1296 / 2019-08-08 23:59:34

The combined effects of climate change and pollution emissions on the accumulation of pollutants in TP lakes

15、冰冻圈科学 > 专题5：冰冻圈大气污染的来源、迁移转化过程和影响

The combined effects of climate change and pollution emissions on the accumulation of pollutants in TP lakes

Tingting Zhu,1,4 Xiaoping Wang,1,2,4 Hai Lin,1 Chuanfei Wang,1,2 and Jiao Ren1,3

1Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China
2CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing, 100101, China
3Research Institute of Transition of Resource-Based Economics, Shanxi University of Finance and Economics, Taiyuan 030006, Shanxi, China
4University of Chinese Academy of Sciences, Beijing 100049, China

Under global warming, the glaciers in the Tibet Plateau (TP) have undergone severe contraction (except for the Karakorum region), resulting in secondary release of pollutants stored in glaciers. The released pollutants can transport and eventually sink in the lakes supplied by melting glaciers. At present, there is no search about climate change and pollution emissions’ combined effects on the accumulation of pollutants in TP lakes. As lake core can effectively record the climate change and historical emissions of pollutants, therefore, we selected the semi-enclosed proglacial lake Qiangyong in the southern of TP as the research object. The climate change and pollution history of Qiangyong Glacier Basin during the last two hundred years (1836-2014, 210Pb and 137Cs dating) were reconstructed by measuring the elements, grain-size, total organic carbon, black carbon (BC) and mercury in the lake core samples. The experimental results show that research area has been warming for nearly two hundred years, especially in the 1950s, when the glaciers melting caused the lake sedimentation rate to reach the maximum (0.12g/cm2yr). The concentrations of BC, lead and mercury in the lake core were 2.61-8.77 mg/g, 20.36-37.85μg/g and 9.37-101.73 ng/g, respectively. In addition, the concentrations and fluxes of BC, lead and mercury increased rapidly in the 1950s. To further quantitatively estimate the contribution of glacial melting and human activities to the accumulation of pollutants in lakes, a positive matrix factorization model (PMF) was used. Corresponding to the high accumulation of pollutants in 1980s and 21c, the PMF model estimates that the contribution of glacial melting and anthropogenic influences to the accumulation of pollutants in sediments is 95.46% and 91.69%, respectively. In particular, the contribution of weathering in the 1950s reached 61.33%. The comprehensive analysis shows that the contribution of pollutants release from glaciers and pollution emissions to the water environment is important.

Keywords: Tibetan Plateau; climate change; pollution emissions; proglacial lake;