Investigation of 200-Year Anthropogenic Effects in a Representative Peatland in the Xinjiang Altay Mountains, Northwestern China

Abstract

Studies show that black carbon (BC) and polycyclic aromatic hydrocarbons (PAHs) are convincing signs of anthropogenic activities. The main objective of the present study is to analyze BC, PAHs, and δ 13 C BC deposition in Heihu peatlands. 137 Cs and 210 Pb dating methods were used to establish sedimentary core ages. Our results reveal concentrations of BC and PAHs in Heihu peatlands were 11.71 - 67.5 mg·g -1 and 168.09 - 263.53 ng·g -1 , respectively. Combining with δ 13 C BC of BC and molecular diagnostic ratios of PHAs, The δ 13 C BC value ranged from 31.37 - 26.27‰, with an average of -29.54‰, revealed that the BC mainly comes from biomass combustion. Moreover, The ratios of low- and high-molecular weight PAHs, BaA/(BaA + Chr), Flt/(Flt + Pyr) and Ant/(Ant+Phe) exceeded 0.35, 0.5 and 0.1, respectively. It revealed that PAHs pollutants originated from the combustion of biomass and fossil fuel burning. Based on the performed analyses and obtained results, the human activities in the studied peatland can be divided into three eras, including 1832 – 1910, 1910 - 1980, and after 1980. Moreover, since the 1980s industrial transportation and tourism also have impact on BC and PAHs emission, migration, and deposition in the Altay Mountains. Moreover, with the implementation of environmentally friendly policies, the concentration of pollutants tended to decrease after the 1980s. The obtained results are consistent with industrial development in China. The results of this study not only reveal the influence of anthropogenic activities on the sedimentary characteristics of peatlands in the Altay Mountains, but also provide an important theoretical basis for the conservation of fragile mountain peat bogs.

Keywords: peatlands, anthropogenic impacts, Polycyclic aromatic hydrocarbons, Black carbon, Altay Mountains.