Investigating the Neurophysiological and Neurobehavioral Effects of Tetrachloroethylene (PCE) exposure in organisms
By. Nabin Won
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“Science…is the torch which illuminates the world.” These words, echoed by the well-known chemist and microbiologist Louis Pasteur, emphasizes the significance of evolution of science and its pivotal role in today’s society. While the development of science and technology has facilitated humanity’s understanding of the world and improved one’s quality of life, it has also brought upon countless environmental threats and hazards. Among the most threatening are the toxins and chemicals present in one’s immediate environment that individuals are often unaware of, resulting in potential long-term health consequences and hazards. Such dangers can be seen in Tetrachlorethylene – also known as Perchloroethylene (PCE) – that is widely utilized in water repellents, dry cleaning, paint removers, solvents for chemical extractions, etc. The most significant yet understudied field is its effect on the central nervous system (CNS), given that the majority of the studies conducted in the past are primarily focused on its effect on the liver and kidney. Therefore, in an attempt to raise further awareness of these invisible toxins in our everyday environments, this article will explore the neurobehavioral and neurophysiological effects of Tetrachlorethylene on organisms.
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Tetrachloroethylene, although not widely known amongst the general public, is the most prevalent chemical in degreasers, dry cleaning agents, paint removers, and solvents for chemical extraction due to its durability and ability to adhere to plastics, metal, rubber, leather, etc. In addition to its use in these components, PCE is among the most ubiquitous chlorinated compounds found in groundwater contamination, (Burmaster 1982) a process triggered when PCE leached from the vinyl lining of water distribution pipes. (Webler and Brown 1993). The chemical is also released into the atmosphere from dry-cleaned or consumer products, and “is able to transport long distances as it breaks down slowly in the air.” (ATSDR). Consequently, there are countless dangers and risks for accidental or even unknown exposure to the substance through the inhalation of vapor or through the consumption of polluted drinking water, thus increasing the concern for the health effects associated with the exposure.
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Although the biological plausibility for the neurotoxic effects associated with Tetrachloroethylene is not yet explicitly researched and lacks the sufficient evidence to derive conclusions, it is highly likely that exposure to PCE may result in the loss of Myelin – a fatty substance that surrounds the axons of the neurons, serving as an electrical conductor to transmit electrical impulses quickly and efficiently along the nerve cells. If myelin is damaged, the nerves lose their capability to conduct electrical impulses normally, which may lead to the death of underlying nerve fibers; this could physically weaken one’s muscles, damage coordination, and result in paralysis. In fact, when Tetrachloroethylene was tested on Myelin in the dorsal hippocampus of a developing rat, a significant decrease in myelinated fibers could be found in the stratum lacunosum-moleculare, an area comprised of dendritic profiles of neurons that receive input from the entorhinal cortex. (L G Isaacson 1989). In addition to the loss of myelin, previous studies also show that PCE may induce apoptotic neurodegeneration, which refers to the death of nerve cells through the interference of the NMDA and GABA receptor systems. (J W Olney, 2000).
Numerous neurobehavioral effects of Tetrachloroethylene have been studied, one of which portrays a strong association between exposure and the use of illicit drugs. In fact, highly exposed individuals experienced a 30-40% increase in risk of using major illicit drugs, including crack/cocaine, psychedelics/hallucinogens, club/designer drugs, and heroin, along with a 30-60% increase in the risk of certain smoking and drinking behaviors among highly exposed subjects(Aschengrau 2016). Short-term effects of exposure to Tetrachloroethylene can also be observed in past studies, effects that include mood changes, slight ataxia, faintness, and dizziness in low concentrations. (Carpenter 1937). All of these studies portray the detrimental effects of Tetrachloroethylene in one’s brain and the neurobehavioral consequences that it induces.
While further research is needed to fully understand the neurological effects of PERC, existing studies suggest that exposure to the chemical may have detrimental effects on the human brain, leading to numerous neurobehavioral disorders. This article highlights the importance of understanding the toxicity of the chemical and its potential neurological risks and highlights the increased risk of exposure to the chemical due to its widespread presence in the environment. Continuous endeavors to raise awareness in the danger of everyday chemicals should be continued, along with greater efforts to further research its hazards in the forthcoming years.
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Citations
https://www.tandfonline.com/doi/abs/10.1080/00139157.1982.9932469
https://www.atsdr.cdc.gov/sites/toxzine/tetrachloroethylene_toxzine.html
https://www.consumernotice.org/environmental/trichloroethylene/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2432054/
https://pubmed.ncbi.nlm.nih.gov/2743138/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1637813/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4916338/
https://stacks.cdc.gov/view/cdc/6294
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