Mercury in High-Fructose Corn Syrup: What Does It All Mean?
Posted Mar 18 2009 12:00am
By Scott Laster, SafeMinds
Mercury at chlor-alkali manufacturing plants represents one of the main sources of anthropogenic mercury (i.e. mercury contamination originating from human activities). This source of mercury contamination will be gaining more attention in 2009 with the reintroduction of a bill in Congress to stop this unnecessary mercury exposure.
Since the late-1800’s, chlor-alkali plants have used large vats containing several tons of elemental mercury as a catalyst to convert salt water into common chemicals such as caustic soda (sodium hydroxide), potash (potassium hydroxide), chlorine gas, chlorine bleach (sodium hypochlorite), hydrogen gas, and hydrochloric acid. It is well-established in the chemical industry that this process causes some level of mercury contamination in those chemicals. Further, chlor-alkali plants have been the source of extensive mercury contamination via emissions and waste-water effluent, such as the Minimata mercury poisoning incident in Japan. Mercury emissions are measured and accounted for at U.S. chlor-alkali plants. An additional 20 - 100 tons of mercury annually has been unaccounted for (“lost”, but not due to emissions), with some of this mercury contaminating consumer products. Advances in technology have successfully allowed these plants to cost-effectively convert to a mercury-free process. However, as this technology’s use is not federally mandated, there are chlor-alkali plants in the U.S. that continue to use the mercury-based process. Plants using mercury as a catalyst are called “mercury-cell chlor-alkali plants”, and chemicals produced at those plants are known as “mercury-grade” (e.g. “mercury-grade caustic soda”) or alternatively as “rayon-grade”.