The Mercury Mystery: Is it Still Lacing Our High Fructose Corn Syrup?

by Ellen

I’m perplexed. I’ve been trying to track down the source of some mercury and need help finding it. Is mercury still contaminating some sources of high fructose corn syrup?  The game is afoot!

In January, 2009, The Institute for Agriculture and Trade Policy (IATP) released its report, “Not So Sweet: Missing Mercury and High Fructose Corn Syrup,” which listed the mercury content of 55 kid-friendly foods. For the report, IATP researchers headed to supermarket shelves to collect a “snapshot” sample of several common brand-name foods containing high levels of high fructose corn syrup (HFCS). They tested the food samples for mercury and got some shocking results:  Almost one third of the foods tested contained mercury, with Quaker Oatmeal to Go containing the highest amount.

For a look at the IATP list of 55 foods tested and their mercury levels, click here. Mercury was found in chocolate milk (See! That’s why I’m crazy to get it out of school lunches!), barbecue sauce, ketchup, cereal bars, jelly, yogurt, and more. On first analysis, 17 of 55 sampled foods contained detectable levels of mercury; after re-testing some of the negative samples, the contaminated number rose to 20. HFCS was the suspected source of the mercury contamination of these foods and beverages.

Why did IATP researchers target HFCS-containing foods?

One of the IATP report’s authors, Dr. David Wallinga, was also co-author of a scientific study published at almost the same time, in the peer-reviewed journal Environmental Health: “Mercury from chlor-alkali plants: measured concentrations in food product sugar”.  The Environmental Health study was spearheaded by Renee Dufault, an environmental investigator for the Food and Drug Administration at that time. This examination of commercial high fructose corn syrup samples found nearly 50 percent of them to be contaminated with mercury. (Although the samples were collected in 2005, the study wasn’t published until four years later, after Dufault retired from the FDA.)

Bottom line: The FDA has known about mercury contamination in HFCS since 2005.

How might mercury get into high fructose corn syrup?

Caustic soda (aka hydrogen peroxide) is used to separate corn starch from the kernel in the initial stages of HFCS production.  The pH is then tweaked with hydrochloric acid and caustic soda during the production process.  Caustic soda and hydrochloric acid are produced in chlorine (chlor-alkali) plants, some of which still use outdated mercury cell technology.  The mercury from these plants can contaminate the plant’s products and the wider environment.

The Corn Refiners Association issued a statement calling the Environmental Health results outdated. The CRA reported that it has used mercury-free caustic soda and hydrochloric acid for years. Where, then, does the mercury come from? It would be helpful to know the source of all the food grade chemicals used in the manufacture of HFCS.

Why worry about small amounts of mercury?

The mercury detected by both the IATP and Environmental Health studies is “total mercury,” meaning it can be any combination of organic, inorganic or metallic mercury.  The FDA is most concerned with organic mercury, especially methylmercury.  However, mercury in any form is toxic. Mercury is known to cause neurological and behavioral problems while efficiently lowering IQ. (See Dufault’s other study here.) Mercury affects our brains, and is probably most toxic to developing brains. While the FDA has set limits on the amount of methylmercury from seafood that we should eat, it has yet to determine a “safe” limit for total mercury consumption.

From the Environmental Health article:

Mercury in any form – either as water-soluble inorganic salt, a lipid-soluble organic mercury compound, or as metallic mercury- is an extremely potent neurological toxin [23]. Organic mercury compounds such as methylmercury that are fat-soluble and readily cross the blood brain barrier are especially damaging to developing nervous tissues [24,25]. For example, prenatal exposure as low as 10 mg/kg methylmercury, as measured in maternal hair growing during pregnancy, may adversely affect the development of the fetal brain [25,26]. Confounding associations and concerns with various stages of brain development related to cumulative early life exposure to mercury include the following sources of mercury: maternal fish consumption during pregnancy, the thimerosal (sodium ethylmercurithiosalicylate, approximately 49% mercury weight) content of certain vaccines and dental amalgam [27].

Why can’t we identify the manufacturers who use mercury?

In the Environmental Health study, commercial HFCS was analyzed from three manufacturers identified simply as “Manufacturer A, B, and C.” (see table 1) Unfortunately, we can’t approach those same manufacturers and ask whether they now use mercury-free food-grade caustic soda and hydrochloric acid. Nor can we ask them if they test their HFCS for mercury. From Dufault, et al.,

With key aspects of the HFCS manufacturing process considered proprietary information, we could not confirm the composition of the raw materials used by the individual HFCS manufacturers and the subsequent source of the mercury… Clearly the sample size of this preliminary trial is too small but there was no support to collect additional samples for analyses. When university researchers outside of the government attempted to obtain additional HFCS samples direct from the manufacturer they were unable to get them.


