When most people hear the word mercury, they think of old thermometers or science-class experiments. But mercury isn’t just a relic of the past—it’s a real, ongoing environmental and public-health concern. From large ocean fish to certain industrial processes, mercury continues to make its way into our ecosystems and, ultimately, into our bodies.
In this post, we’ll break down what mercury poisoning is, how it happens, what symptoms to watch for, and—most importantly—how to reduce your exposure without turning everyday life into a stress test.
What Is Mercury, Exactly?
Mercury is a naturally occurring heavy metal. It exists in a few different forms:
- Elemental mercury – the shiny liquid metal you might picture from thermometers. It generally deposits in eyes causes mercuria lentis on exposure.
- Inorganic mercury compounds – often used in some industrial processes.
- Organic mercury compounds like methylmercury – the kind that accumulates in fish and poses the most concern for human exposure.
Methylmercury is the real troublemaker. It builds up through the food chain, becoming more concentrated in large predatory fish like tuna, swordfish, and king mackerel.
Toxic compounds of mercury are: Inorganic salts such as mercuric chloride (most toxic), mercuric sulphide (red crystalline non-poisonous powder). Organic salts includes methyl mercury, ethyl mercury, diethyl mercury, phenyl mercury etc.
How Does Mercury Poisoning Happen?
Most people are exposed through eating contaminated seafood. Others might encounter mercury through:
- Occupational exposure (certain manufacturing or mining sectors)
- Broken items containing elemental mercury
- Contaminated soil or water in some regions
Mercury doesn’t leave the body quickly, so repeated exposure—especially through diet—can lead to a gradual build-up.
Elemental mercury exposed as a vapour, so symptoms develop as headache, nausea, cough, chest pain, pulmonary oedema and many CNS symptoms.
Inorganic mercuric salts exposed through gastric ingestion and symptoms seen as gastroenteritis, mouth and throat becomes corroded, greyish white blood tinged vomitus and renal failure.
Organic salts more likely develops symptoms of CNS like ataxia, paraesthesia, hearing loss, dysarthria, tremors, paralysis etc.
Common Symptoms of Mercury Poisoning
Symptoms depend on the type and amount of mercury involved, but may include:
Neurological symptoms
- Tingling or numbness in hands, feet, or around the mouth
- Tremors
- Difficulty with coordination
- Memory problems or cognitive changes
Physical symptoms
- Weakness or fatigue
- Vision or hearing changes
- Headaches
- Speech difficulties
In severe cases
Mercury poisoning can affect the lungs, kidneys, and immune system. Pregnant individuals need to be especially cautious because mercury can affect fetal brain development.
(Important note: These symptoms are not specific only to mercury poisoning. Anyone who suspects exposure should consult a medical professional for proper testing and evaluation.)
In chronic cases
Long term exposure mercury named differently such as pink disease (acrodynia) idiosyncratic hypersensitivity reactions due to repeated exposure, minamata disease caused by eating contaminated fishes, mercuria lentis, hatter’s shake or Danbury tremors seen in workers of glass blowing factories and mercurial erethism.
Mercurial erethism seen in chronic inorganic mercuric toxicity first described by kussmaul in persons of mirror manufacturing firms. Symptoms were insomnia, depression, feeling of embarrassment, timidity, delusions, hallucinations and suicidal melancholia.
Who Is Most at Risk?
- Pregnant or breastfeeding individuals
- Children, whose developing nervous systems are especially sensitive
- People who eat large amounts of high-mercury fish
- Workers in industries where mercury exposure is possible
How to Reduce Your Risk
You don’t have to ditch seafood altogether. Many fish are low in mercury and rich in omega-3s.
Choose lower-mercury options, such as:
- Salmon
- Sardines
- Shrimp
- Pollock
- Tilapia
Limit high-mercury fish, including:
- Swordfish
- King mackerel
- Shark
- Bigeye tuna
Other practical tips:
- Be cautious with antique items or old thermometers containing mercury.
- Follow safety guidelines if working in environments where mercury exposure is possible.
- Pay attention to local fish advisories if you catch your own seafood.
- DMSA or succimer (10 mg/kg orally every 8h for 5 days and then 12 hr for 2 weeks oral) is chelating agent used as antidote in hospital settings.
Why Mercury Still Matters Today
Even though many mercury-containing products and processes have been phased out, environmental mercury pollution is still a global issue. Industrial emissions can travel long distances, making it a shared responsibility. Awareness is the first step toward reducing exposure—both personally and collectively.
