My last posting dealt with zinc, a vital nutrient that can also be toxic. I focus here on manganese, another nutrient that also can also do harm. Inorganic manganese has had longstanding commercial applications, with known hazards for those who work with the metal. Now scientific innovation has managed to produce an entirely new class of manganese-based organic chemicals, signaling a new health threat and a potential environmental disaster.
Such a technological "breakthrough" is akin to what happened when inorganic lead, a poison known since antiquity, was revamped as tetraethyl lead and introduced as a ubiquitous gasoline additive in the 1920s. In fact, the parallels are more than a little scary. A new organic manganese gasoline additive, methylcyclopentadienyl manganese tricarbonyl (MMT), has already been introduced in a number of countries outside the U.S. It is currently under review by the Federal Environmental Protection Agency (EPA). If MMT is ever approved, we can anticipate widespread tail pipe exhaust contamination from manganese. This would be the same story as the environment-wide dispersal of lead from gasoline prior to its ultimate ban in the not too distant past. By the way, the sole manufacturer of MMT is a company named Afton Chemical; it used to be called Ethyl Corporation, which profited for decades from its invention of tetraethyl lead.
The brain is the target of manganese toxicity. It is good for us that biological systems have safety nets: the absorption manganese taken by mouth in the diet is tightly controlled, so that little reaches the brain. This is not the case with inhaled manganese. Almost two hundred years ago, manganese-caused disease was reported among dust-covered workers who processed permanganate used in the early chemical industry. Their odd, debilitating neurological illness had no name at the time - the term Parkinson's disease had yet been coined. Well into the 20th century, manganese continued to cause disease outbreaks. Nor has work-related exposure been eliminated. There continues to be concern over the degree to which the inhalation of manganese-laden fume among welders may lead to Parkinson-like diseases.
If anyone had any remaining questions about the potential of manganese to cause serious disease, these were answered by the victims a new route of poisoning. Injection drug users, primarily in the Baltic countries, started mixing a natural stimulant (extracted from the khat plant) with permanganate to make a more potent drug. Within a few years of starting this practice, such users manifested a severe Parkinson's-like disease typical of manganese poisoning. Even more recently, yet another outbreak has been reported from Turkey, this time from the IV use of an illicit manganese-contaminated "Russian cocktail" of ephedrine tablets, aspirin, and permanganate.
The MMT web page for Afton Chemical (www.aftonchemical.com/Products/mmt) prods us to "imagine the potential." I do. Let us all hope that the EPA is vigilant.
