disease might be contagious and later because their legal suits drew unwanted attention to the region.  Another well known outbreak, this time of alkyl mercury, occurred in Iraq in 1971, resulting in 6,000 hospital admissions and 500 deaths from bread made from imported seed grain dressed with methylmercury fungicide.  And, while it is true that progress has been made, the health effects of mercury is still an issue for communities around the country.  A January 2003 report by the Centers for Disease Control and Prevention found that 1 in 12 women of childbearing age has mercury levels above the safe health threshold established by the EPA.

Where does extra mercury come from?

One challenge of shaping public policy with regard to mercury has been a lack of knowledge about the amounts of mercury that are in water, sediment, and fish, and the processes by which mercury gets there.  To this end, the United States Geological Survey (USGS) has compiled data on mercury and methylmercury in various areas across the country.  The sampling studies have produced a large amount of new information that has enabled USGS to extrapolate trends, debunk myths, and establish specific regions of concern. 

One possible source of mercury methylation previously unstudied comes from wetland areas.  Studies have demonstrated that “drying and rewetting” cycles in the Florida Everglades result in the production and bioaccumulation of a substantial amount of methylmercury.  In other words, as the Everglades go through their yearly cycle from water saturation to dryness, a significant amount of methylmercury is released.  It appears that the drying and rewetting cycles cause soils and sediments in the Everglades to go through a period of oxidation followed by a period of deoxidation.  As a result, mercury methylation becomes exacerbated.    In fact, the highest levels of methylmercury ever seen in the Everglades by the USGS resulted from a drying and rewetting cycle, as opposed to any known “mercury-loading” event where mercury is released directly into an ecosystem. 

The studies also found that the Northeastern United States is one of the greatest problem areas for methylmercury accumulation.   In samples collected from 112 sites, USGS found that 40 percent of fish contained mercury levels higher than the EPA recommended level of .3 ppm (parts per million).  Furthermore, as a startling indication of just how much human activity contributes to mercury contamination, sampling in New England found that mercury levels sharply increase the closer one gets to urban areas. 

Why is mercury regulation an energy issue?

Rarely are energy concerns divorced from those of the environment, and the issue of mercury contamination is no different. Mercury is emitted as a byproduct of coal and oil combustion for power generation. Emissions from power plants constitute about 40 percent of total U.S. mercury emissions annually. As such, any attempt to regulate overall mercury emissions would likely be associated with significant compliance costs for energy producers.

How does industry view the mercury issue?

The energy industry acknowledges that the bioaccumulative properties of methylmercury can make it dangerous to public health. However, industry advocates and research groups, including the Edison Electric Institute and the Electric Power Research Institute (EPRI), assert that the majority of mercury emitted from power plant smokestacks is of the elemental variety, which tends to circulate globally in the atmosphere for a year or more. They contrast these power plant emissions with waste incinerator emissions of already oxidized mercury, which can be rapidly taken up in rain water, snow, or adsorbed onto small particles, and be subsequently deposited in the environment. They contend that forcing power plants to install antipollution equipment would not necessarily ensure a reduction in methylated mercury levels in the local environment.

Industry backers cite caveats in even the most recent studies on mercury contamination which admit that the environmental factors and chemical processes that determine the rate of methylation of mercury are not completely understood by the scientific community, and argue that accurately predicting the effects of a single mercury standard in different ecosystems is probably not possible without further research. Utilities argue that any legislation must address the scientific uncertainties and complexities unique to the issue of mercury pollution, giving them some flexibility in their response to the issue, and weighing known costs against potentially unknown benefits.

What is the case for greater regulation?

Environmentalists argue that the threat mercury poses to human populations cannot be ignored. They point to fossil fueled power plants as the major remaining source of mercury emissions and argue that reducing mercury emissions from these sources is a necessary step in reducing local deposition of mercury. A recent report released by Northeast States for Coordinated Air Use Management (NESCAUM) contends that mercury emissions from coal-fired power plants could be reduced by more than 90 percent. NESCAUM says that reductions could come by utilizing various existing technologies, such as those that reduce mercury emissions as a co-benefit of limiting emissions of other pollutants, or those that are used to target mercury from municipal waste incinerators, all without undue economic burden.

