Toxic lead from gasoline that was banned 20 years ago is still lingering in the air in London, according to a study, with researchers saying the legacy of leaded fuels is likely to hang over most cities.
Although the levels are much lower than their peak in the 1980s, they remain well above natural background levels. Lead is extremely toxic and there is no safe amount of exposure. It is of particular concern to children because it damages their developing brains and their ability to learn.
Lead was added to fuels in the UK from the 1930s and phased out over the decade until 1999. The metal was deposited on urban surfaces and soils for many decades and it is believed to ‘it is repeatedly blown back into the air by winds, traffic, and construction and levels no longer drop.
The researchers said the work illustrated how pollutants could stay in the environment for many years after being banned. Other problems include persistent organic pollutants such as the long-banned DDT pesticide.
“The key message of [our study] is that lead in gasoline is here to stay, and it is having an impact today, ”said Professor Dominik Weiss of Imperial College London. “For more than 30 years, the same pollutant has been recycled.
Lead from long-banned fuels has also been identified in Shanghai, China, and São Paulo, Brazil, and Weiss said it was likely to contaminate many cities. One in three children in the world has blood lead levels that can cause significant damage to long-term health, according to a study by Unicef.
The new study, published in the journal Proceedings of the National Academy of Sciences, found that 32 to 43% of lead in London’s air was originally from leaded fuels. Lead atoms can have different numbers of neutrons and the ratio of these isotopes is very distinct in lead fuels.
This helps distinguish the source of the metal from other sources, such as burning coal, industry, brake and tire dust, and old paint. Researchers found similar lead levels in roadside and rooftop samples between 2014 and 2018, indicating that pollution remained in the air across the city.
Lead levels in the air are now just 2% of the ’80s peak, but it’s still 100 times higher than natural levels, says Weiss. Research in the United States has shown that people’s blood lead levels are linked to airborne levels of the pollutant, suggesting that they are ingesting lead from the air.
Land contaminated with lead can be made safer by placing clean soil on top, which also prevents children from ingesting lead when playing. This approach reduced lead levels in the blood of children in New Orleans, United States.
“Soil remediation can be a great solution, focusing on places where children are exposed, such as playgrounds and gardens,” said Eléonore Resongles, University of Montpellier, France, and member of the research team. “With a contamination map, you can identify hot spots. “
Professor David Phillips, University of Southampton, who was not involved in the study, said: ‘The key message is that pollutants such as lead do not go away when they are no longer under. the projectors. Lead is still a problem at many old industrial sites and associated with historic mining, as well as from household sources such as lead pipes and old paint.
“The main concern is the exposure of young children – there is good evidence for adverse neurodevelopmental effects at low doses. The extent of the problem is difficult to assess, but is clearly likely to affect families living near roads with historically high traffic volumes. “
A government spokesperson said: “Nationally, air pollution levels have declined dramatically since 2010, but we know there is still a long way to go to tackle harmful emissions given their impact. inherited.
“This is why we are setting new legally binding targets for particulate matter pollution in our draft environment law and we are building on our clean air strategy to accelerate measures to clean our environment.” air. “