Mercury poisoning occurs when a person is exposed to mercury or a compound of mercury, and it can cause severe and even life-threatening illness. The toxicity of mercury means that it affects a broad range of things in the human body, from the mouth, gums and teeth to the central nervous system and internal organs. Heavy exposure to mercury vapour can result in brain damage, leading to death. Mercury is particularly toxic to unborn and young children. Most forms of mercury are known to cause birth defects as well.
Mercury can be taken into the system through ingestion, inhalation or absorption through the skin. The most dangerous form of mercury, in terms of absorption and damage to the human system, is vapor. Liquid mercury (or quicksilver) is not as readily absorbed, and inorganic mercury salt (mercury chloride) doesn’t affect the brain unless the exposure is prolonged or heavy. These forms still damage the internal organs. Mercury compounds tend to be more toxic than elemental mercury to the human system, and organic compounds are more toxic still. Dimethylmercury is the most dangerous compound. It is so toxic that spilling a tiny amount on the skin, or even a latex glove, can be fatal.
Symptoms of mercury poisoning differ slightly depending on whether the exposure is to elemental mercury or mercury compounds. They can include impairment of vision, speech or hearing, and a lack of coordination. Some of the most visible symptoms occur in the skin, such as swelling, pinkness in the cheeks, fingertips and toes, and dead skin peeling off in layers. A victim of mercury poisoning may also feel itching, burning or numbness in the skin, experience memory gaps and mood swings, sweat more than normal, have muscle weakness, a consistently faster-than-normal heartbeat, hypersalivation and high blood pressure. Children may have red cheeks, nose and lips, develop a rash or photophobia and lose hair, teeth and nails.
Most of the symptoms of mercury poisoning disappear after treatment. Damage caused by prolonged exposure can be permanent, particularly in children, unborn babies and infants. Young’s syndrome, which affects fertility and the sinuses, is thought to be caused by childhood exposure to mercury.
Mercury poisoning can occur through eating fish with a high mercury level. The dangers posed by high-mercury fish prompted the Sea Turtle Restoration Project to create the ‘Got Mercury?’ campaign to increase public awareness of the dangers of fish. Mercury can also be consumed via vegetables that have been exposed to mercury vapor or foods which contain mercury residue from processing.
Other exposure to mercury can be caused by cosmetics, batteries and fluorescent lightbulbs. Although the US has banned the use of mercury in cosmetics, some imported products contain mercury chloride. This can be readily absorbed through the skin. Fluorescent lightbulbs contain elemental mercury as a liquid or vapor and present a risk to all if broken indoors.
As mercury exists in the system naturally, diagnosis of mercury poisoning can be tricky. Organic mercury poisoning can be detected in a blood or hair analysis, but inorganic mercury requires a broad analysis of the symptoms and the victim’s situation. Treatment for mercury poisoning differs depending on the type of exposure – topic exposure might require a scrub-down, washing of clothes and rinsing out of the eyes, whereas ingestion is treated like any other caustic substance ingestion. All forms might require chelation therapy. This introduces a chemical agent into the body to absorb the toxic content and remove it from the body. Chelation therapy is also used as a diagnostic tool, flushing through the system to test whether there is a toxic level of mercury in the body.