While anti-vaccine researchers are being charged with ethical lapses, the mercury issue marches on

Dr. Mercola links to an public service announcement about the presence of mercury in vaccines. This PSA(Public Service Announcement) contains one tidbit that I haven’t heard yet: that the EPA suggests that the amount of mercury still present in vaccines is safe only if you weigh over 500 pounds. Is there a source for this information?

Update: So, I’ve dug a little deeper. Here’s what I’ve found:

  • The EPA’s webpage on human exposure of mercury is here.
  • I found the following statement in mercury’s tox profile:

EPA and FDA have set a limit of 2 parts inorganic mercury per billion (ppb) parts of water in drinking water. EPA is in the process of revising the Water Quality Criteria for mercury. EPA currently recommends that the level of inorganic mercury in rivers, lakes, and streams be no more than 144 parts mercury per trillion (ppt) parts of water to protect human health (1 ppt is a thousand times less than 1 part per billion, or ppb). EPA has determined that a daily exposure (for an adult of average weight) to inorganic mercury in drinking water at a level up to 2 ppb is not likely to cause any significant adverse health effects. FDA has set a maximum permissible level of 1 part of methylmercury in a million parts (ppm) of seafood products sold through interstate commerce (1 ppm is a thousand times more than 1 ppb). FDA may seize shipments of fish and shellfish containing more than 1 ppm of methylmercury, and may seize treated seed grain containing more than 1 ppm of mercury.

  • John Hopkin’s University (Bloomberg School of Public Health) maintains a vaccine safety site. They included a table of thimerosal concentrations.
  • The FDA maintains its own thimerosal page. Of note, according to a 1999 review, “…, depending on the vaccine formulations used and the weight of
    the infant, some infants could have been exposed to cumulative levels
    of mercury during the first six months of life that exceeded EPA
    recommended guidelines for safe intake of methylmercury.” (The Hg-containing metabolite of thimerosal is ethylmercury.)

If you do the math on the 0.1µg/kg/day reference dose set forth by the EPA and compare it to the tables on the FDA page and Vaccinesafety.edu pages, at least for the pediatric vaccines, you don’t get 500 pounds. The worst case scenario that I found was the Fluvirin® that was before 9/28/2001 and Fluzone® flu vaccine that was before 12/23/2004, both of which contained 25 µg of thimerosal in a 0.5 mL dose before newer versions were approved. This does work out to a little over 550 pounds (25 µg / 0.1 µg/kg =250kg = 551 lbs), and this may very well be the source of the 500 pound message; however, the vaccines have been replaced with one with one less than 1 µg/0.5 mL dose or even thimerosal-free versions.

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