Lead poisoning is a medical condition caused by increased blood lead levels. Lead may cause irreversible neurological damage as well as renal disease, cardiovascular effects, and reproductive toxicity.
Lead can also be found in drinking water. It can come from plumbing and fixtures that are either made of lead or have trace amounts of lead in them. Exposure to metallic lead such as small lead objects, can rarely lead to an increase in blood lead levels if the lead is retained in the gastrointestinal tract or appendix. Lead may be contracted through the mucous membranes through direct contact to mouth, nose, eyes, and breaks in the skin.
The symptoms of chronic lead poisoning include neurological problems, such as reduced cognitive abilities, or nausea, abdominal pain, irritability, insomnia, metal taste in oral cavity, excess lethargy or hyperactivity, headache and, in extreme cases, seizure and coma. Lead poisoning is also associated with gastrointestinal problems, such as constipation, diarrhea, vomiting, poor appetite, weight loss, all of which are common in acute poisoning. Other associated effects are anemia, kidney problems, and reproductive problems.
In humans, lead toxicity sometimes causes the formation of a bluish line along the gums, which is known as the "Burton's line", although this is very uncommon in young children. Blood film examination may reveal "basophilic stippling" of red blood cells, as well as the changes normally associated with iron deficiency anemia (microcytosis and hypochromia).
A direct link between early lead exposure and extreme learning disability has been confirmed by multiple researchers and child advocacy groups.
Outside of occupational hazards, the majority of lead poisoning occurs in children under age twelve. The main sources of poisoning are from ingestion of lead contaminated soil and from ingestion of lead dust or chips from deteriorating lead-based paints. This is particularly a problem in older houses where the sweet-tasting lead paint is likely to chip, but deteriorating lead-based paint can also powder and be inhaled. Small children also tend to teethe and suck on painted windowsills as they look outside. In most American states, landlords and those selling such houses are required to inform the potential residents of the danger.
Although children are at a greater risk from lead exposure, adult exposures can also result in harmful health effects. Most adult exposures are occupational and occur in lead-related industries such as lead smelting, refining, and manufacturing industries. One frequent source of lead exposure to adults is home renovation that involves scraping, remodeling, or otherwise disturbing lead-based paint. Adults can also be exposed during certain hobbies and activities where lead is used. Workers may inhale lead dust and lead oxide fumes, as well as eat, drink, and smoke in or near contaminated areas, which increases their probability of lead ingestion.