Chlordecone
Chlordecone, better known in the United States under the brand name Kepone, is an organochlorine compound and a colourless solid. It is an obsolete insecticide, now prohibited in the Western world, but only after many thousands of tonnes had been produced and used. Chlordecone is a known persistent organic pollutant that was banned globally by the Stockholm Convention on Persistent Organic Pollutants in 2009.
Synthesis
Chlordecone is made by dimerizing hexachlorocyclopentadiene and hydrolyzing to a ketone.It is also the main degradation product of mirex.
History
In the U.S., chlordecone, commercialized under the brand name "Kepone", was produced by Allied Signal Company and LifeSciences Product Company in Hopewell, Virginia. The improper handling and dumping of the substance into the nearby James River in the 1960s and 1970s drew national attention to its toxic effects on humans and wildlife. After two physicians, Dr. Yi-nan Chou and Dr. Robert S. Jackson of the Virginia Health Department, notified the Centers for Disease Control that employees of the company had been found to have toxic chemical poisoning, LifeSciences voluntarily closed its plant on 4 July 1975, and cleanup of the contamination began and a 100-mile section of the James River was closed to fishing while state health officials looked for other persons who might have been injured. At least 29 people in the area were hospitalized as a result of their exposure to Kepone.The product is made in a Diels-Alder reaction shared with pesticides like chlordane and endosulfan. Chlordecone is cited amongst a handful of other noxious substances as the driver for Gerald Ford's approval of the Toxic Substances Control Act in 1976, a United States regulatory bill that was controversial due to the financial burden it put on chemical production companies to get approval for new compounds.
Regulation
In the US, Chlordecone was not federally regulated until after the Hopewell disaster, in which 29 factory workers were hospitalized with various ailments, including neurological.In France it was banned on the mainland only, in 1993.
In 2009, chlordecone was included in the Stockholm Convention on Persistent Organic Pollutants, which bans its production and use worldwide.
On 14 March 2024, the French National Assembly assumed responsibility for the chlordecone contamination affecting populations in Martinique and Guadeloupe.
Toxicology
Chlordecone can accumulate in the liver and the distribution in the human body is regulated by binding of the pollutant or its metabolites to lipoproteins like LDL and HDL. The LC50 is 35 μg/ L for Etroplus maculatus, 22–95 μg/kg for blue gill and trout. Chlordecone bioaccumulates in animals by factors up to a million-fold.Workers with repeated exposure suffer severe convulsions resulting from degradation of the synaptic junctions.
Chronic low level exposure appears to cause prostate cancer in men, and "significant excesses of deaths were observed for stomach cancer in women and pancreatic cancer in women".
Chlordecone has been found to act as an agonist of the GPER, which interacts strongly with the estrogen sex hormone estradiol.
Incidents
The history of chlordecone incidents are reviewed in Who's Poisoning America?: Corporate Polluters and Their Victims in the Chemical Age.James River estuary
In July 1975, Virginia Governor Mills Godwin Jr. shut down the James River to fishing for 100 miles, from Richmond to the Chesapeake Bay. This ban remained in effect for 13 years, until efforts to clean up the river began to show results.Due to the pollution risks, many fishermen, marinas, seafood businesses, and restaurants, along with their employees along the river suffered economic losses. In 1981, a large group of these entities sued Allied Chemical in federal district court, claiming special economic damages from Allied's negligent damage to the fish and wildlife. In a case that sometimes appears in law school courses on Remedies, the court rejected the traditional "economic-loss rule", which requires physical impact causing personal injury or property damage to receive economic damages, and instead allowed a limited group of the plaintiffs—the fishing boat owners, the marinas, and the bait and tackle shops—to recover economic damages from Allied Chemical.