Study of North Atlantic Ocean reveals decline of leaded petrol emissions

A new study of lead pollution in the North Atlantic provides strong evidence that leaded petrol emissions have declined over the past few decades. For the first time in around 40 years, scientists have detected lead from natural sources in samples from this ocean. In the intervening period, the proportion of lead in the ocean from manmade sources, most importantly leaded petrol emissions, had been so high that it was not possible to detect any lead from natural sources. This is the first time since similar studies began in the late 1970s that natural lead in the ocean has been at an observable level. Dr Tina Van de Flierdt Department of Earth Science and Engineering Trace metals such as lead are continuously recycled on land, in the ocean and in the atmosphere, and are important barometers that help scientists to understand planetary processes. Scientists are particularly keen to monitor levels of lead from natural sources, such as windblown dust, and lead from manmade sources, such as burning coal, to determine the impact of industrialisation on the planet and levels of pollution. A team of scientists from Imperial College London, and their collaborators, analysed the chemistry of seawater samples collected from across the tropical North Atlantic in 2010 and 2011.