Although they concede that much uncertainty remains about the process of mercury distribution and methylation, many government officials argue that attempts to dismiss emissions of elemental mercury as harmless are limited by the same scientific uncertainties, noting that elemental mercury can easily turn into oxidized mercury in atmospheric, terrestrial, and marine environments. Proponents of regulation believe that based on the Florida study and others, the processes at work are sufficiently understood to craft abatement policies.  While acknowledging that differences in ecosystems and coal combusted in different parts of the country will affect the rates of improvement, they point to the fundamental finding of the Florida study – that reductions in emissions of mercury from local sources will be reflected in proportional reductions in mercury in fish. Noting that 45 States have mercury advisories warning citizens about the mercury content of local fish and wildlife, they argue that action is needed to control mercury emissions from coal-fired power plants. They also argue that by proposing a mercury control rule now that requires application of mercury emission control technologies, EPA can give industry the measure of certainty it needs to spur market forces to adequately protect public health.

What has already been done to regulate mercury levels in the environment?

The regulation of mercury has historically been a collective effort of several agencies rather than one cohesive set of regulations.  Mercury controls are in place at both the state and federal level and are managed by multiple agencies.  For example, on the federal level, mercury contamination is monitored by EPA, the Food and Drug Administration (FDA), and the Occupational Safety & Health Administration (OSHA).  Thus far, there exists no one statute at a federal level that has singled out mercury as a sole source of concern. Instead, mercury is one substance out of many covered by a variety of statutes in a variety of locations.  However, as the effects of mercury on ecosystems and public health become increasingly clear, the call for a national plan on mercury regulation has become stronger. The lead statutory authority for controlling mercury emissions is Section 112 of the 1990 Clean Air Act.  Section 112 states that mercury is subject to the MACT (Maximum Achievable Control Technology) and residual risk provisions of Section 112.  Together, these provisions ensure that mercury is monitored.

A special provision was included in Section 112 for power plants, requiring EPA to study the public health effects of air toxic emissions from electric power plants that burn fossil fuels and to determine whether it is necessary to regulate those emissions.  This resulted in two reports published for Congress by EPA: in 1997, EPA identified fossil fuel plants as the single greatest source of mercury contamination, and a 1998 Air Toxics report found that mercury was the toxic of greatest concern out of a list of roughly 168 pollutants.  Further EPA research found that of fossil-fuel burning plants, coal-fired units are the largest source of human-caused mercury emissions in the U.S. , releasing roughly 43 tons of mercury each year.  The EPA is required by court order to propose regulations to reduce mercury emissions from coal and oil fired plants by December 15, 2003 , promulgate a regulation by December 15, 2004 , and have it fully implemented by December 15, 2007 .

** NOTE: On December 3, 2003 , news organizations reported that the Bush administration is considering eschewing regulation under Section 112 in favor of a new plan to regulate mercury under Section 111 “New Source Performance Standards.” 

News sources are reporting that new White House Office of Management and Budget (OMB) documents assert that EPA erred when it declared that mercury was the kind of toxic substance for which the Clean Air Act requires strict pollution controls. The proposed EPA policy revision would rescind a legal document to that effect, signed by Carol Browner, the EPA administrator under President Clinton.

Although administration officials claim that a cap-and-trade system would eventually result in greater emissions reductions, critics argue that the proposed change would effectively exempt all coal-fired power plants from mercury regulation for the foreseeable future. Under the proposed plan, mercury would be subject to a New Source Performance Standard (NSPS) instead of the requirements of Section 112. As the name implies, NSPS applies only to newly-built and modified power generation units. Critics of the proposal argue that because recent EPA rule changes muddle the definition of “modify,” as a practical matter, all currently existing coal power plants would be exempted from mercury regulation while still meeting the court-imposed rule deadline.

