多年冻土中持久性有机污染物的环境赋存与行为

Occurrence and environmental behavior of persistent organic pollutants in permafrost regions under global climate change

关键词:  多年冻土  持久性有机污染物  全球气候变化  二次释放  迁移机制  生态环境影响  高海拔地区  极地地区

Key words:  permafrost  persistent organic pollutants (POPs)  global climate change  secondary emissions  migration mechanisms  ecological and environmental impact  high-altitude regions  polar regions

摘要:

在全球气候变化背景下，多年冻土的快速退化已引发持久性有机污染物（POPs）储存与迁移模式的显著变化。POPs作为一种半挥发性、环境持久性和生物累积性的污染物，广泛存在于极地和高海拔多年冻土区。多年冻土作为重要的“储存库”，在气候变暖推动下逐渐融化并释放POPs，通过大气、土壤和水体迁移进入环境循环，形成“二次释放”现象。文章综述了多年冻土中POPs的来源、传输途径、赋存特征及其在气候变化背景下的迁移和释放机制，系统分析了POPs的环境行为与变化特征。研究表明： POPs的释放与多年冻土的退化息息相关，其来源和分布特征因区域气候条件和环境状况的差异而异；此外，青藏高原、帕米尔高原等高海拔地区因邻近污染源的影响，POPs的分布特征与极地多年冻土区显著不同。未来研究需进一步关注POPs在多年冻土区的动态演变过程，包括对气候驱动因素与多年冻土融化的精细化解析，并加强区域与全球监测网络的构建；同时，通过多学科合作和政策支持，为全球污染物治理和气候变化应对提供科学依据。

Abstract:

Background, aim, and scope The rapid degradation of permafrost, driven by ongoing global warming, has become a significant concern, especially in high-altitude and polar regions. The warming of permafrost and glacier melting is causing the release of persistent organic pollutants (POPs) that have been historically stored in these areas. POPs, a class of toxic contaminants, pose serious risks to human health and ecosystems. As climate change accelerates, the secondary emission of these pollutants from permafrost and glaciers is becoming a growing environmental issue. This review aims to explore the secondary emissions and environmental migration of POPs resulting from permafrost degradation and glacier retreat under climate change. The goal is to understand how these changes affect the behavior and distribution of POPs and to evaluate the potential environmental risks they pose. The scope focuses on the secondary emissions of POPs from thawing permafrost and glaciers, particularly in vulnerable high-altitude ecosystems like the Qinghai-Xizang Plateau (QXP), and their subsequent migration into the environment. The findings aim to inform future research directions and environmental policies to address the growing risks associated with POPs under climate change. Materials and methods This review synthesizes various studies and findings on POPs stored in permafrost, glaciers, soil, and vegetation. The analysis draws upon data from multiple sources, including field studies, remote sensing, and climate models, to evaluate how climate warming influences the release and redistribution of POPs in different environmental matrices. The review focuses on how temperature rise, thawing of permafrost, glacier melting, and changes in land cover and water systems contribute to the mobilization of POPs. Seasonal variations in the release and migration of POPs are also discussed, with particular attention to how extreme weather events, such as storms and wildfires, may exacerbate this process. Results The results indicate that rising temperatures are reactivating POPs stored in permafrost and glaciers, with significant releases observed in regions such as the QXP. Melting ice and thawing ground release POPs including HCHs (hexachlorocyclohexanes), PCBs (polychlorinated biphenyls), and PAHs (polycyclic aromatic hydrocarbons) into the atmosphere and aquatic systems, with volatilization increasing during warmer periods. Extreme events such as wildfires further enhance the emission and dispersal of these pollutants. Discussion The discussion focuses on how climate change accelerates the release of POPs from their long-term storage in permafrost and glaciers. Warming temperatures enhance the volatility of these pollutants, making them more prone to release into the atmosphere, water bodies, and soils. The review identifies that, although the primary sources of POPs have been reduced through measures like the Stockholm Convention, the secondary release of POPs from thawing permafrost and glaciers has become an increasingly important source. The seasonal patterns of POPs release are also explored, with POP concentrations peaking during warmer months and in response to human activities like biomass burning. Additionally, extreme events, such as wildfires and glacier melt, are shown to significantly affect the migration of POPs, increasing their distribution and bioaccumulation in remote ecosystems. Conclusions The secondary emission of POPs from permafrost and glacier melt represents a significant environmental concern in the context of global climate change. Rising temperatures are enhancing the volatility of these pollutants, facilitating their release into the atmosphere, water bodies, and soil. This process, combined with seasonal changes and extreme events such as wildfires and glacier melt, exacerbates the migration and bioaccumulation of POPs in remote ecosystems, including those in the Arctic and the QXP. While efforts to reduce primary emissions, such as through the Stockholm Convention, have yielded positive results, the release of POPs from environmental reservoirs due to thawing permafrost and melting glaciers has emerged as a critical source of pollution that requires urgent attention. The impacts of these secondary emissions on ecosystems and human health are becoming increasingly apparent, underlining the need for immediate action. Recommendations and perspectives To address the growing challenge of POPs secondary emissions, future research should prioritize improving monitoring systems to track the release and movement of these pollutants. Enhanced monitoring networks should be established in vulnerable regions, such as the Arctic and QXP, where permafrost degradation and glacier melt are particularly pronounced. It is also essential to strengthen environmental regulations and policies aimed at mitigating the risks associated with POPs exposure, especially in remote and sensitive ecosystems. Comprehensive studies are needed to better understand the long-term impacts of these secondary emissions, including their bioaccumulation in food chains and their potential effects on human health. In the context of a warming climate, further interdisciplinary research, including studies on climate-driven factors, should be conducted to assess the full scope of POPs migration and to inform future climate and environmental management strategies. Addressing the complexities of secondary emissions in these regions will be critical to protecting both ecosystems and human health in the face of ongoing climate change.