 CONSENSUS
STATEMENT ON METHYLMERCURY AND PUBLIC HEALTH – National
and Statewide Endorsers (California)
Alameda County Board of Supervisor's Health
Committee • Alameda County Environmental Health Department
• Alameda County Persistent Bioaccumlative Toxicants
Committee • Alameda County Public Health Department
• American Academy of Pediatrics • American Association
on Mental Retardation • American College of Preventive
Medicine • American Nurses Association • American
Public Health Association • American Association on
Mental Retardation • The Arc of the United States •
Association of Labor Assistants and Childbirth Educators •
Association of Reproductive Health Professionals • Bayview
Hunters Point Community Advocates • Breast Cancer Action
• The Breast Cancer Fund • California Communities
Against Toxics • Catholic Healthcare West • Center
for Environmental Health • Children’s Environmental
Health Network • Clean Water Action • Commonweal
• Community Toolbox for Children's Environmental Health
• Department of Pediatrics, John Muir Medical Center
• East Bay Learning Disabilities Association •
Environmental Health Fund • EnviroSpec • Health
Care Without Harm • Health Link • Healthy Buildings
Network • Healthy Children Organizing Project •
Hesperian Foundation • Institute for Children's Environmental
Health/Learning and Developmental Disabilities Initiative
• Institute for Agriculture and Trade Policy •
Institute for Children’s Environmental Health •
Institute for Neurotoxicology and Neurodevelopmental Disorders
• Institute for a Sustainable Future • International
Indian Treaty Council • Kids Eat Great, Inc. •
Learning Disabilities Association • Literacy for Environmental
Justice • Ma’at Youth Academy • Mount Sinai
Center for Children's Health and the Environment • National
Association of County and City Health Officials • National
Latina Health Organization • Physicians for Social Responsibility
• San Francisco Medical Society • Saratoga Foundation
for Women Worldwide, Inc • Southern California Public
Health Association • Women’s Voices for the Earth
As organizations representing medical and public health
professionals, women, and advocates of children and families,
we are concerned that the American public is not adequately
protected from exposure to mercury in the environment. We
call for immediate actions to protect the general public
and vulnerable populations such as pregnant women and children,
through stronger regulations to curb mercury emissions at
their source, and through improved fish consumption guidance
to reduce exposures.
I. Our Organizations Are Concerned About the Human Health
Toll from Mercury Pollution.
Mercury threatens human health and child development. Scientific
findings indicate that mercury is a significant threat to
the fetus, infants, and young children. Exposure to methylmercury,
the highly toxic form of organic mercury found in our environment
and food, may adversely affect reproduction[1]
and a variety of organ systems, including the cardiovascular
system[2,3], and, in particular,
the brain and central nervous system.[4]
The developing brain is more susceptible to methylmercury
exposure than are adult brains, and is most sensitive while
in utero.[5] Methylmercury crosses the placenta
easily and readily penetrates the fetal brain.[6]
It is also secreted in breast milk, although the contribution
of methylmercury exposure through lactation is not yet fully
understood.[7]
High dose exposures to methylmercury during fetal development
can result in low birth weight, small head circumference,
severe mental retardation, cerebral palsy, deafness, blindness,
and seizures.[8] Recent epidemiological studies
have shown that children exposed to moderate or low levels
of mercury before birth may also experience neurological and
development impairment. Outcomes may include delayed walking,
delayed speech, and decreased performance on tests of attention,
fine motor function, language, visual-spatial abilities, and
memory.[9,10,11]
The U.S. Environmental Protection Agency (EPA) has derived
a “safe” level for mercury in the human body of
5.8 micrograms per liter (_g/L) of blood, and a reference
dose (RfD) of 0.1 _g per kilogram of body weight per day.[12]
The National Academy of Sciences (NAS) has endorsed EPA’s
RfD, calling it a “scientifically appropriate level
for the protection of public health.” [13]
The American public is exposed to methylmercury at unacceptable
levels. Mercury released from various industrial sources eventually
deposits in water bodies, where it is converted to methylmercury
through microbial action and accumulates in many edible fish
species. Most Americans’ exposure to methylmercury comes
through contaminated fish. Virtually all freshwater and ocean
fish and shellfish are contaminated to varying degrees, and
the range of methylmercury levels commonly found in these
foods include some that pose a health risk to the public.
