Lead and lead compounds can be highly toxic when eaten or inhaled. Although lead is absorbed very slowly into the body, its rate of excretion is even slower. Thus, with constant exposure, lead accumulates gradually in the body. It is absorbed by the red blood cells and circulated through the body where it becomes concentrated in soft tissues, especially the liver and kidneys. Lead can cause lesions in the central nervous system and apparently can damage the cells making up the blood-brain barrier that protects the brain from many harmful chemicals. (reference)
Exposure to lead in the home occurs via two routes: the ingestion and/or inhalation of lead dust from paint and the consumption of water contaminated with lead.
Lead paint is present on an estimated 30 to 40 million houses in the United States. Most homes built before 1970 contain heavily leaded paint. Some homes built as recently as 1978 may also contain lead paint. This paint could be on window frames, walls, the outside of homes, or other surfaces. Lead comes from paint chips, plaster chips, and windowsills and other woodwork in old houses painted with lead-based paint. Old lead-based paint is the most significant source of lead exposure in the U.S. today. Harmful exposures to lead can be created when lead-based paint is improperly removed from surfaces by dry scraping, sanding, or open-flame burning.
Lead-contaminated drinking water is most often a problem in homes that are either very old or very new. Up through the early 1900s, it was common practice to use lead pipes for interior plumbing. Also lead piping was often used for the service connections that join residences to public water supplies. Copper pipes have replaced lead pipes in most residential plumbing. However, the use of lead solder with copper pipes is widespread. Experts regard this lead solder as the major cause of lead contamination of household water in U.S. homes today. Lead concentrations in drinking water can be also be elevated if your home has faucets or fittings of brass which contains some lead. The most common cause of lead getting into drinking water is corrosion, a reaction between the water and the lead pipes or lead solder. Lead can leach into the water from the joints or from lead pipes. Dissolved oxygen, low pH (acidity), and low mineral content in water are common causes of corrosion. One factor that increases corrosion is the practice of grounding electrical equipment, such as telephones, to water pipes. Any electric current traveling through the ground wire will accelerate the corrosion of lead in the pipes. Most well and city water does not usually contain lead. Water can pick up lead inside the home from household plumbing that is made with lead materials. The only way to know if there is lead in drinking water is to have it tested. Contact the local health department or the water supplier to find out how to get the water tested.
New brass faucets and fittings can also leach lead, even though they are "lead-free". Scientific data indicate that the newer the home, the greater the risk of lead contamination. Lead concentrations decrease as a building ages. This is because, as time passes, mineral deposits form a coating on the inside of the pipes (if the water is not corrosive). This coating insulates the water from the solder. But, during the first five years, before the coating forms, water is in direct contact with the lead. More likely than not, water in buildings less than five years old has high concentrations of lead contamination.
Have you home inspected for lead piping. If you suspect your water contains lead have it tested by a qualified laboratory. Lead piping should be removed. Flush your pipes before drinking. Anytime the water in a particular faucet has not been used for six hours or longer, flush your cold water pipes by running water until it becomes as cold as it will get. The more time water has been sitting in your home's pipes, the more lead it may contain.
Leave lead-based paint undisturbed if it is in good condition. Do not sand or burn off paint that may contain lead. Individuals have been poisoned by scraping or sanding lead paint because these activities generate large amounts of lead dust. Do not burn painted wood since it may contain lead. Do not remove lead pain yourself. Hire a qualified lead-abatement contractor to remove contamination. Keep areas were lead dust occurs (i.e. windowsills) clean and dust-free.
See also: Lead additives, Lead as toxic element, Beethoven, Home lead poisoning, Lead in history, Lead letter, Occupational disease, Toxic effects, Toxicology