One in three children around the world have concentrations of lead in their blood at levels likely to cause significant long-term health damage, new research has found.
About 800 million children and young people under the age of 19 are likely to have blood levels of lead at or above 5 micrograms per decilitre (5μg/dl), according to the report. There is no safe level for lead exposure, according to the World Health Organization, because even at very low concentrations it operates as a dangerous toxin, but levels above 5μg/dl are regarded by the US Centers for Disease Control as a cause for action. Lead is a potent neurotoxin and high exposure can kill, while lower levels cause symptoms ranging from pain, vomiting and seizures to developmental delay, mental difficulties and mood disorders. The lower levels can also cause children to be born prematurely. Exposure at the levels studied is likely to cause reductions in cognitive ability, higher levels of violence and long term health impacts such as cardiovascular disease, according to the researchers.
Children are particularly vulnerable to lead exposure because it damages the developing brain and nervous system, building up over time, and the impacts do not show immediately. Lead mimics calcium in the bones, building up in people’s bodies and causing damage to other vital organs, including the kidneys, heart and lungs. Lead at 5μg/dl of blood is likely to wipe about 3-5 points from a child’s IQ score, and at the levels found in the Unicef report could double the level of violence in society. It is also likely to increase the risk of cardiovascular disease, as about 900,000 deaths a year are already linked to lead poisoning. 30 academic studies had linked elevated lead levels to people’s propensity for violent behaviour, providing enough corroboration for scientists to make a strong association between continuing lead contamination and its likely impacts on violence.
“This is an absolutely shocking figure,” said Nicholas Rees, policy specialist at Unicef and author of the report. “We have known for so long about the toxic nature of lead, but we have not known how widespread it is, and how many children are affected.”
Richard Fuller of Pure Earth, an NGO that collaborated with Unicef on the report, said people were less aware of the damage caused by lead, after campaigns to remove the toxin from many common uses in developed countries decades ago.
“We did a terrific job of taking lead out of gasoline, but the use of lead has plateaued after falling in the 1970s and 80s,” he said. Fuller said that while the levels of lead might seem small, across populations the damage was significant. “It means double the number of people who are intellectually impaired,” he said. “It is definitely not a trivial issue.”
In the US, children living in poorer households and dilapidated accommodation have been found to be at higher risk. In the UK, about 200,000 children are likely to be affected, according to Unicef.