All That Shines Is Not Gold, Sometimes It Poisons You
When I was a child having a fever was common occurrence. Therefore, I was used to get my temperature checked and the thermometer always caught my attention. The thermometer we used to have was a mercury one. That shiny liquid metal always fascinated me so much that I could stare at it for hours, even though I could not understand how it worked despite many explanations from my parents.
Then one day the glass of the thermometer slightly cracked, and that shiny liquid metal got out. The first instinct was to go touch it. Fortunately, my parents stopped me before I could even try and gave me a very long on the dangers of mercury. Moral of the story: don’t touch it if you don’t want to get mercury poisoning.
The number 80
To understand what mercury poisoning is, the first step is to look at the element itself. Mercury is the 80th element of the periodic table that appears like a mirror-like dense liquid. It is used in numerous products from batteries, thermometers, cosmetics, switches, dental fillings and so on thanks to its chemical and physical characteristics. Such features include being the only liquid metal at room temperature, being a good electricity conductor, having high density and expanding when heated. It is found in three states: elemental (metallic), inorganic and as methylmercury.
In spite of its chemical characteristics and vast uses mercury is an incredibly toxic element that causes health issues when inhaled, ingested, absorbed by skin or injected due to its multiple forms. All living things contain mercury in small percentages, generally in the form of organic methylmercury, but fish are generally the ones having the most.
How does mercury poisoning affect you?
The effects that mercury has on our bodies vary between the elements’ forms, the dosage, the method of exposure with methylmercury being the most dangerous one. Methylmercury and elemental mercury affect both the central and peripheral nervous systems, thus acting as neurotoxins. The former shows symptoms such impaired vision, walking, speech, uncoordinated movements and muscle weakness and a very specific feeling of having “pins and needles” in your extremities and around the mouth. The latter manifests with headaches, mood swings, memory issues, insomnia and usually tremors.
This is what makes mercury poisoning so incredibly scary in my opinion: the fact that its symptomatology is so vague that it can be hard to pinpoint the cause if we are unaware that we were exposed.
A harrowing history
Throughout history there have been many stories of mercury poisoning that show that one poisoning is not like the other.
I want to focus on Minamata Disaster and the case of Karen Wetterhahn to illustrate the dangers of mercury poisoning especially when methylmercury is involved.
During the 1950s wastewater from a chemical plant containing methylmercury was discharged in the waters of Minamata, a Japanese city in the Kumamoto Prefecture, contaminating the fish and shellfish of the bay. Ingesting the fish meant ingesting considerable amounts of mercury and for years the local population suffered the poisoning symptoms without knowing what was affecting them. This was until 1956 when finally the cause was determined to be mercury poisoning, but at that point was too late: in 36 years following the ecological disaster 1043 people would die out of 2252 diagnosed with Minamata disease.
Another famous yet tragic case was that of scientist Karen Wetterhahn in 1996. In August of that same year she was working in her lab at Dartmouth College when she spilled a single drop of dimethylmercury on her gloved hand. She followed all the precautions during her experiment so after her work she went home without realising what had just happened.
For five months she suffered from loss of balance and impaired speech until she was finally diagnosed with mercury poisoning. Unfortunately, at the time it was not known that dimethylmercury could permeate latex gloves so no therapy was able to save Wetterhahn from the debilitating neurological disease that followed. She passed away 10 months after that mercury spill. Her case became famous for its tragic nature as well from what was learned from it on the dangers of dimethylmercury.
As we learn more and more on mercury and its toxic effects, the scientific community is working on reducing our reliance on it with the 2013 Minamata Convention being a step in the right way.
Perhaps at the time, when I saw that mercury spilling out of the thermometer, I did not understand well what was going on. However, I know now that all that shines is not gold and that sometimes it can poison you.
References and further reading:
- Mercury and health: https://www.who.int/news-room/fact-sheets/detail/mercury-and-health
- Mercury exposure and poisoning: https://www.betterhealth.vic.gov.au/health/healthyliving/mercury-exposure-and-poisoning
- Mercury thermometers: https://www.epa.gov/mercury/mercury-thermometers
- Mercury Toxicity: https://emedicine.medscape.com/article/1175560-overview
- The Minamata Disaster and the Disease That Followed: https://www.verywellhealth.com/minamata-disease-2860856
- Health Effects of Exposures to Mercury: https://www.epa.gov/mercury/health-effects-exposures-mercury
- Minamata disease: methylmercury poisoning in Japan caused by environmental pollution: https://pubmed.ncbi.nlm.nih.gov/7734058/
- Scientist’s Death Helped Increase Knowledge of Mercury Poisoning: https://www.latimes.com/archives/la-xpm-1997-sep-14-mn-32049-story.html