What is "lead poisoning"

n. 1 A chronic intoxication produced by the absorption of lead into the body, characterized by severe colicky pains, a dark line along the gums, and local muscular paralysis. 2 (context slang English) Being shot by a firearm.

n. toxic condition produced by the absorption of excessive lead into the system [syn: plumbism, saturnism]

Lead poisoning is a type of metal poisoning caused by increased levels of the heavy metal lead in the body. Like most toxic heavy metals, lead interferes with a variety of body processes and is toxic to many organs and tissues, including the heart, bones, intestines, kidneys, and reproductive and nervous systems. The brain is the organ most sensitive to lead exposure. Lead interferes with the development of the nervous system and is therefore particularly toxic to children, causing potentially permanent learning and behavior disorders including violence. Symptoms include abdominal pain, confusion, headache, anemia, irritability, and in severe cases seizures, coma, and death.

Routes of exposure to lead include contaminated air, water, soil, food, and consumer products. Occupational exposure is a common cause of lead poisoning in adults. According to estimates made by the National Institute of Occupational Safety and Health (NIOSH), more than 3 million workers in the United States are potentially exposed to lead in the workplace. One of the largest threats to children is lead paint that exists in many homes, especially older ones; thus children in older housing with chipping paint or lead dust from moveable window frames with lead paint are at greater risk. Prevention of lead exposure can range from individual efforts (e.g., removing lead-containing items such as piping or blinds from the home) to nationwide policies (e.g., laws that ban lead in products, reduce allowable levels in water or soil, or provide for cleanup and mitigation of contaminated soil, etc.)

Elevated lead in the body can be detected by the presence of changes in blood cells visible with a microscope and dense lines in the bones of children seen on X-ray, but the main tool for diagnosis is measurement of the blood lead level. When blood lead levels are recorded, the results indicate how much lead is circulating within the blood stream, not the amount stored in the body. There are two units for reporting blood lead level, either micrograms per deciliter (µg/dl), or micrograms per 100 grams (µg/100 g) of whole blood, which are numerically equivalent. The Centers for Disease Control (US) has set the standard elevated blood lead level for adults to be 10 µg/dl of the whole blood. For children the number is set much lower at 5 µg/dl of blood as of 2012 down from a previous 10 µg/dl. Children are especially prone to the health effects of lead. As a result, blood lead levels must be set lower and closely monitored if contamination is possible. The major treatments are removal of the source of lead and chelation therapy (administration of agents that bind lead so it can be excreted).

Humans have been mining and using this heavy metal for thousands of years, poisoning themselves in the process. Although lead poisoning is one of the oldest known work and environmental hazards, the modern understanding of the small amount of lead necessary to cause harm did not come about until the latter half of the 20th century. No safe threshold for lead exposure has been discovered—that is, there is no known sufficiently small amount of lead that will not cause harm to the body.