Mercury: Pregnant Women Should Limit Mercury Consumption

Much of the world’s fish supply is contaminated with methylmercury, a chemical produced by industrial processes and by natural events such as volcanic explosions and forest fires.  In adults, mercury is rapidly absorbed into the bloodstream from the stomach and the intestine; it then readily enters the brain, where it accumulates and begins wreaking its neurotoxic effects.  Click on Mad Fish Disease to read more about the effects of too much mercury on some fetuses.

From The Toxic Sandbox (2007) by Libby McDonald; pages 44 – 45:

The Bad News

• A child is dangerously exposed to mercury in utero when a mother eats fish or seafood with a high level of mercury.
• Canned tuna and many kinds of sushi contain mercury.
• Prenatal exposure to mercury is much more powerful in causing intellectual and behavioral problems than exposure after a child is born.
• The CDC estimates that 16% of US women have blood mercury levels high enough to double their risk of giving birth to children with learning disabilities and / or neurological problems.
• No one knows for sure what level mercury exposure in utero leads to demonstrable, lifelong harm.
• Mercury has been linked to:
  • Memory deficits
  • Shortened attention span
  • Inability to concentrate
  • Lack of coordination
  • Problems learning language
  • Poor vision and hearing
  • Loss of IQ points
  • Mental retardation
  • Seizures
  • Depression
  • Bipolar disorder

The Good News

• You can keep your children safe from high levels of mercury exposure simply by avoiding fish altogether, or by referring to lists of low-mercury fish.  (Please keep in mind that there are studies showing that low levels of seafood consumption during pregnancy were associated with increased risk of low verbal IQ, social and communication problems, and poor fine-motor skills in children six months to eight years of age.)
• Many studies have shown that ethyl mercury — used as an ingredient in many childhood vaccines until 2001 — is not harmful, and in particular is not linked to the rise in autism.
• Today vaccines contain little to no ethyl mercury.

Women can protect their future unborn children by reducing their exposure to mercury six to twelve months before conception.

– The Toxic Sandbox (2007) by Libby McDonald; page 50

By analyzing studies of communities poisoned by mercury, the EPA has determined that mercury above 5.8 parts per billion in the bloodstream of a woman of childbearing age can harm babies int he womb.  However, if a pregnant woman eats fish with a high mercury concentration, the metal is pumped across to the fetus and becomes concentrated in the baby’s umbilical cord blood, significantly upping the dose of mercury in fetal blood above the mother’s own mercury blood level.  For this reason, may researchers believe the EPA’s threshold may not be high enough to protect developing babies in utero.

The EPA’s questionable mercury threshold is reminiscent of the CDC’s disputed lead threshold.  In the 1960s the CDC determined that anything under sixty micrograms per deciliter of lead kept children out of harm’s way.  Researchers now know that even a count of two effectively hammers away at the developing brain, shaving off IQ points.  While researchers have been examining lead toxicity for a hundred years, mercury has only been studied for fifty.  Only time will tell whether the EPA’s current methyl mercury threshold level is appropriate.

– The Toxic Sandbox (2007) by Libby McDonald; pages 50 – 51

The National Academy of Sciences estimates that mercury exposure in the womb is responsible for sixty thousand babies born in this country each year with neurological damage and mental impairments.  The Learning Disabilities Association of America (LDA), the National Education Association (NEA), and the Arc of the United States all say mercury pollution is one of the biggest culprits in the rising tide of learning deficits.

– The Toxic Sandbox (2007) by Libby McDonald; pages 51 – 52