Xylenes

  • Source
    • Xylenes are a naturally occuring aromatic hydrocarbon that is used in a wide variety of industries that range from rubber manufacturing to medical laboratory uses. It is a colorless, flammable liquid with a sweet odor and can exist in one of three isomers of a benzene ring with a methyl group (1).
    • Chemical structures of the xylene isomers | Download Scientific Diagram Figure 1: Isomers of xylenes. Source: https://www.researchgate.net/figure/Chemical-structures-of-the-xylene-isomers_fig2_281971885
  • Biotransformation
    • Xylene is most likely to enter the body when it is inhaled and is absorbed through the lungs- the amount of xylene retained ranges from 50-75% of the amount that is inhaled (1). According to the Centers for Disease Control (CDC), xylene is transformed in the liver into a more water soluble compound and is rapidly eliminated in urine within 18 hours after exposure.
    • The respiratory system – EFMURGIFigure 2: The respiratory system is effected by xylenes. Source: https://efmurgi.wordpress.com/2019/09/25/the-respiratory-system/
  • Carcinogenicity
    • According to the New Jersey Department of Health, xylenes are on the right to know hazardous substances list, but they are not classified as a carcinogen (2).
  • Mechanism of Action (if known)
    • Xylene disturbs the action of proteins essential to normal neuronal function either by disruption of the lipid environment in which the membrane proteins function or by direct interaction with the proteins in the membranes. It has been suggested that a metabolic intermediate like methyl benzaldehyde could be responsible for the toxicity of xylene, and oxidation of xylene to these intermediates by microsomal enzyme systems may occur in the brain (3).
  • Target organ(s)
    • According to the CDC, all three xylene isomers have similar effects on health and target the eyes, respiratory system, gastrointestinal tract, liver, and kidneys (4).
  • Signs and symptoms of toxicity
    • Irritation of the skin, eyes, nose, and throat
    • Difficulty breathing
    • Confusion
    • Headaches and dizziness
    • Routes of xylene liberate to the environment and its toxic effects on... | Download Scientific DiagramFigure 3: Signs and symptoms of xylene toxicity. Source: https://www.researchgate.net/figure/Routes-of-xylene-liberate-to-the-environment-and-its-toxic-effects-on-human-health-from_fig2_284438081
  • Genetic susceptibility or heritable traits
    • While xylene is a teratogen and may harm a developing fetus, damage depends on exposure and is not heritable.
  • Historical or unique exposures
    • Xylene was discovered by Michael Mojzesz Szware, a physical chemist, in 1947 at the University of Manchester in England while investigating a class of aliphatic carbon-hydrogen bonds where carbon is directly attached to the benzene ring, then was synthesyzed in 1951 at UCLA by Dr. Donald Cram (5).
    •  PictureFigure 4: Image of Michael Mojzesz Szware. Source: https://audreycryanp-xylene.weebly.com/
  • Treatments
    • Skin exposure
      • Wash the area with water for at least 15 minutes
      • Treat with ointment
    • Gastrointestinal
      • Do not induce vomiting
      • Give milk or water to drink as long as the individual does not indicate difficulty swallowing
      • Gastric lavage done by a medical professional only
    • Respiratory
      • Provide breathings upport if necessary
  • Biomarkers
    • The commonly used urinary biomarkers for the aromatic solvents toluene (T), ethylbenzene (E), and m-xylene (X) are o-cresol, mandelic acid, and m-methylhippuric acid (6).
  • Sources
    • 1. https://www.atsdr.cdc.gov/toxprofiles/tp71-c1.pdf
    • 2. https://nj.gov/health/eoh/rtkweb/documents/fs/2014.pdf
    • 3.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2996004/
    • 4. https://www.cdc.gov/niosh/npg/npgd0668.html
    • 5. https://audreycryanp-xylene.weebly.com/
    • 6. https://academic.oup.com/toxsci/article/144/2/414/1717693