Lead used in petrol decades ago still pollutes London’s air: study

The wrong combination of fuel and air can lead to uneven combustion of fuel inside an automobile engine cylinder, causing the engine to produce a thud sound, commonly known as ‘engine knocking’. In the early twentieth century, tetraethyl lead was adopted as an antidock additive in fuels to avoid this.

However, the harmful effects of lead consumption were not known until the 1920s, when the practice gained wide acceptance. In the 1970s and ’80s, there was growing awareness of the harmful effects of lead on the environment and health, and this led to the illegal and phased out use of lead as an anticock additive in fuels in most developed countries. Gaya.

Years after it was phased out in most countries (it is currently legal in only six countries: Algeria, Iraq, Yemen, Myanmar, North Korea and Afghanistan), lead from automobile fuel still remains a serious health risk. . This is because lead accumulates in the soil or finds its way into water bodies from the exhaust of the fuel. The lead stored in the soil gets carried away in the air and finds its way into the pleural tract. Lead in water can be used for irrigation or can be ingested directly.

In a recent study, researchers from the UK and the European Union found that lead from a fuel banned nearly two decades ago (around the same time it was banned in India) is still prevalent in London’s air today. The study was done by comparing the dominant isotopic signatures on both space and time.

To account for spatial variation, road dust and top soil samples were combined with the samples collected from the terraces. This was done for the years 2014–2018 and then supplemented with lead isotope data from different years from the 1960s to the 2000s.

Airborne Particle Sampling (Eleanor Resonals) at Marylebone Road

The main findings from the study are that there was little difference in lead levels in both spatial and temporal estimations, that is, airborne samples were similar to soil and road dust; And that the material has remained largely unchanged over the past decade.

Lead levels in London’s air fell sharply from 500–600 ng/m to 300 ng/m in the 1980s, a decade when “nearly 7000 tonnes were emitted in road traffic exhaust in the UK”, before this further dropped to 20 ng/m³. 2000 – but the concentrations measured in 2018 were 8-10 ng/m³.

According to the study, around 800 kilograms of lead contributed to London’s air by recirculating or re-suspending contaminated dust. In addition, the researchers found little inter-annual variation, which led them to conclude that the burning of coal in the surrounding area could not be attributed to lead contamination.

A similar study conducted for So Paulo, Brazil also reached a similar conclusion: the dominant isotopic signatures from the aerosol samples were “primarily derived from vehicular exhaust and regurgitation of traffic dust.”

This has serious consequences, especially for children, in whom it can cause permanent brain damage. Exposure to lead in pregnancy can lead to stillbirth and miscarriage, with the World Health Organization stating that there is no safe limit for lead consumption.

“Atmospheric lead in London has reached a baseline that is difficult to push further down with current policy measures. We need more research to identify the impact of current air concentrations – even if those data exceed air quality targets.” Let’s do it – on human health, and to find the best way to rid London of lead’s legacy for good,” said lead author Dr Eleanor Resongels. of the study, in a press release.

-The author is a freelance science communicator. (Match[at]Ritwik[dot]com)


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