Is Parkinson’s disease, ‘world’s fastest growing brain disease,’ mostly preventable? Study offers clues

[Farooqji]

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[SilentEchoes]

Trichloroethylene was discovered by Emil Fischer in 1864 by reduction of hexachloroethane with hydrogen. Commercial production began in Germany, in 1920 and in the US in 1925.

TCE is used primarily to make refrigerants and other hydrofluorocarbons and as a degreasing solvent for metal equipment. TCE is also used in some household products, such as cleaning wipes, aerosol cleaning products, tool cleaners, paint removers, spray adhesives, and carpet cleaners and spot removers. Commercial dry cleaners also use trichloroethylene as a spot remover.

TCE may be found in the air, water, and soil at places where it is produced or used. It breaks down slowly and remains in the environment for a long time. It readily passes through soil and can accumulate in groundwater. Because this chemical was used extensively by the US military to degrease equipment, contaminated soil and groundwater can be found near many current and former military bases.

Prolonged or repeated exposure of trichloroethylene causes kidney cancer. Some evidence suggests that it may be associated with an increased risks of non-Hodgkin lymphoma and, possibly, liver cancer and prostate cancer. EPA has classified it as a known carcinogen. It's linked to neurological toxicity, immunotoxicity, developmental toxicity and birth defects.

Historically, TCE was used as a volatile surgical anesthetic and as an inhaled obstetrical analgesic in millions of patients. Pioneered by Imperial Chemical Industries in Britain, its development was hailed as an anesthetic revolution. Originally thought to possess less hepatotoxicity than chloroform, and without the unpleasant pungency and flammability of ether, TCE use was nonetheless soon found to have several pitfalls. These included promotion of cardiac arrhythmias, low volatility and high solubility preventing quick anesthetic induction, reactions with soda lime used in carbon dioxide absorbing systems, prolonged neurologic dysfunction when used with soda lime, and evidence of hepatotoxicity as had been found with chloroform. The Food and Drug Administration banned such use in the United States in 1977. [Anesthesia is toxic and contributes to brain damage.]

The chemical compound trichloroethylene (TCE) is a halocarbon with the formula C2HCl3, commonly used as an industrial solvent. It is a clear, colourless non-flammable liquid with a chloroform-like sweet smell. Despite its widespread use as a metal degreaser, trichloroethylene itself is unstable in the presence of metal over prolonged exposure. Definitive documentation of 1,4-dioxane as a stabilizing agent for TCE is scant due to the lack of specificity in early patent literature describing TCE formulations. Other chemical stabilizers include ketones such as methyl ethyl ketone.

When inhaled, trichloroethylene produces central nervous system depression resulting in general anesthesia. These effects may be mediated by trichloroethylene acting as a positive allosteric modulator of inhibitory GABA and glycine receptors. Higher concentrations result in tachypnea. Many types of cardiac arrhythmias can occur and are exacerbated by epinephrine (adrenaline). It was noted in the 1940s that TCE reacted with carbon dioxide (CO2) absorbing systems (soda lime) to produce dichloroacetylene and phosgene. [wouldn't TCE also react to CO2 in the human body to produce phosgene a chemical warfare gas? en.wikipedia.org/wiki/Phosgene]

This is alarming, small amounts of phosgene occur from the breakdown of organochlorine compounds, such as chloroform. Isn't this the origin of toxicity when metabolized in the body? Historically used in military settings, phosgene today is a chemical intermediate in dye production, pesticides, livestock feed chemicals, pharmaceuticals, and organic intermediates. I feel like there's a chemical slight of hand going on here with TCE. It will be banned as a solvent and live on as an intermediate in other hazardous chemicals. That's how the EPA works.

SE