Spatial Distribution of the Persistent Organic Pollutants across the Tibetan Plateau and Its Linkage with the Climate Systems: Five Year Air Monitoring Study

Abstract. The Tibetan Plateau (TP) has been contaminated by persistent organic pollutants (POPs), including legacy organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) through atmospheric transport. The exact source regions, transport pathways and time trends of POPs to the TP are not well understood. Here XAD-based passive air samplers (PAS) were deployed at 16 Tibetan background sites from 2007 to 2012 to gain further insight into spatial patterns and temporal trends of OCPs and PCBs. The southeastern TP was characterized by dichlorodiphenyltrichloroethane (DDT) -related chemicals delivered by Indian Monsoon air masses. The northern and northwestern TP displayed the greatest absolute concentration and relative abundance of hexachlorobenzene (HCB) in the atmosphere, caused by the westerly-driven European air masses. The interactions between the DDT polluted Indian monsoon air and the clean westerly winds formed a transition zone in central Tibet where both DDT and HCB were the dominant chemicals. Based on 5-year of continuous sampling, our data indicated declining concentrations of HCB and hexachlorocyclohexanes (HCHs) across the Tibetan region. Inter-annual trends of DDT class chemicals, however, showed less variation during this 5-year sampling period, which may be due to the on-going usage of DDT in India. This paper demonstrates the possibility of using POPs fingerprints to investigate the climate interactions and the validity of using PAS to derive inter-annual atmospheric POPs time trends.

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Spatial distribution of the persistent organic pollutants across the Tibetan Plateau and its linkage with the climate systems: a 5-year air monitoring study

Atmospheric Chemistry and Physics ◽

10.5194/acp-16-6901-2016 ◽

2016 ◽

Vol 16 (11) ◽

pp. 6901-6911 ◽

Cited By ~ 23

Author(s):

Xiaoping Wang ◽

Jiao Ren ◽

Ping Gong ◽

Chuanfei Wang ◽

Yonggang Xue ◽

...

Keyword(s):

Tibetan Plateau ◽

Organic Pollutants ◽

Persistent Organic Pollutants ◽

Time Trends ◽

Indian Monsoon ◽

Temporal Trends ◽

Sampling Period ◽

The Tibetan Plateau ◽

Transport Pathways ◽

Air Masses

Abstract. The Tibetan Plateau (TP) has been contaminated by persistent organic pollutants (POPs), including legacy organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) through atmospheric transport. The exact source regions, transport pathways and time trends of POPs to the TP are not well understood. Here polystyrene–divinylbenzene copolymer resin (XAD)-based passive air samplers (PASs) were deployed at 16 Tibetan background sites from 2007 to 2012 to gain further insight into spatial patterns and temporal trends of OCPs and PCBs. The southeastern TP was characterized by dichlorodiphenyltrichloroethane (DDT)-related chemicals delivered by Indian monsoon air masses. The northern and northwestern TP displayed the greatest absolute concentration and relative abundance of hexachlorobenzene (HCB) in the atmosphere, caused by the westerly-driven European air masses. The interactions between the DDT polluted Indian monsoon air and the clean westerly winds formed a transition zone in central Tibet, where both DDT and HCB were the dominant chemicals. Based on 5 years of continuous sampling, our data indicated declining concentrations of HCB and hexachlorocyclohexanes (HCHs) across the Tibetan region. Inter-annual trends of DDT class chemicals, however, showed less variation during this 5-year sampling period, which may be due to the ongoing usage of DDT in India. This paper demonstrates the possibility of using POP fingerprints to investigate the climate interactions and the validity of using PAS to derive inter-annual atmospheric POP time trends.

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Atmospheric processes of persistent organic pollutants over a remote lake of the central Tibetan Plateau: Implications for regional cycling

10.5194/acp-2016-989 ◽

2016 ◽

Author(s):

Jiao Ren ◽

Xiaoping Wang ◽

Chuanfei Wang ◽

Ping Gong ◽

Tandong Yao

Keyword(s):

Tibetan Plateau ◽

Organic Pollutants ◽

Persistent Organic Pollutants ◽

Secondary Source ◽

The Tibetan Plateau ◽

Lake Area ◽

Nam Co ◽

Surface Exchange ◽

Atmospheric Processes ◽

Water Gas

Abstract. Atmospheric processes (air-surface exchange, and atmospheric deposition and degradation) are crucial for understanding the global cycling and fate of persistent organic pollutants (POPs). However, such assessment over the Tibetan Plateau (TP) remains uncertain. More than 50 % of the Chinese lakes are located on the TP, which exerts a remarkable influence on the regional water, energy, and chemical cycling. In this study, air and water samples were simultaneously collected in Nam Co, a large lake on the TP, to test whether the lake is a "secondary source" or "sink" of POPs. Lower concentrations of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were observed in the atmosphere and lake water of Nam Co, while the levels of polycyclic aromatic hydrocarbons (PAHs) were relatively higher. Results of fugacity ratios and chiral signatures both suggest that the lake acted as the net sink of atmospheric hexachlorocyclohexanes (HCHs), following their long-range transport driven by the Indian Monsoon. Different behaviors were observed in the PAHs, which primarily originated from local biomass burning. Acenaphthylene, acenaphthene, and fluorene showed volatilization from the lake to the atmosphere; while other PAHs were deposited into the lake due to the integrated deposition process (wet/dry and air-water gas deposition) and limited atmospheric degradation. As the dominant PAH compound, phenanthrene exhibited a seasonal reversal of air-water gas exchange, which was likely related to the melting of the lake ice in May. The annual input of HCHs from air to the entire lake area (2015 km2) was estimated as 1.9 kg year−1, while those estimated for PAHs can potentially reach up to 550 kg year−1. This study highlights the significance of PAH deposition on the regional carbon cycling in the oligotrophic lakes of the TP.

