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Many commonly used substances like and fertility problems. These toxic effects have Mercury
ethanol (alcoholic beverages), herbicides and been documented by the U.S. Department of
even saunas can cause birth defects. Viral in- Health and Human Services’ Agency for Toxic is one of
fections, radiation, drugs, maternal disease or Substances and Disease Registry (ATSDR). The the most
metabolic conditions (diabetes, hypothyroid), extreme toxicity of mercury can be seen from insidious and
heavy metals in the environment, malnutrition documented effects on wildlife at very low lev-
or nutrient deficiencies and goitrogens can also els of exposure. Because of its extreme toxicity, dangerous
be major factors. only one-half gram of mercury is required to teratogens on
3
Mercury (Hg) is a major teratogen, consid- contaminate the ecosystem and fish of a ten-acre earth because
ered one of the most toxic substances on earth lake to the extent that a health warning would
and a serious global pollutant. Natural emissions be issued by the government not to eat the fish. 5 it has ready
of mercury into the air and water occur from Mercury is one of the most insidious and access to the
volcanic eruptions, through weathering of rocks, dangerous teratogens on earth because it has human body
degassing of the earth’s crust and evaporation ready access to the human body even before
of water. Man-made sources of mercury include birth, while the baby is in utero. The unborn even before
industrial pollution, burning fossil fuels (the are most at risk from the effects of mercury. birth, while
largest source of pollution), mining (gold, sil- It can be inhaled, passed through the skin or the baby is
ver), refuse incineration, cremation and factory ingested. Mercury exposure even once during a
production. Mercury is no longer mined in the pregnancy can cause harm to the unborn child’s in utero.
U.S.—most mercury today comes from mines in body and mind, while continued exposure
Spain, China, Kyrgyzstan and Algeria. Mercury causes increasingly serious defects. 5
is often used in gold mining, and many small
operators in Africa use children to separate out FISH CONSUMPTION
the gold. Paints and building materials such as The Food and Drug Administration (FDA)
roofing shingles contain mercury, which can be and Environmental Protection Agency (EPA)
released during use and disposal. Fossil fuel- recommend that women who are pregnant,
burning power plants are the largest source of breastfeeding or plan on becoming pregnant;
mercury pollution. women of childbearing age; and children con-
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Researchers have positively identified vari- sume more fish—two to three servings (eight
ous teratogens through observation, anecdotal to twelve ounces) from the “Best Choices” list
evidence, animal studies and examination of or one serving from the “Good Choices”—but
human exposures. Studies on animals have avoid seven specific fish highest in mercury.
found mercury to be extremely cytotoxic, neu- They say that children should eat one to two
rotoxic, immunotoxic and genotoxic; it is also seafood meals per week starting at age two.
an endocrine disrupter and a cause of infertility The 2017 FDA chart “Advice about Eating Fish”
FORMS AND SOURCES OF MERCURY
Mercury is a heavy metal that occurs in several basic forms: organic methylmercury (MeHg) and ethylmercury (EtHg),
and inorganic (metallic or elemental) mercury. Organic mercury is the most dangerous form of mercury to human health. 6
Historically, most of the research and concern regarding mercury’s toxic effects on humans and in particular on fetal
development has focused on MeHg, which is considered one of the six most dangerous chemicals in the environment.
7
MeHg can easily cross into the brain and body organs and is also extremely neurotoxic, much more so than inorganic
forms. MeHg is better absorbed and shows a higher mobility in the human body than inorganic mercury. Ethylmercury is
present in thiomersal, which has been used as a major preservative in vaccines. Today it is still in use in the flu vaccines
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recommended for pregnant women and children older than six months of age. 9
MeHg is found mainly through food, especially fish ingestion, although industrial pollution is also a dangerous source.
Mass poisonings affected many in Iraq when people consumed bread made from seeds sprayed with mercury. There have
been highly publicized major acute poisonings affecting many people and infants exposed through eating fish in Japan
at Minamata Bay in 1956. The Minamata disaster was caused by release of MeHg into the bay by the Chisso Chemical
Corporation. 10
SPRING 2018 Wise Traditions 41