Perjantai 31.7.2020 klo 16:55 - Mikko Nikinmaa
The first large-scale lead poisoning dates back to Roman times. Many historians are of the opinion that the downfall of Roman empire was partly due to large-scale lead poisoning. The drinking water was lead to Rome and some other big cities in lead aquaducts, with the consequence that some lead dissolved in water and was drunk. The amount of lead this obtained was enough to cause neurotoxicity.
The second time that concerns of common lead poisoning reached news was when car traffic using leaded fuel increased markedly in industrialized countries. This led to quite rapid phasing-out of lead in petrol in 1989’s. Lead was also an important component of paints in, e.g. kitchenware and toys, whereby everyone but especially children were exposed to toxic lead concentrations. Because of this, also lead-containing paints have been banned. As a result of the bans of lead in fuels and paints the lead levels in the blood of children in industrialized, rich countries has decreased to values which do not cause observable toxicity.
The toxicity of lead is especially harmful to children. Lead is primarily a neurotoxicant. It disturbs brain development. If brain development of a child is disturbed, the disturbance persists for the rest of the life. Lead-poisoning decreases the intelligence, increases aggressiveness and generally makes the affected people lethargic. It also decreases the attention time span; it has been estimated that a quarter of ADHD cases would, in fact, be caused by lead poisoning. There are also associations between lead poisoning an hearing acuity, which suggests that lead exposure may cause speech and language handicaps.
Above the level of 5 micrograms per decilitre (µg/dL), lead causes the intelligence, behaviour and learning problems as estimated by the American CDC (Center of Disease Control and Prevention) and WHO (World Health Organization), although WHO points out that there is no safe level of exposure. If the 5 µg/dL concentration is taken as the limit, a third of world’s children have exposure, which causes life-long effects. As children in industrialized countries do not normally have these high lead levels in their blood, this is another problem between poor and rich countries.
We in industrialized countries have become aware that resources, such as metals, should be recycled. If this is done responsibly, it helps a lot for making the resource use in the world sustainable. However, many of the recycling companies are not in the business to help the earth but to make money. As a result, the “recycling” is done in poor countries, and no precautions, which would be required in Europe and North America, are followed. Because of this, recycling lead-acid car batteries has become the single most important source of lead exposure for children in poor countries. Thus, one should demand that recycling must be done in the commercial area, where the product is used. In addition to car batteries, lead-containing paints and toys containing lead are still common in poor areas.
A more detailed account of lead problem in children is the report by UNICEF and Pure Earth: The Toxic Truth: Children’s Exposure to Lead Pollution Undermines a Generation of Future Potential, which is available at https://www.unicef.org/reports/toxic-truth-childrens-exposure-to-lead-pollution-2020