What We Know About Mercury Part II:
Regulatory and Legislative Policy Options Being Proposed to Deal with Mercury Contamination

Friday, March 7, 2003
1:00 - 2:30 p.m.
2318 Rayburn House Office Building
(House Science Committee Room)

  The majority of mercury (H_g) entering lakes, streams, rivers, and oceans comes from the atmosphere. Given that coal-fired utility plants are the largest source of human-caused mercury emissions in the U.S. -- about 43 tons of mercury each year -- the nexus between mercury contamination, public health risks and the energy sector is becoming clearer by the day.  Scientists are increasingly able to identify exact sources of mercury contamination, and how much those sources are emitting.  And, as the science behind mercury contamination progresses, so too must the policy options that are crafted to deal with it.  This document provides a rough overview of some recent developments in mercury research, and also provides an overview of the policy options that are available to address mercury contamination.

What is methylmercury?
Mercury is a naturally occurring element that is present throughout the environment and in plants and animals.  There are three forms of mercury -- methyl, elemental, and inorganic.  Inorganic mercury released by combustion sources and mine wastes is not a problematic emission in and of itself.  The danger comes when mercury undergoes “methylation” and is transformed to methylmercury.  Methylation is a microbial process controlled by sulfate reducing bacteria and a handful of chemical and environmental factors.   It is through methylation that atmospheric mercury becomes a problem for ecosystems.  Methylmercury is the most toxic and bioaccumulative form of mercury, and is responsible for most mercury-related concerns today.

Where is methylmercury coming from, and how much is out there?

Part of the problem with 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 by the USGS in the Everglades 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. 

“Old” vs. “New” mercury

Findings have also contradicted the assumption that "old" mercury (released 50-100 years ago) that currently exists in soils and sediments of ecosystems could continue to actively cycle in the environment and fuel the current mercury problem.  "New" mercury from contemporary emissions is more active than old mercury in the environment, and thus more responsible for driving methylmercury production and bioaccumulation.  That is to say, 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 highly transferable to the policy world, where much debate over mercury regulations centers around 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 standard, it seems clear that policy options ought to be aimed at shorter rather than long-term reduction timelines.

How does methylmercury impact public health?

A mounting body of evidence shows that mercury is a powerful neurotoxin that poses significant threats to public health.  According to EPA, high doses of mercury can cause tremors, inability to walk, 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 estimates that more than 60,000 U.S. babies born each year are at risk for neurodevelopmental effects of 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.  Where 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 resultant 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.  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 Environmental Protection Agency.

What have we done about methylmercury?

The regulation of mercury has historically been a collective effort rather than one cohesive set of regulations.  Mercury controls occur on both the state and federal level and are managed by multiple agencies.  For example, on the federal level, mercury contamination is monitored by the US EPA, the FDA (Food and Drug Administration, and OSHA (Occupational Safety & Health Administration).  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 that is 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 authority in 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 under the strictest possible conditions. However, a special provision was included in Section 112 for powerplants, requiring EPA to study the public health effects of air toxic emissions from utility 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, it 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.  The EPA continued research and 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 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

What will Congress do about mercury?

Congress has attempted to address mercury pollution by including it in “multipollutant” bills that target H_g (mercury), NO_x (nitrogen oxides), SO₂ (sulfur dioxide) and, depending on the bill, CO₂ (carbon dioxide).  Two of three legislative proposals that were proposed into the 107^th Congress capping pollution from electricity generators – President Bush's Clear Skies Initiative and Sen. Jim Jeffords’ (R-VT) bill - have been reintroduced in the 108th Congress with updated time tables and some other new features.  A third multipollutant bill (S. 843) has also been reintroduced by Sen. Thomas 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. Leahy’s (D-VT) mercury-only bill, S. 484, currently being reviewed by the Senate Committee on Environment and Public Works.

Clear Skies Act 

Clear Skies Act (S. 485, H.R. 999) would establish federally enforceable emissions limits ("caps") for NO_x, 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.  It would also institute an emissions trading system that would allow power plants to buy and sell pollution credits among each other, so long as they were meeting emission standards.

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

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: H_g, NO_x, SO_x, and CO₂ (carbon dioxide).  It would do so on a much shorter time frame than the Clear Skies act, 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 by 90 percent from 1999 levels by 2008.  Unlike Clear Skies, it would not allow powerplants to trade mercury emission allowances with each other.

As a point of comparison, S. 366 proposes to reduce by 2008 the annual national emissions of mercury to not more than 5 tons; Clear Skies proposes to set a cap of 15 tons by 2018.  S. 366 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 original Clean Air Act requirements enacted more than 30 years ago.

 Mercury control and cost-saving opportunities?

Mercury regulations need not be a money-losing venture for electricity producers.  An October 2001 study by the Energy Department's Energy Information Administration (EIA), at the request of Sen. Jeffords and Sen. Lieberman, projected savings to U.S. consumers and businesses to be $16 billion under the Clean Power Act by 2010 in comparison with a business-as-usual approach.  A majority of the savings come from increasing efficiency through energy-saving measures. According to EIA, by 2020, savings would reach more than $40 billion. With more aggressive energy savings measures, EIA approximated net savings at $27 billion by 2010, and $60 billion in 2020.

The EIA study also compared the Clean Power Act to a hypothetical three-pollutant approach, similar to the Administration’s Clear Skies proposal, and found that 2010 electricity costs would be $20 to $30 billion lower under the more comprehensive, four-pollutant strategy.