Under the Administration’s proposal, existing fossil fueled power plants would be regulated, if at all, by a cumbersome State-by-State program under Section 111(d) that would require each State to establish its own mercury control program for existing fossil fuel-fired units.  The EPA would establish a target for national emissions, and would encourage States to adopt trading programs that would allow individual power companies to meet the State-established limits however they wished. States would be encouraged to issue credits to companies that made greater emission reductions than required which companies could then sell to those unable or unwilling to comply.

The EPA proposal would set a national mercury emissions target from power plants from of about 34 tons by 2010, This target, which EPA could not enforce, is even less ambitious than limits agreed to by both the administration and utilities in the President’s Clear Skies Initiative.

Critics worry that even if the proposed policy is ultimately thrown out by the courts, years of litigation would give the power companies additional time to avoid compliance with Clean Air Act provisions regulating toxic air pollution.**

What are the possibilities for future mercury regulation?

Congress has attempted to address mercury pollution by including it in “multipollutant” bills that target Hg (mercury), NOx (nitrogen oxides), SO2 (sulfur dioxide) and, depending on the bill, CO2 (carbon dioxide).  Two of three legislative proposals put forward in the 107th Congress would cap mercury pollution from electricity generators – President Bush's Clear Skies Initiative and Sen. Jim Jeffords’ (R-VT) bill – were reintroduced in the 108th Congress with updated time tables and some other new features.  A third multipollutant bill (S. 843) has been reintroduced by Sen. Tom Carper (D-DE). In terms of mercury contamination, S. 843 represents somewhat of a middle ground between the two bills, setting caps at 24 tons by 2009 and 10 tons by 2013.  An additional option is Sen. Patrick Leahy’s (D-VT) mercury-only bill, S. 484, which is currently pending in the Senate Committee on Environment and Public Works (EPW).

Clear Skies Act

The President’s Clear Skies Act (S. 485, H.R. 999) would establish federally enforceable emissions limits ("caps") for NOx, SO2 and mercury. It does not address CO2. These limits would apply to all fossil fuel-fired electric generators greater than 25 megawatts, although the mercury requirements would only affect units that are coal-fired.  The targets for mercury would be a cut from 1999 emissions of 48 tons to a cap of 26 tons in 2010, and to a cap of 15 tons in 2018.  The bill would also institute an emissions trading system that would allow power plants to buy and sell pollution credits among each other, as long as they were meeting emission standards.

Also, it should be noted that the residual risk requirements of Section 112(f) of the Clean Air Act, which empower EPA to promulgate more stringent mercury standards if needed to provide "an ample margin of safety to protect public health" as early as 2015, would be eliminated under the Clear Skies bill.

In November, Sen. James Inhofe (R-NE) introduced a rewrite of the President’s Clear Skies Act, S. 1844 which would raise the first mercury cap, in 2010, to 34 tons.

Four Pollutant Bill - The Clean Power Act

Introduced in the Senate by Jim Jeffords (I-VT), Susan Collins (R-ME) and Joseph Lieberman (D-CT), S. 366 proposes to cut emissions from all four pollutants: Hg, NOx, SOx, and CO2. It would do so on a much shorter timetable than the Clear Skies bill, with the majority of reductions to be completed by 2008.   Proponents of the four-pollutant bill estimate that under S. 366, mercury emissions would be cut 90 percent from 1999 levels by 2008.  Unlike Clear Skies, it would not allow power plants to trade mercury emission allowances with each other.

As a point of comparison, S. 366 proposes to reduce the annual national emissions of mercury to not more than 5 tons by 2008; Clear Skies proposes to set a cap of 15 tons by 2018.  The Jeffords bill would do so by requiring every power plant to meet the most recent pollution control standards for new pollution sources, given that many of the most polluting power plants still in use today were exempted from the original Clean Air Act requirements enacted more than 30 years ago.

How will scientific questions affect the future of legislation?

Most debate over mercury regulation stems from a few scientific questions that are critical to any final decisions on mercury policy, but have yet to be fully answered. One area of uncertainty is whether newly deposited mercury is more dangerous to ecosystems than "old" mercury, released during industrial development of the last century.

