I suppose we should go to the source on the recent mercury scare. Here’s the abstract to the study, Mercury from chlor-alkali plants: measured concentrations in food product sugar:
Mercury cell chlor-alkali products are used to produce thousands of other products including food ingredients such as citric acid, sodium benzoate, and high fructose corn syrup. High fructose corn syrup is used in food products to enhance shelf life. A pilot study was conducted to determine if high fructose corn syrup contains mercury, a toxic metal historically used as an anti-microbial. High fructose corn syrup samples were collected from three different manufacturers and analyzed for total mercury. The samples were found to contain levels of mercury ranging from below a detection limit of 0.005 to 0.570 micrograms mercury per gram of high fructose corn syrup. Average daily consumption of high fructose corn syrup is about 50 grams per person in the United States. With respect to total mercury exposure, it may be necessary to account for this source of mercury in the diet of children and sensitive populations.
I found this background factoid — from the full study (PDF) — interesting:
Chlorine and caustic soda are produced at chlor-alkali plants using mercury cells or the increasingly popular membrane technology that is mercury free and more energyefficient. Worldwide there are approximately fifty mercury cell chlor-alkali plants in operation. Of those there are eight in the United States. In 2003 the EPA reported in the Federal Register that on average approximately seven tons of mercury were missing from each plant in the year 2000.
The actual results:
Mercury was detected in nine of the twenty samples analyzed (Table 1). Of ten samples from manufacturer “A”, nine were below the 0.005 ?g mercury/g sample detection limit with the sole exception being a sample that was 0.012 ?g mercury/g HFCS. Of the remaining ten samples from two other manufacturers, two were below the detection limit and the mercury content of the other eight samples ranged from 0.065 ?g to 0.570 ?g mercury/g HFCS (Table 1).Mercury was not detected in eleven out of twenty HFCS samples analyzed (detection limit 0.005 ?g mercury/g). A single manufacturer produced nine of these eleven samples. These samples were likely manufactured using caustic soda produced by a membrane chlor-alkali plant which does not use mercury in its manufacturing process.
Eight of the nine HFCS samples exhibiting mercury levels between 0.065 ?g to 0.570 ?g mercury/g HFCS were produced by the other two manufacturers. This could indicate the use of mercury grade caustic soda or hydrochloric acid in the manufacturing processes used by these two manufacturers.
Another interesting factoid:
Results of a recent study of dietary fructose consumption among US children and adults indicate that fructose consumption by Americans represents ten percent (10%) of calories consumed in a 24-hour period. Seventy four percent (74%) of this fructose came from foods and beverages other than fruits and vegetables.
So, how much mercury are consumers consuming?
With the reported average daily consumption of 49.8 g HFCS per person, however, and our finding of mercury in the range of 0.00 to 0.570 ?g mercury/g HFCS, we can estimate that the potential average daily total mercury exposure from HFCS could range from zero to 28.4 ?g mercury.
Is that bad?
This range can be compared to the range of total mercury exposure from dental amalgam in children reported by Health Canada. In the report issued by Canada, daily estimates of total mercury exposure from dental amalgam in children ages 3-19 ranged on average from 0.79 to 1.91 ?g mercury. Canada and other countries do not recommend the use of mercury amalgam in pregnant women or children.
That’s an odd benchmark, isn’t it? The paper then goes on to mention the neural toxicity of methylmercury, which doesn’t necessarily seem applicable; it’s the form of mercury consumers absorb from eating tuna fish.
As Wikipedia points out, elemental mercury is poorly absorbed by ingestion and skin contact; less than 0.01% of ingested mercury is absorbed through the gastrointestinal tract. Even mercury salts, which dissolve better in water and thus get absorbed more by the GI tract, inflict little neurological damage without continuous or heavy exposure.
It’s the organic mercury compounds that can be frighteningly lethal. Famously, dimethylmercury, is so toxic that even a few microliters spilled on the skin, or even a latex glove, can cause death.
Anyway, if a mercury scare drops HFCS consumption, I suppose that’s an inadvertent public health boon.