Tracing dust sources using stable lead and strontium isotopes in Central Asia

Nitika Dewan, Brian J. Majestic, Michael E Ketterer, Justin P. Miller-Schulze, Martin M. Shafer, James J. Schauer, Paul A. Solomon, Maria Artamonova, Boris B. Chen, Sanjar A. Imashev, Gregory R. Carmichael

Research output: Chapter in Book/Report/Conference proceedingChapter

2 Scopus citations

Abstract

From 1960 to 2014, the Aral Sea's surface area has receded about 90% in size from 68,000 km2 to 8,444 km2. Consequently, newly exposed sediments are resuspended by the wind and are now a source of atmospheric particulate matter in Central Asia, which may have an impact on human health and climate. In this study, strontium (Sr) and lead (Pb) stable isotopic ratios, along with other elemental compositions, are used to determine if the Aral Sea sediments are an important source of air pollution to Central Asia. Ambient particulate matter with aerodynamic diameter <10 μm (PM10) samples were collected every other day and included dust and non-dust events at the Bishkek and LIDAR (in Teploklyuchenka) in Kyrgyzstan. Soil samples also were collected in the vicinity of the air sampling sites, resuspended, and sized as PM10 for chemical analysis. The average 87Sr/86Sr ratio for the Aral Sea sediments was 0.70992 (range, 0.70951 - 0.71064), which is less radiogenic than the surface soils in Kyrgyzstan showing an average ratio of 0.71579 (range, 0.71448 - 0.71739). In contrast, the airborne PM10 collected in Kyrgyzstan had an average 87Sr/86Sr ratio of 0.71177 (range, 0.70946 - 0.71335), which is between the two ratios, indicating a possible mixture of sources. However, no differences in Sr ratios were observed between dust and non-dust events, which implies that the impact of Aral Sea sediments on the sampling sites is minimal. The element enrichment factors and stable Pb isotope ratios are employed to further understand the source of PM10. Airborne PM10 are characterized by enrichments in elements like As, Cd, Cu, Mo, Pb, and Zn at both sampling sites. The mean (K/Pb) ratio for aerosols is ~ 45 and for soils is ~800, which suggest that the aerosols contain a significant fraction of anthropogenic source of airborne Pb in Kyrgyzstan. 208Pb/206Pb ratios are higher for aerosols compared to the Kyrgyzstan soils and Aral Sea sediments also suggesting that Pb is most likely present due to anthropogenic sources.

Original languageEnglish (US)
Title of host publicationTrace Materials in Air, Soil, and Water
PublisherAmerican Chemical Society
Pages79-98
Number of pages20
Volume1210
ISBN (Print)9780841231092
DOIs
StatePublished - 2015
Externally publishedYes

Publication series

NameACS Symposium Series
Volume1210
ISSN (Print)00976156
ISSN (Electronic)19475918

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)

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    Dewan, N., Majestic, B. J., Ketterer, M. E., Miller-Schulze, J. P., Shafer, M. M., Schauer, J. J., Solomon, P. A., Artamonova, M., Chen, B. B., Imashev, S. A., & Carmichael, G. R. (2015). Tracing dust sources using stable lead and strontium isotopes in Central Asia. In Trace Materials in Air, Soil, and Water (Vol. 1210, pp. 79-98). (ACS Symposium Series; Vol. 1210). American Chemical Society. https://doi.org/10.1021/bk-2015-1210.ch004