摘要:
南亚排放的持久性有机污染物(POPs)可随大气传输到青藏高原,然而POPs在高原多介质间的迁移与分配尚不清晰。本研究利用三级逸度模型对4种POPs(六六六α-HCH,滴滴涕p,p'-DDT,菲Phe和苯并芘BaP)在纳木错流域的迁移与归趋进行了模拟。结果表明,大气沉降是该区域污染物的主要输入过程,而降解损失则是主要的输出途径。就最终归趋而言,土壤是POPs在纳木错流域的重要储库,其存储了大于50%的POPs。此外,湖水和沉积物分别对α-HCH和PAHs具有较强的存储能力。灵敏度分析的结果表明,环境温度、大气中POPs的浓度及其理化性质是影响POPs在环境中分布的关键参数。本研究明确了纳木错流域不同POPs的迁移方向和归趋特征,这将为青藏高原生态安全评估提供科学依据。
Abstract:
Persistent organic pollutants (POPs) emitted from South Asia can be transported to the Tibetan Plateau (TP), driven by favorable atmospheric circulation; however, their transfer between different media (air, soil, water, sediment etc.) and their final fate in the TP are unclear. In the present study, a level III fugacity model was applied to simulate the exchange fluxes and concentration distributions of four POPs (α-HCH, p,p'-DDT, Phe and BaP) in Nam Co Basin. The results showed that atmospheric deposition is the main input process for POPs into this region, and degradation is the main elimination pathway. Soil is the major sink of POPs, accounting for more than 50% of their total reserves. In addition, lake water and sediment have a certain storage capacity for α-HCH and polycyclic aromatic hydrocarbons, respectively. Sensitivity analysis showed that the concentrations of POPs in the air, their physicochemical properties, and air temperature, are key parameters affecting the environmental behavior and distribution of POPs. In conclusion, the direction of transfer, the fluxes amounts, and the final fate of different POPs among different media in Nam Co were successfully quantified in the model, thus contributing to a scientific basis for ecological safety assessments within the TP region.
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