Lead is an environmental hazard arising from industrial, natural and domestic sources. It is toxic when inhaled or ingested. Lead is a "stealth poison" that can cause hyperactivity, attention deficit disorder, learning disabilities and developmental harm - in extreme cases leading to comas and death - but has few or no immediate symptoms. Children under six, including foetuses, are especially vulnerable.
The most common lead hazards for children are airborne lead dust, leaded soil, loose chips and chewable surfaces painted with lead-based paint. Children are particularly sensitive to lead because their intestines absorb the metal in greater quantities that those of adults, and their nervous systems are still developing. Acute encephalopathy, a very serious manifestation of lead poisoning in young children, is followed by permanent neurological consequences in at least 25% of cases. Common symptoms of early lead poisoning include fatigue, abdominal pain and mental disorders. Even after successful removal of lead from the body, such children are still at high risk from recurrent poisoning when they return home.
Because it is easily shaped, melted and moulded, lead was widely used by the Romans for plumbing, stapling masonry together, casting statues and manufacturing many kinds of utensils. All these uses presumably contributed to the chronic poisoning of Rome's peoples. Adding to the toxic hazard, Romans used lead vessels to boil and concentrate fruit juices and preserves. Fruits contain acetic acid, which reacts with metallic lead to form lead acetate, a compound once known as "sugar of lead." Lead acetate adds a pleasant sweet taste to food but causes lead poisoning – an ailment that is often fatal and, even in mild cases, causes debilitation and loss of cognitive ability.
Lead was a common ingredient in paint until the 1970s and 1980s. Now it is mostly banned or only found in paints with special applications.
Common sources of lead in and around the home come from moving parts of windows and doors that can make lead dust and chips; lead-based paint on woodwork and external fittings; soil next to the exterior of buildings that have been painted with lead-based paint or has been contaminated with leaded petrol dust near busy streets; drinking water (pipes and solder); adults who may bring lead dust home from work on skin, clothes and hair, coloured newsprint and car batteries; highly glazed pottery and cookware from certain countries; and removing old paint when refinishing furniture or renovating old houses (even when the paint is removed the wood may contain lead which is released on sanding).
In pre-war France, buildings paint containing acid-soluble white lead was often used, as it gave improved coverage and protection against humidity and fungal attack. In 1948 it was banned, but the old paint was not removed. Now it seems most prevalent in the poor and run-down parts of Paris, and is chipping and forming toxic lead dust. Small children inhale or swallow the dust (lead dust is so fine that is passes through ordinary vacuum cleaners). Lead is regarded as the greatest environmental threat to children in French cities. Since screening in just some districts of Paris and some other cities began there have been more that 2,500 cases of lead poisoning, including 100 in 1993. Ffr 14 million has been allocated to a nationwide campaign to detect and prevent lead poisoning.
In the USA, about three out of every four pre-1978 buildings have lead-based paint.
In 1998, the US Centers for Disease Control and Prevention issued a report stating that 4.4 percent of American children (890,000) between the ages of 1 and 5 have toxic levels of metal lead in their blood. Toxic levels, or what the report calls "levels of health concern," mean generally that the children affected are developing with a diminished intellectual capacity, reducing their IQ and mental abilities. Dr Erik Millstone of the Science Policy Research Unit at Sussex University produced a report in 1997 which estimated that the intelligence of one in 10 British children under six had been diminished by exposure to lead. It demonstrated the widespread danger from old lead paint and lead pipes. Research by a Dr Neil Ward at Surrey University in 1998 linked exposure to high levels of lead pollution to behavioural problems in teenagers. Dr Ward looked at lead levels as part of a study into the effects of nutrition on behaviour in a group of 100 children and teenagers.