[14]
The Centers for Disease Control and Prevention (CDC) found
in January 2003 that nearly eight percent of women of child
bearing ages (16 to 49) are exposed to levels of mercury that
exceed the EPA RfD, considered safe for a fetus.[15]
A more recent analysis by EPA scientists raised that estimate
to more than 15% of women, based on peer-reviewed studies
showing that cord blood concentrates mercury at significantly
higher levels than maternal blood.[16] Using
2000 census figures to extrapolate across the entire U.S.
population, this could mean that as many as 630,000 newborns
each year are at risk of serious congenital neurological and
developmental impairment.
The American public is not adequately protected from mercury
pollution. Available data suggest that human activities have
increased levels of mercury in the atmosphere by roughly a
factor of 3, average deposition rates by a factor of 1.5 to
3 and deposition near industrial areas by a factor of 2 to
10.[17] Major identified sources of mercury
pollution in the United States include coal-fired power plants,
industrial boilers, municipal and medical waste incinerators,
and chlorine manufacturing (chlor-alkali) facilities.[18]
While mercury emissions from various sources may be transported
long distances in the atmosphere, local mercury sources play
an important role in local pollution. Draft EPA modeling indicates
that at mercury “hotspots” within the United States
(locations where mercury deposition is highest), local emission
sources within a state can be the dominant source of deposition.
In addition, a recent 10-year study by the state of Florida
points to the importance of local mercury pollution sources
and the feasibility of measures to protect public health.
In that study, strict emission limits applied to incinerators
in south Florida were found to produce emissions reductions
of 99% and corresponding reductions in mercury levels in Everglades
fish and wildlife of 60%.[19]
As states have recognized the problem posed by mercury in
their waters and developed improved monitoring programs, public
health warnings designed to minimize the public’s exposure
to methylmercury-contaminated fish and shellfish have increased
dramatically. State-level fish consumption advisories for
mercury are up from 899 in 1993 to 2,140 in 2002[20]
(an increase of 138 percent in total); more than 12 million
lake acres and 473,000 river miles in 44 states were under
advisory for methylmercury in 2002. At the federal level,
however, consumption guidance from EPA and the Food and Drug
Administration (FDA) has been fragmented, incomplete, and
sometimes contradictory. In July 2002, and again in December
2003, FDA’s own Food Advisory Committee recommended
that existing federal guidance be strengthened to sufficiently
protect public health and vulnerable populations.[21]
II. We Call on Federal, State, and Tribal Leaders to Do
More to Protect Public Health from Mercury.
In light of the serious public health threat posed by exposure
to methylmercury, particularly to the fetus, infant, and young
child, and acknowledging the scientific consensus which supports
major reductions in industrial mercury emissions as quickly
as possible, we call for immediate actions to remediate the
threat of mercury exposure. Therefore, policy makers at all
levels should:
1. Treat mercury emissions from all anthropogenic sources
as “hazardous,” and rapidly implement regulations
aimed at attaining the maximum achievable emissions reductions;
2. Employ protective and uniform emission limits for anthropogenic
mercury sources in all communities, with no trading of mercury
emissions among sources;
3. Develop comprehensive consumption guidelines for mercury
in fish and seafood that is scientifically based and aimed
at ensuring that 98% or more of the population — particularly
women of reproductive age and children — is within
EPA’s “safe” level of methylmercury exposure;
and
4. Cooperate internationally to reduce the global problem
of mercury contamination by addressing mercury sources in
all countries.
1 Choy CM, Lam CW, Cheung
LT, Briton-Jones CM, Cheung LP, Haines CJ. Infertility, blood
mercury concentrations and dietary seafood consumption: a
case-control study. BJOG: an International Journal of Obstetrics
and Gynecology. 2002:109:1121-5.
