Environmental Engineering Reference
In-Depth Information
CHAPTER 14
Mercury Exposure in Vulnerable Populations
Guidelines for Fish Consumption
JOHN DELLINGER, MATTHEW DELLINGER,
and JENNIFER S. YAUCK
through the contaminated fi sh. In all, several thousand
people were reportedly affected by what came to be known
as Minamata disease (Ministry of the Environment, 2002).
More than 60 years later, mercury-contaminated fi sh
still pose a threat to human health. According to the U.S.
Environmental Protection Agency (USEPA) and the U.S.
Food and Drug Administration (USFDA), nearly all fi sh
contain trace amounts of mercury (USEPA and USFDA,
2004). Fish consumption, in fact, is the main route by
which humans are exposed to the metal, typically in a
highly absorbable form known as methylmercury (Agency
for Toxic Substances and Disease Registry [ATSDR], 1999).
However, outright poisonings from exposure to excessive
levels of mercury in fi sh—like the poisonings that occurred
in Minamata—are rare. More commonly, human exposure
to mercury in fi sh is long term in nature and occurs at rela-
tively low levels.
In an effort to safeguard human health, international,
national, state, local, and tribal agencies establish guide-
lines for fi sh consumption. However, developing such
guidelines can be a challenging task. This is because fi sh,
although it contains mercury, is also a highly nutritious
food. Fish consumption, therefore, has both risks and ben-
efi ts. Moreover, in populations like Minamata's, where fi sh
is a dietary staple, restricting or removing fi sh from the
diet can introduce health risks by diminishing the intake
of critical nutrients. Ideal fi sh-consumption guidelines,
therefore, attempt to balance the health risks of mercury
exposure against the health risks of absent or diminished
dietary benefi ts.
RISKS OF MERCURY IN FISH
BENEFITS OF NUTRIENTS IN FISH
POTENTIAL COMPLICATING FACTORS
GUIDELINES FOR FISH CONSUMPTION
Fish Advisories in the United States
Developing Fish Advisories
Mercury Advisories
VULNERABLE POPULATIONS
Recognizing Variations in Risks and Benefi ts
Defi ning Vulnerable Populations
Unusually Susceptible or Sensitive Populations
Populations with Potentially High Mercury Exposures
COMMUNICATING RISKS AND BENEFITS
The Importance of Communication
Community-Based Participatory Research
CONCLUSION
In the 1950s, a mysterious epidemic hit the Japanese fi sh-
ing village of Minamata. An unusual number of residents
began to exhibit odd behaviors, such as slurring their
speech, stumbling, or trembling uncontrollably. Hearing
and vision impairments developed in some, and paralysis
in others. The malady even affected newborn babies, some
of whom were born with physical deformities, cerebral
palsy, or mental retardation.
An investigation eventually linked the village's strange
outbreak of health problems to a pollutant in Minamata
Bay: mercury. For years, a local chemical plant had dis-
charged organic mercury into the bay's waters, where the
pollutant moved up the food chain and eventually accu-
mulated in fi sh. The villagers, whose diet consisted largely
of seafood, were exposed to excessive amounts of mercury
Risks of Mercury in Fish
Prior to the Minamata disaster, little was known about the
human health effects of mercury. Today, it is well estab-
lished that high-dose mercury poisonings in adults can
