可可西里特拉什湖中微塑料污染特征、来源和生态风险

Characteristics,sources and ecological risks of microplastics in Telashi Lake in Hoh Xil

微塑料作为一种新型污染物,近年来已成为环境科学的研究热点.为探究青藏高原无人环境中的微塑料污染,以可可西里自然保护区特拉什湖作为研究区域,分析了湖滨沉积物中微塑料的丰度分布、物理形貌和成分特征.在此基础上,讨论了微塑料的潜在来源,并利用污染负荷指数(PLI)模型和风险指数(H)模型评估了微塑料的生态风险.结果表明,特拉什湖沉积物中微塑料丰度范围为39.58~247.92 n·m^(-2),平均丰度为(107.08±101.34)n·m^(-2).这一结果可作为现阶段微塑料污染研究的自然背景参考值.纤维占微塑料总数的79.49%,透明和小粒径(<1 mm)的微塑料占很大比例,确定的主要聚合物是聚酯(51.28%).纺织品是特拉什湖微塑料的主要来源,可能来自特拉什湖以西,通过大气环流长距离运输至该区域.生态风险评估模型显示,特拉什湖的微塑料污染负荷较轻;尽管少数点位的生态风险指数较高,但总体上该区域的微塑料污染仍处于较低水平.

As a kind of emerging pollutant,microplastics(MPs)have recently become a research hotspot in environmental science.In order to understand the status of microplastic pollution in the uninhabited environment of the Qinghai-Tibet Plateau,the abundance,physical morphology,and composition characteristics of MPs were investigated in the lakeshore sediments of Telashi Lake in Hoh Xil Nature Reserve.Based on which,the potential sources of MPs were discussed and the ecological risk were evaluated by using the Pollution Load Index(PLI)model and the Risk Index(H)model.The results indicate that the microplastic abundance in the lakeshore sediments ranges from 39.58 to 247.92 n·m^(-2),with an average value of(107.08±101.34)n·m^(-2).This can be taken as the background value for the current microplastic pollution in this area.Fibers take up to 79.49%of the total MPs in number.And transparent and small-sized(<1 mm)MPs contribute significant proportions.The predominant polymer is polyester(51.28%).Textiles are the main source of MPs in Telashi Lake,possibly from the west of Telashi Lake through long-distance atmospheric transportation.The ecological risk assessment shows that the pollution load of MPs in Telashi Lake is relatively low.Although a few spots present high value in ecological risk index,as a whole,the microplastic pollution in the area is in the low level.