2 Yoshizawa K, Rimm
E B, Morris JS, Spate VL, Hsieh CC, Spiegelman D, Stampfer
MJ, Willett WC, 2003. Mercury and the risk of coronary heart
disease in men, N Engl J Med. 2002: 28;347(22):1755-60.
3 Gualler E, et. al,
Mercury, fish oils, and the risk of myocardial infarction,
N Engl J Med. 2002:347:1747-54.
4 Sanfeliu C, Sebastia
J, Cristofol R, Rodriguez-Farre E. Neurotoxicity of organomercurial
compounds. Neurotox Res. 2003;5(4):283-305.
5 Agency for Toxic
Substances and Disease Registry (ATSDR). 1999. Toxicological
profile for mercury. Atlanta, GA: U.S. Department of Health
and Human Services, Public Health Service. http://www.atsdr.cdc.gov/toxprofiles/tp46.html
6 Myers GJ, Davidson
PW. Prenatal methylmercury exposure and children: neurologic,
developmental, and behavioral research. Environ Health Perspect.
1998 Jun;106 Suppl 3:841-7.
7 Sakamoto M, et al.
Declining risk of methylmercury exposure to infants during
lactation. Environ Res. 2002 Nov;90(3):185-9.
8 Kondo K. Congenital
Minamata disease: warnings from Japan’s experience.
J Child Neurol. 2000 Jul;15(7):458-64.
9 Grandjean, P., et.
al. Cognitive deficit in 7-year-old children with prenatal
exposure to methylmercury, Neurotoxicology and Teratology,
1997: 19(6):417-428.
10 Grandjean, P.,
et al., Methylmercury neurotoxicity in Amazonian children
downstream from gold mining, Environmental Health Perspectives.
1999:107(7):587-591.
11 Steuerwald, U,
et al. Maternal seafood diet, methylmercury exposure, and
neonatal neurologic function. J Pediatr. 2000 May;136(5):599-605.
12 U.S. EPA, 1997a.
Mercury Study Report to Congress, Volume V: Health Effects
Of Mercury And Mercury Compounds. EPA-452/R-97-007.
13 Committee on the
Toxicological Effects of Methylmercury, Board on Environmental
Studies and Toxicology, National Research Council, National
Academy of Sciences. Toxicological Effects of Methylmercury.
2000.
14 U. S. Food and
Drug Administration, Center for Food Safety and Applied Nutrition,
Office of Seafood. Mercury Levels in Seafood Species. May
2001. http://www.cfsan.fda.gov/~frf/sea-mehg.html.
15 Schober SE, et
al. Blood mercury levels in US children and women of childbearing
age, 1999-2000. JAMA 2003:289(13);1667-1674.
16 Mahaffey KR. Methylmercury:
Epidemiology Update. Slide presentation given at the National
Forum on Contaminants in Fish. San Diego, CA. January 26,
2004. Accessed online March 1, 2004. http://www.epa.gov/waterscience/fish/forum/2004/presentations/monday/mahaffey.pdf.
17 From UNEP Global
Assessment of Mercury, 2003. http://www.chem.unep.ch/mercury/Report/Key-findings.htm
18 U.S. EPA, 1997a.
Mercury Study Report to Congress, Volume II: An Inventory
of Anthropogenic Mercury Emissions in the United States. EPA-452/R-97-004.
19 Florida Department
of Environmental Protection. Integrating Atmospheric Mercury
Deposition and Aquatic Cycling in the Florida Everglades:
An approach for conducting a Total Maximum Daily Load analysis
for an atmospherically derived pollutant, Integrated Summary,
Final Report. October 2003. http://www.floridadep.org/labs/mercury/index.htm.
20 U.S. EPA, Office
of Water. Update: National Listing of Fish and Wildlife Advisories.
May 2003. EPA-823-F-03-003. http://www.epa.gov/ost/fish
21 U. S. Food and
Drug Administration. Minutes of the FDA Food Advisory Committee
Meeting on Methylmercury. July 23-25, 2002. http://www.fda.gov/ohrms/dockets/ac/02/minutes/3872m1.pdf.
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