Mercury from chlor-alkali plants: measured concentrations in food product sugar

doi:10.1186/1476-069X-8-2

Environmental Health

Volume 8

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Letter to the Editors Re: Dufault et al. in Environmental Health (2009) 8:2
Response to Chlorine Institute's Comments

Letter to the Editors Re: Dufault et al. in Environmental Health (2009) 8:2

Arthur Dungan (11 February 2009) The Chlorine Institute, Inc.

February 9, 2009

To the Editors:

While we share public concern about the safety of our food supply, we believe that you did a vast disservice to your readers and the chlor-alkali industry by publishing an article [Dufault et al. in Environmental Health (2009) 8:2] that, without any scientific evidence whatsoever, claims that chlor-alkali plants are the source of the mercury they found in samples of high fructose corn syrup and other food products. The report, “Mercury from chlor-alkali plants: measured concentrations in food product sugar,” carries nothing more than unsubstantiated, unwarranted speculation concerning a purported relationship between such plants and mercury in foods.

While the study raises important questions regarding mercury in the diet, careful evaluation is needed to survey all potential sources and exposures before characterizing a source for consumers’ potential health risk. Simple conjecture born of irresponsible science only serves to misinform and mislead the public. Moreover, deliberate misrepresentation of findings has no role in a peer-reviewed technical journal.

I urge the readers and scientific reviewers of Environmental Health to demand a higher standard of reporting and one that is consistent with research conducted using the scientific method. We are chagrined that the authors of such a study would allow such idle speculation to be prominently reported in the study’s findings. We are outraged that none of the peer reviewers pointed out this obvious speculation or called for changes.

Contrary to the authors’ speculation, it is neither physically nor chemically possible for caustic soda to be the source of the mercury levels identified in this study. The study correctly points out that most of the caustic soda produced in the United States is produced by chlor-alkali plants that do not use mercury cell technology. However, the mercury levels the authors report are some 50 times higher than what can be attributed to any trace amounts of mercury in caustic soda produced by chlor-alkali plants that do not use mercury cell technology.

Food-grade caustic soda is safe to use in the food-processing industry. Caustic soda used in food processing must meet stringent international Food Chemicals Codex standards established by the World Health Organization, Food and Agriculture Organization and international governments. Furthermore, the report fails to account for the possibility of other mercury sources. It is important to note that mercury is ubiquitous in our environment due to natural and man-made sources. For example, it is common to find measurable mercury in the soil in which we grow our food, and the U.S. Environmental Protection Agency allows up to two parts per billion in the drinking water we consume daily.

We urge the editors of Environmental Health and the authors of the study to point out as quickly as possible that they provide no scientific link connecting caustic soda to the reported levels of mercury they found in their study.

Very truly yours,

Arthur E. Dungan
President
The Chlorine Institute, Inc.
1300 Wilson Boulevard
Arlington, VA 22209
Tel: 703-741-5760
Fax: 703-741-6068
www.chlorineinstitute.org

Competing interests

The author works for a trade association that represents some members of the chlor-alkali industry, the subject of this comment.

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Response to Chlorine Institute's Comments

Renee Dufault (11 February 2009) United Tribes Technical College

RESPONSE TO CHLORINE INSTITUTE’S COMMENTS

We also share the public’s concern about the safety of our food supply. The order of preference for using chlor-alkali chemicals in HFCS manufacturing was provided by the manager of a high fructose corn syrup plant and stated as 1) mercury cell and then 2) membrane grade. The reason given for the preference stated was that mercury cell caustic enhances “product shelf life.”

A literature review of the uptake of mercury by the corn plant indicated that corn has very low levels of mercury even in soils with elevated mercury caused by sludge application (1, 2, 4, 5, 6). After the steeping step in the HFCS manufacturing process, the de-germing process separates the germ from the endosperm (3). The germ is the portion of the corn most likely to contain any mercury and it is removed at that point of the HFCS manufacturing process while the endosperm is used to produce HFCS (3). So to summarize the results of our literature review, corn feedstock is actually a weak vector for carrying mercury into a wet-mill, and the little that may arrive is separated prior to HFCS production (1-3, 7).

The conclusion we made, that mercury-cell caustic soda could be a likely source of mercury in the high fructose corn syrup samples, was substantiated because other obvious sources of mercury contamination were considered less likely. The Chlorine Institute does not provide any evidence that reassures the public that mercury grade caustic soda is safe to use in food manufacturing processes. The amount of mercury that contaminates the mercury-cell chlor-alkali products is variable and depends on quality control and plant operations. These products, which are used world wide in food processing, have not been adequately regulated. The persistence of mercury in HFCS is a cause for concern. Mercury is considered a neurotoxin in any form. It is interesting to note that Sweden recently banned the use of mercury in any form in any product (8). The Swedish Government's decision on a total mercury ban means that alternative, safer techniques will have to be used in dental care, chemical analysis and the chlor-alkali industry (9).

We agree that most of the caustic soda produced in the United States (US) is now produced by chlor-alkali plants that do not use mercury cell technology. It has been reported that only five mercury cell plants are left - Port Edwards is still operating, although it has committed to phasing out mercury cell technology. Although thousands of tons of mercury pollution could be eliminated annually if these five remaining plants in the U.S. switched to cleaner technology, there are still many more mercury cell chlor-alkali plants operating throughout the rest of the world. The US must lead by example and provide leadership in eliminating this outdated chlor-alkali technology worldwide. In 2006, then Senator Barack Obama introduced legislation to phase out all mercury cell use in chlorine plants by 2012. He re-introduced it in 2007. Earlier in 2008, a version of this legislation also was introduced in the House of Representatives. It's time to pass this legislation.

Sincerely,

Dufault et al
References

1. 1999 -- PUBLIC HEALTH STATEMENT MERCURY CAS#: 7439-97-6
http://www.atsdr.cdc.gov/toxprofiles/tp46-c1-b.pdf

2. 2001 -- Distribution of Mercury in Soil and its Concentration in Runoff
from a Biosolids-Amended Agricultural Watershed
http://jeq.scijournals.org/cgi/reprint/30/6/2173.pdf

3. 1974 -- Heavy Metals in Food Products from Corn
http://www.aaccnet.org/cerealchemistry/backissues/1974/Chem51_779.pdf
4. 2007 -- Heavy Metals (Pb, Cd, As, Hg) Contamination of Edible Grains
Grown and Marketed in Nigeria
http://www.scialert.net/pdfs/rjas/2007/192-195.pdf
5. 2007 -- A note on elevated total gaseous mercury concentrations downwind
from an agriculture field during tilling 1: Sci Total Environ. 2007 Dec 15; 388(1-3):379-88. Epub 2007 Aug 20.

6. 2004 -- Heavy metals in soils and crops in Southeast Asia. 1. Peninsular Malaysia Environ Geochem Health. 2004 Dec; 26(4):343-57.

7. 1983 -- Differential Uptake of Mercury Vapor by Gramineous C(3) and
C(4) Plants Plant Physiol. 1983 Aug;72(4):1040-1042.
8. http://ehstoday.com/environment/hazardous-waste/Sweden_bans_mercury_9872/
9. http://www.sweden.gov.se/sb/d/11459/a/118550

Competing interests

None declared

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