Collaborative Research: Collaborative Research: Anthropogenic Impact on the Geochemical Cycle of Lead (Pb) since the Industrial Revolution in Asia

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Lead (Pb) is a highly toxic heavy metal with negative and irreversible effects on children’s development and behavior, and also with a number of health effects in adults. Even though Pb has been used for millennia, it was not until the Industrial Revolution and later when leaded gasoline was introduced in Europe and North America in the 1920s that Pb from human activities surpassed its natural and preindustrial contribution by about two orders of magnitude. Anthropogenic Pb emissions have decreased in North America and Europe since the 1970s with the introduction of emission controls and after leaded gasoline was phased out. However, this has not been the case in Asia. Polar and high-altitude glaciers preserve records of climate and environmental changes, and thus allow to study past and present atmospheric Pb levels. This project will determine the sources of Pb found in ice cores from Tibet and the Himalayas. It will provide information to policy makers to develop strategies to reduce Pb emissions. The results will also be shared through classes at the undergraduate and graduate levels and to the general public by outreach activities.To understand the role of human activities on the Pb geochemical cycle from pre-industrial times to the present in Asia, a region that is currently undergoing a number of drastic environmental changes and is poorly studied, the isotopic composition of Pb in ice cores from three different sites, the Guliya ice cap in northwestern Tibet, the Puruogangri ice cap in central Tibet and the Dasuopu glacier in the Himalayas will be reconstructed. The Pb isotope ratios will allow: (1) the establishment of a pre-industrial Pb isotopic background in Asia; (2) the determination of how human activities have modified the Pb geochemical cycle after the Industrial Revolution in Asia; and (3) the assessment of whether Pb from human activities in North America have reached Asia.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.