Mercury, despite its natural presence and historical use as medicine, is a toxic metal. It exists in small amounts in certain animals and plants, and some businesses use mercury in their products. Typically, these small doses do not pose much risk. However, exposure to high amounts of mercury can result in mercury poisoning, which can be dangerous and difficult to cure. Poisoning is usually the result of long-term exposure to mercury, but some cases may develop quickly from a singular incident.

Early Symptoms

Mercury poisoning has several stages of symptoms that occur in correlation with the length of exposure and the severity of the poisoning. Early symptoms are mostly neurological issues. Feelings of anxiety or nervousness are common, and mood changes and irritability may follow. Some individuals experience depressive symptoms. The worst of the early symptoms are feelings of numbness throughout the body and physical tremors. As mercury builds up in the system, the poisoning worsens and more advanced symptoms develop.

Advanced Symptoms

More harmful symptoms appear differently in adults and children. Adults may experience a distinct metallic taste accompanied by nausea and vomiting. They may also experience difficulty with breathing, speaking, walking, and standing. Muscle weakness and a general lack of coordination are also typical. Children exhibit similar symptoms, but may also experience developmental issues. Mercury poisoning can delay the development of spatial awareness and cognitive abilities. Many children develop difficulties understanding language and may have trouble speaking.

Long-term Damage

Mercury poisoning primarily causes neurological issues. A study in the Journal of Preventive Medicine and Public Health reflects this, listing many issues resulting from nerve damage. Some adults had signs of intelligence disorders and low IQ, while others had slow reflexes and poor motor skills. Symptoms similar to ADHD also appeared. The study showed many people experienced paralysis and numbness as well. Long-term mercury poisoning also affects the reproductive system. Male subjects possessed lower sperm counts and both sexes had decreased fertility.

Common Exposure Methods

The vast majority of people develop mercury poisoning from consuming seafood. Methylmercury is one of the most toxic forms. Sea creatures such as shrimp ingest this metal from the ocean. The methylmercury then travels along the food chain. Because larger creatures consume more food, the methylmercury accumulates in their bodies in higher quantities. Fish and sea creatures that are higher on the food chain are more likely to have large amounts of mercury. The fish people most commonly consume that contain methylmercury are white tuna, albacore tuna, bigeye tuna, shark, swordfish, mackerel, salmon, and catfish.

Other Causes

While most people accumulate mercury from seafood, mercury exists throughout the world in many forms. Certain amalgam dental fillings may be upwards of 50 percent mercury, and though most dentists opt to use contemporary materials instead, some still use the traditional type. Some brands of cosmetics and skin care products use small amounts of mercury as a preservative. Additionally, older products such as paints, jewelry, and thermometers may contain mercury. Some businesses, such as coal plants, create mercury emissions that can poison employees and individuals living near the factories.

Soluble Mercury

Some of mercury’s more dangerous forms are water soluble. Methylmercury is one such form, though inorganic mercury compounds pose similar risks. Methylmercury is released into the environment when volcanoes, forest fires, or weathering create inorganic mercury. Microbes in aquatic systems act on the mercury and transform it into methylmercury. Inorganic mercury compounds are typically salts, such as mercuric chloride and mercurous chloride. These compounds and methylmercury have such high solubility that the digestive system easily absorbs them. The salts are more likely to cause stomach and liver damage, while methylmercury can damage the brain.

Elemental Mercury

The liquid metallic form of mercury, quicksilver, is not nearly as soluble as methylmercury or inorganic mercury compounds. This means skin contact and digestion are not sufficient means to absorb it. Instead, the danger of elemental mercury lies in its vapor. The skin can absorb the vapor, but the respiratory tract is responsible for 80 percent of inhaled mercury. Even low concentrations of mercury vapor can result in mercury poisoning because the vapor more easily enters the circulatory system, which distributes it throughout the rest of the body.

Diagnosis

In most cases, diagnosing mercury poisoning is difficult. Usually, a physician must understand the history of exposure or find traces of mercury in the body. For inorganic and elemental mercury, doctors may ask questions concerning work and diet history to discover possible sources. Doctors can discover long-term mercury exposure through urine tests. Organic mercury, such as methylmercury, may require a hair or blood analysis. Some treatments for mercury and other metal poisonings may prevent the use of these tests.

Basic Treatments

For less severe instances of mercury poisoning, physicians will generally recommend preventing all further exposure to mercury. This may include eliminating seafood from the diet and leaving a workplace that contains mercury. If the mercury poisoning results in a long-term issue, doctors will usually treat and manage that issue separately from the poisoning. Individuals who experience severe mercury poisoning may require a more extensive treatment plan which may include chelation therapy.

Chelation Therapy

The word chelation refers to the bonding of ions and molecules to metal ions. Essentially, chelating agents bond to the heavy metals poisoning the body. Doctors then remove the agents, along with the poisonous metals. This treatment can be dangerous and requires direct and careful medical supervision. Side effects usually include dehydration and kidney damage. Chelation therapy has recently become an alternative option for other health issues, but health organizations around the world warn against using it for anything other than heavy metal poisoning.