Dimethylmercury
Dimethylmercury is an extremely toxic organomercury compound with the formula (CH3)2Hg[5]. It is a volatile, flammable, dense, and colorless liquid that is one of the strongest known neurotoxins[5]. The compound was first prepared by George Buckton in 1857 and has been studied for its reactivity and physical properties[5].
Toxicity and Safety Concerns
Dimethylmercury is highly toxic and dangerous to handle. Absorption of doses as low as 0.1 mL can result in severe mercury poisoning[5]. The risks are enhanced because of the compound's high vapor pressure, making it easy to inhale, and its high lipophilicity, which allows it to absorb through the skin and into body fat very easily[5]. It can permeate many materials, including many plastics and rubber compounds, making it difficult to handle safely[5].
The American Occupational Safety and Health Administration advises handling dimethylmercury with highly resistant laminated gloves, an additional pair of abrasion-resistant gloves worn over the laminate pair, and also recommends using a face shield and working in a fume hood[3]. The compound is metabolized after several days to methylmercury, which crosses the blood–brain barrier easily and has a tendency to bioaccumulate[5]. The symptoms of poisoning may be delayed by months, resulting in cases in which a diagnosis is ultimately discovered, but only at a point in which it is too late or almost too late for an effective treatment regimen to be successful[5].
Incidents and Fatalities
One notable incident involving dimethylmercury poisoning occurred in 1997, when a chemistry professor, Karen Wetterhahn, died after accidentally spilling a few drops of the substance on her gloved hand[1]. The spill occurred while she was working under a fume hood and wearing latex gloves, which did not provide sufficient protection against the highly toxic compound[1][3]. Wetterhahn developed symptoms five months after the incident, including numbness and tingling in her lower extremities, difficulty with vision, walking, speaking, and hearing, and eventually fell into a coma and died[1][3].
Precautions and Guidelines
Due to the extreme toxicity of dimethylmercury, it is essential to take strict precautions when handling the substance. This includes wearing appropriate personal protective equipment, such as highly-resistant laminate gloves and a face shield, and working in a certified chemical fume hood[4]. It is also crucial to dispose of waste dimethylmercury following hazardous waste procedures and to wash hands and forearms thoroughly with soap and water after handling the substance[4].
Conclusion
Dimethylmercury is an extremely toxic substance that requires utmost care and caution when handling. Its high volatility, flammability, and ability to permeate many materials make it a significant hazard in laboratory settings. The incident involving Karen Wetterhahn serves as a stark reminder of the dangers of working with highly toxic substances and the importance of adhering to strict safety protocols to minimize the risk of exposure and poisoning.
Citations:
[1] https://cen.acs.org/safety/lab-safety/25-years-Karen-Wetterhahn-died-dimethylmercury-poisoning/100/i21
[2] https://www.nejm.org/doi/full/10.1056/NEJM199806043382305
[3] https://www.osha.gov/publications/hib19980309
[4] https://www.ehs.harvard.edu/sites/default/files/lab_safety_guideline_dimethylmercury.pdf
[5] https://en.wikipedia.org/wiki/Dimethylmercury