Lead isotopes combined with a sequential extraction procedure for source apportionment in the dry deposition of Asian dust and non-Asian dust

Lead isotopic compositions were determined in leachates that were generated using sequential extractions of dry deposition samples of Asian dust (AD) and non-Asian dust (NAD) and Chinese desert soils, and used to apportion Pb sources. Results showed significant differences in 206Pb/207Pb and 206Pb/204Pb isotopic compositions in non-residual fractions between the dry deposition samples and the Chinese desert soils while 206Pb/207Pb and 206Pb/204Pb isotopic compositions in residual fraction of the dry deposition of AD and NAD were similar to the mean 206Pb/207Pb and 206Pb/204Pb in residual fraction of the Alashan Plateau soil. These results indicate that the geogenic materials of the dry deposition of AD and NAD were largely influenced by the Alashan Plateau soil, while the secondary sources of the dry deposition were different from those of the Chinese desert soils. In particular, the lead isotopic compositions in non-residual fractions of the dry deposition were homogenous, which implies that the non-residual four fractions (F1 to F4) shared the primary anthropogenic origin. 206Pb/207Pb values and the predominant wind directions in the study area suggested that airborne particulates of heavily industrialized Chinese cities were one of the main Pb sources. Source apportionment calculations showed that the average proportion of anthropogenic Pb in the dry deposition of AD and NAD was 87% and 95% respectively in total Pb extraction, 92% and 97% in non-residual fractions, 15% and 49% in residual fraction. Approximately 81% and 80% of the anthropogenic Pb was contributed by coal combustion in China in the dry deposition of AD and NAD respectively while the remainder was derived from industrial Pb contamination. The research result proposes that sequential extractions with Pb isotope analysis are a useful tool for the discrimination of anthropogenic and geogenic origins in highly contaminated AD and NAD. •Sequential extractions of Pb were applied for AD, NAD, and Chinese desert soils.•Lead isotopic compositions were analyzed in five-step geochemical fractions.•Geogenic particulates in AD and NAD originated from the Alashan desert soil.•Pb bound to non-residual fractions of AD and NAD originated from coal emissions.•Lead isotope with sequential extractions was effective for source identification and apportionment. Pb isotope analysis with a sequential extraction procedure is a useful tool for the discrimination of anthropogenic and geogenic origins in dry deposit