Leaded gasoline was a larger emission source of the toxic heavy metal lead than mining in South America – even though the extraction of metals from the region’s mines historically released huge quantities of lead into the environment. Researchers from the Paul Scherrer Institute PSI and the University of Bern have discovered evidence of the dominance of leaded gasoline based on measurements in an ice core from a Bolivian glacier. The scientists found that lead from road traffic in the neighbouring countries polluted the air twice as heavily as regional mining from the 1960s onwards. The study is to be published in the journal Science Advances on 6 March 2015.
Record of anthropogenic lead emissions over the past 2,000 years in the Bolivian Altiplano. Shown are lead enrichment factors (EFs) compared to the regional background, reconstructed based on an ice core from the Illimani glacier. Before the use of leaded gasoline (period AD 0–1960), lead emissions from mining activities were dominant, especially during periods of the pre-Colombian cultures Tiwanaku/Wari and the Incas, the colonial era and with the increasing industrialisation in the 20th century (brown, blue). Emissions from leaded gasoline were primarily responsible for the significant increase after 1960 (green). Picture: Paul Scherrer Institute.
....The researchers’ analyses also revealed that the anthropogenic, i.e. man-made, lead emissions prior to 1960 primarily entered the atmosphere via mining activities. The pollution was particularly severe during periods of the pre-Colombian cultures Tiwanaku/Wari and the Incas, the colonial era and with the increasing industrialisation of the 20th century.
...The study once again highlights the importance of the ban on leaded gasoline for the environment and human health. If inhaled, lead can enter the bloodstream and ultimately the brain, where it poisons nerve cells. Leaded gasoline has already proven to be a key source of lead emissions in previous studies. “We now show that this is also the case in a region in which mining with its heavy lead emissions has been practiced intensively for millennia,” says Margit Schwikowski, co-author and head of the study and the Analytical Chemistry Group in the Laboratory for Radiochemistry and Environmental Chemistry at PSI.