Tibetan Plateau (TP) is known as the water tower of Asia, and glaciers are solid reservoirs that can regulate the amount of water. Black carbon (BC), as one of the important factors accelerating glacier melting, is causing evident environmental effects in snow and ice. However, a systematical summary of the potential sources, analytical methods, distributions, and environmental effects of BC in snow and ice on the TP's glaciers is scarce. Therefore, this study drew upon existing research on snow and ice BC on glaciers of the TP to describe the detection methods and uncertainties associated with them to clarify the concentrations of BC in snow and ice and their climatic effects. The primary detection methods are the optical method, the thermal-optical method, the thermochemical method, and the single-particle soot photometer method. However, few studies have systematically compared the results of BC and this study found that concentrations of BC in different types of snow and ice varied by 1-3 orders of magnitude, which drastically affected the regional hydrologic process by potentially accelerating the ablation of glaciers by approximately 15% and reducing the duration of snow accumulation by 3-4 days. In general, results obtained from the various testing methods differ drastically, which limited the systematical discussion. Accordingly, a universal standard for the sampling and measurement should be considered in the future work, which will be beneficial to facilitate the comparison of the spatiotemporal features and to provide scientific data for the model-simulated climatic effects of BC.

Perfluoroalkyl acid analogs (PFAAs) are a class of chemically stable environmentally persistent organic pollutants (POPs) that are difficult to degrade and have a strong capacity to accumulate in the human body. PFAAs have been found to be biotoxic to humans and have been detected in various environmental media, especially in the cryosphere at trace concentrations. The cryosphere, sensitively responds to climate change, plays a crucial role in the global water, carbon and energy cycles. However, researches on cryosphere PFAAs especially in Tibetan Plateau (TP) is limited. Therefore, we summarize the physicochemical properties, physiological toxicity, spatiotemporal distribution, sources, diffusion and migration pathways, as well as analysis and removal methods of PFAAs in the cryosphere regions. The results show that PFAAs pollutants are mainly produced and distributed in the more economically developed countries in Europe and the United States, as well as in East Asia, and PFAAs can be transported by atmospheric circulation and water cycle to remote regions including cryosphere regions. The current detection methods for PFAAs in cryosphere need to be further refined for increased accuracy and convenience. There is also a need to develop more effective removal methods that will reduce the environmental and human threats posed by these PFAAs. Finally, we propose key scientific questions for future research in cryosphere including PFAAs redistribution influenced by cryosphere changes, human activities, and the interaction of other spheres.

Microplastic is an emerging contaminant of concern in soil globally due to its widespread and potential risks on the ecological system. Some basic issues such as the occurrence, source, and potential risks of microplastics in the soil are still open questions. These problems arise due to the lack of systematic and comprehensive analysis of microplastic in soils. Therefore, we comprehensively reviewed the current status of knowledge on microplastics in soil on detection, occurrence, characterization, source, and potential risk. Our review suggests that microplastics are ubiquitous in soil matrices globally. However, the research progress of microplastics in the soil is restricted by inherent technological inconsistencies and difficulties in analyzing particles in complex matrices, and studies on the occurrence and distribution of microplastics in soil environments remain very scarce, especially in Africa, South America, and Oceania. The consistency of the characteristics and composition of the microplastics in the aquatic environment and soil demonstrate they may share sources and exchange microplastics. Wide and varied sources of microplastic are constantly filling the soil, which causes the accumulation of microplastics in the soil. Studies on the effects and potential risks of microplastics in soil ecosystems are also reviewed. Limited research has shown that the combination and interaction of microplastics with contaminants they absorbed may affect soil health and function, and even migration along the food chain. The occurrence and impact of microplastic on the soil depend on the morphology, chemical components, and natural factors. We conclude that large research gaps exist in the quantification and estimation of regional emissions of microplastics in soil, factors affecting the concentration of microplastics, and microplastic disguising as soil carbon storage, which need more effort. (c) 2021 Elsevier B.V. All rights reserved.