One-century sediment records of heavy metal pollution on the southeast Mongolian Plateau: Implications for air pollution trend in China

Historical records of heavy metals from remote areas are important for assessing temporal pollution trends of the regional atmosphere. Based on comparison analyses of heavy metals, Pb isotopes, and total carbon in sediment cores from two relatively remote lakes on the southeast Mongolian Plateau, atmospheric heavy metal pollution trends during similar to 1900-2016 were reconstructed. The current anthropogenic fluxes of Zn, Cd and Pb in the region are 11.7, 0.104 and 2.44 mg m(-2) yr(-1), respectively, close to those in Lake Sayram in West China, but lower than most other records in China. Anthropogenic metal fluxes and Pb-206/Pb-207 ratios suggest that (1) before similar to 1950 atmospheric metal pollution was negligible in the region; (2) since similar to 1950, the pollution became detectable but was relatively slight until similar to 1980, corresponded with the beginning of socio-economic development after the foundation of China in 1949 and the rapid development after the Reform and Opening-up in 1978; and (3) since similar to 2000, atmospheric Pb stopped increasing because of the phasing out of leaded gasoline. Based on comparison and fitting analyses with other sediment records, a similar four-stage evolution picture of atmospheric heavy metals in China over the last century was uncovered. This study indicates rapid increase trends of atmospheric heavy metals in China since similar to 1980 associated with economic development. (C) 2018 Elsevier Ltd. All rights reserved.