…With 45% of the HFCS samples containing mercury in this small study, it would be prudent and perhaps essential for public health that additional research be conducted by the FDA or some other public health agency to determine if products containing HFCS also contain mercury. In 2004, several member states of the European Union reported finding mercury concentrations in beverages, cereals and bakery ware, and sweeteners [14] – all of which may contain HFCS. FDA does not currently have a mercury surveillance program for food ingredients such as added sugars or preservatives manufactured with mercury grade chlor-alkali products.

What’s being done to protect the public from mercury in HFCS?

Not much. While the FDA does monitor some foods for mercury, they don’t specifically test foods containing high fructose corn syrup.

The Corn Refiners Association has stated that it no longer uses mercury-grade caustic soda to produce HFCS, but according to Dufault et al, this statement has not been independently verified.

Back in 2007, then Senator Obama introduced legislation to phase out mercury technology in chlorine plants (S.1818 – Missing Mercury in Manufacturing Monitoring and Mitigation Act), which died on the Senate floor. A subsequent bill (H.R. 2190) was introduced in 2009, but hasn’t been voted on yet.  (You can let your representative know how you feel by commenting at

Two weeks ago I wrote to the FDA to ask what steps are being taken to protect the public from mercury-laced HFCS, but I have yet to receive a response.

So, here are some puzzle pieces:

  • Mercury was found in some domestic sources of HFCS as late as 2005.
  • According to the January, 2009 IATP report, there were four chlor-alkali plants in the US that still used mercury cell technology AND
  • Mercury cell technology probably still existed in December, 2009, since legislation to phase out mercury chlor-alkali plants was placed on the House of Representatives calendar at that time.
  • 30% of foods sampled by IATP in the fall of 2008 contained measurable mercury.
  • The Corn Refiners Association says it has used mercury-free caustic soda “for years.”  Has the CRA used no mercury-grade ingredients??
  • The food ingredients citric acid and sodium benzoate may also be manufactured from mercury-grade chemicals produced in mercury cell chlor-alkali plants.

Before we solve the mercury puzzle, we can:

  • Cut high fructose corn syrup from our diets. Even if all US sources of HFCS become mercury-free, many foods can still contain HFCS from Europe, which may be contaminated. (In 2005, only 40 percent of European chlorine was produced using mercury-free technology.)
  • Inspect future ingredients labels for “corn sugar,” if the Food and Drug Administration allows the new name for high fructose corn syrup.
  • Remove chocolate milk from school lunches! (Even if it doesn’t contain mercury, there’s a good chance it contains GMOs (in HFCS), recombinant growth hormone, and/or nonfat milk powder.)
  • Push corn processors to use food-grade chemicals produced in plants that don’t use mercury cell technology.
  • Speak up. Ask the FDA and Congress to require all chlorine factories to ditch hazardous mercury cell technology and upgrade to modern manufacturing methods.  Ask your Representatives and Senators to support the Mercury Pollution Reduction Act (H.R. 2190/S. 1428). You can also give a “thumbs up” and leave comments on
  • See which organizations support or oppose legislation to reduce mercury pollution!

The good news?

Switching from mercury cell technology to membrane technology will save energy. It’s good for the environment in another way, too: There won’t be any “missing mercury” released into the environment to contaminate our air, fish, and more.

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Photo Credits:  grahamc99 and MU_314947 on flickr


1) Dufault R, LeBlanc B, Schnoll R, et al. “Mercury from chlor-alkali plants: measured concentrations in food product sugar.” Environmental Health. 2009, 8: 2. doi:10.1186/1476-069X-8-2

2) Wallinga, D., Sorensen, J., Mottl, P., and Yablon, B., “Not So Sweet: Missing Mercury in High Fructose Corn Syrup.” The Institute for Agriculture and Trade Policy, 2009.

3)  Dufault, R., Schnoll, R., Lukiw, W., LeBlanc, B., Cornett, C., Patrick, L., Wallinga, D., Gilbert, S., and Crider, R. “Mercury exposure, nutritional deficiencies and metabolic disruptions may affect learning in children.”  Behavioral and Brain Functions 2009, 5:44doi:10.1186/1744-9081-5-44

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Jack November 4, 2010 at 11:21 am

My recollection is that years ago forms of mercury were used as fungicides in plant seeds, including grains. So I checked Google by entering the search ‘mercury as fungicide in plant seeds’ and what I found is verification that at least in the past (not all articles found in the search are dated) a source of mercury in HFCS may be the corn from which it is extracted.

Ellen November 4, 2010 at 12:54 pm

Great point! It is very hard to track down current information about laws concerning the use of fungicides that contain mercury.
Corn crops could also be contaminated from atmospheric mercury (from coal-fired plants) that finds its way into the soil from rain or water used for irrigation.

Jim November 4, 2010 at 11:46 am

This posting reveals information that is anything but elementary! Mercury is our Moriarity and we have to take it down Reichenbach Falls!

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