Findings by the U.S. Geological Survey have contradicted the assumption that "old" mercury that currently exists in soils and sediments of ecosystems could continue to actively cycle in the environment and fuel the current mercury problem. These findings show that "new" mercury from contemporary emissions is more active than old mercury in the environment, and thus more responsible for driving methylmercury production and bioaccumulation. In other words, the longer mercury is in an ecosystem, the less it is seen in food webs, and the less likely it is to affect human health.  In one experiment conducted by USGS, two-year old mercury was not even detectable in fish. 

This lesson is transferable to the policy realm, where disagreement remains about the timeline under which mercury reductions should be enforced.  Because the studies suggest that mercury is much more potent in the beginning of its lifespan, from a public health point of view, it seems clear that policy options ought to be aimed at shorter rather than long-term reduction timelines.

Even more contentious debate centers on how emitted mercury travels in the atmosphere and is deposited to the terrestrial environment. A greater understanding of the extent to which the various forms of mercury deposited on local, regional, and global levels could have a significant effect on any attempt to regulate mercury emissions. “The outcome of this question is important in determining whether mercury emissions should be reduced through a trading scheme or plant-by-plant,” says Susannah Foster, a professional staff member for the Environment, Technology and Standards Subcommittee of the House Committee on Science. “Trading schemes assume that the benefit will be the same regardless of where reductions are achieved; that there will be little or no local impact.”

The study released by the Florida DEP this month found that the large reductions in mercury emissions from Florida municipal waste and medical incinerators over the last decade has had a significant impact on mercury deposition rates at study sites in the Everglades. Study authors say that during the period when mercury deposition rates were peaking in Florida (1987) conservative estimates put the locally-emitted share of the mercury deposited at over 50 percent.

The Florida study indicates that reductions in mercury deposition in the Everglades during the period 1991-2000 have led to a linear, almost one-to-one reduction in methylmercury bioaccumulation in food webs. This has translated to a 60 percent or greater reduction in mercury levels in fish and wildlife, in accordance with models that predict a 90 percent reduction in the next 20 years with sustained reductions in mercury deposition. The take-home message of the study, says Dr. Atkeson, is that “if you can take the steps to bring those facilities under control, you will see the benefits of it within your local air-shed, and within a reasonable period of years. It will not take forever to see the results of policies to bring down mercury deposition.”

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The preceding summary is the result of a briefing on mercury contamination hosted by The Environmental and Energy Study Institute (EESI), entitled “Mercury Contamination: How Effective are Regulations?”  The briefing was held on November 17, 2003 , and featured the following speakers:  

• Susannah Foster, Professional Staff Member, Environment, Technology and Standards Subcommittee, House Committee on Science
  
• Dr. Thomas D. Atkeson, Coordinator, Mercury and Applied Science, Florida Department of Environmental Protectio n                               
  
  Click here to see Dr. Atkeson's presentation

Information in the summary also comes from two briefings on mercury contamination hosted by The Environmental and Energy Study Institute (EESI).  The first briefing focused on the scientific basics of mercury contamination in the United States, and the second briefing concentrated on regulatory and legislative policy options being proposed to deal with the issue.   Details on those two briefings are as follows:

What We Know About Mercury Part I: Sources, Deposition, Methylation and Health Effects ( February 28, 2003 )

·         Dr. David Krabbenhoft, Research Scientist, USGS  (Presentation)

·         Steve Wordelman, Chair, Water Environment Federation’s Government Affairs Committee; President, Jones and Henry Engineers Ltd., Toledo, Ohio

What We Know About Mercury Part II: Regulatory and Legislative Policy Options Being Proposed To Deal with Mercury Contamination (March 7, 2003)

·         Ellen Brown, Policy Advisor, Office of Policy, Analysis, and Review (OPAR), Environmental Protection Agency  (Presentation)

·         Larry Parker , Specialist, Energy and Environmental Policy, Congressional Research Service

For more information about any of these briefings, please contact Josh Alban at EESI at 202-662-1885 or jalban@eesi.org.