Heavy Metal Poisoning Health Article

Definition

Heavy metal poisoning is the toxic accumulation of heavy metals in the soft tissues of the body.

Description

Heavy metals are chemical elements that have a specific gravity (a measure of density) at least five times that of water. The heavy metals most often implicated in human poisoning are lead, mercury, arsenic, and cadmium. Some heavy metals, such as zinc, copper, chromium, iron, and manganese, are required by the body in small amounts, but can be toxic in larger quantities. Heavy metals may enter the body through food, water, or air, or by absorption through the skin. Once in the body, they compete with and displace essential minerals such as zinc, copper, magnesium, and calcium, and interfere with organ system function. People may come in contact with heavy metals in industrial work, pharmaceutical manufacturing, and agriculture. Children may be poisoned as a result of playing in contaminated soil.

Sources of exposure for some heavy metals

• lead: old paint, leaded gasoline, old pipes
• mercury: contaminated fish, industrial and agricultural wastes
• cadmium: industrial waste, insecticides, old galvanized pipes
• arsenic: insecticides and industrial processes, some drinking water

Causes & symptoms

Symptoms will vary, depending on the nature and quantity of the heavy metal, and whether it was ingested or inhaled. Patients who ingest a heavy metal may complain of cramps, nausea, vomiting, diarrhea, stomach pain, headache, sweating, and a metallic taste in the mouth. Mercury can cause skin burns if it has touched the skin, and inhaled mercury vapor can cause severe inflammation of the lungs. If lead is inhaled in the form of lead dust, insomnia, headache, mania, and convulsions may occur. In severe cases of heavy metal poisoning, patients exhibit obvious impairment of cognitive, motor, and language skills. The expression "mad as a hatter" comes from the mercury poisoning prevalent in seventeenth-century France among hatmakers who soaked animal hides in a solution of mercuric nitrate to soften the hair.