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Persistent organic pollutants in the polar regions and the Tibetan Plateau: A review of current knowledge and future prospects

Environmental Pollution ◽

10.1016/j.envpol.2019.01.093 ◽

2019 ◽

Vol 248 ◽

pp. 191-208 ◽

Cited By ~ 14

Author(s):

Xiaoping Wang ◽

Chuanfei Wang ◽

Tingting Zhu ◽

Ping Gong ◽

Jianjie Fu ◽

...

Keyword(s):

Tibetan Plateau ◽

Organic Pollutants ◽

Persistent Organic Pollutants ◽

Current Knowledge ◽

The Tibetan Plateau ◽

Polar Regions ◽

Future Prospects

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Forest Fires Enhance the Emission and Transport of Persistent Organic Pollutants and Polycyclic Aromatic Hydrocarbons from the Central Himalaya to the Tibetan Plateau

Environmental Science & Technology Letters ◽

10.1021/acs.estlett.1c00221 ◽

2021 ◽

Author(s):

Ping Gong ◽

Xiaoping Wang

Keyword(s):

Polycyclic Aromatic Hydrocarbons ◽

Tibetan Plateau ◽

Organic Pollutants ◽

Persistent Organic Pollutants ◽

Aromatic Hydrocarbons ◽

Forest Fires ◽

The Tibetan Plateau ◽

Central Himalaya ◽

Polycyclic Aromatic

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A review of current knowledge and future prospects regarding persistent organic pollutants over the Tibetan Plateau

The Science of The Total Environment ◽

10.1016/j.scitotenv.2016.08.107 ◽

2016 ◽

Vol 573 ◽

pp. 139-154 ◽

Cited By ~ 39

Author(s):

Xiaoping Wang ◽

Ping Gong ◽

Chuanfei Wang ◽

Jiao Ren ◽

Tandong Yao

Keyword(s):

Tibetan Plateau ◽

Organic Pollutants ◽

Persistent Organic Pollutants ◽

Current Knowledge ◽

The Tibetan Plateau ◽

Future Prospects

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Biomagnification of persistent organic pollutants along a high-altitude aquatic food chain in the Tibetan Plateau: Processes and mechanisms

Environmental Pollution ◽

10.1016/j.envpol.2016.10.019 ◽

2017 ◽

Vol 220 ◽

pp. 636-643 ◽

Cited By ~ 25

Author(s):

Jiao Ren ◽

Xiaoping Wang ◽

Chuanfei Wang ◽

Ping Gong ◽

Xiruo Wang ◽

...

Keyword(s):

Tibetan Plateau ◽

High Altitude ◽

Organic Pollutants ◽

Persistent Organic Pollutants ◽

Food Chain ◽

The Tibetan Plateau ◽

Aquatic Food Chain ◽

Aquatic Food

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Environmental fate and behavior of persistent organic pollutants in Shergyla Mountain, southeast of the Tibetan Plateau of China

Environmental Pollution ◽

10.1016/j.envpol.2014.04.031 ◽

2014 ◽

Vol 191 ◽

pp. 166-174 ◽

Cited By ~ 27

Author(s):

Nali Zhu ◽

Karl-Werner Schramm ◽

Thanh Wang ◽

Bernhard Henkelmann ◽

Xiaoyan Zheng ◽

...

Keyword(s):

Tibetan Plateau ◽

Organic Pollutants ◽

Persistent Organic Pollutants ◽

Environmental Fate ◽

The Tibetan Plateau ◽

And Behavior ◽

Fate And Behavior

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Time trends of persistent organic pollutants (POPs) and Chemicals of Emerging Arctic Concern (CEAC) in Arctic air from 25 years of monitoring

The Science of The Total Environment ◽

10.1016/j.scitotenv.2021.145109 ◽

2021 ◽

Vol 775 ◽

pp. 145109

Author(s):

Fiona Wong ◽

Hayley Hung ◽

Helena Dryfhout-Clark ◽

Wenche Aas ◽

Pernilla Bohlin-Nizzetto ◽

...

Keyword(s):

Organic Pollutants ◽

Persistent Organic Pollutants ◽

Time Trends

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Atmospheric brown clouds reach the Tibetan Plateau by crossing the Himalayas

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-6007-2015 ◽

2015 ◽

Vol 15 (11) ◽

pp. 6007-6021 ◽

Cited By ~ 88

Author(s):

Z. L. Lüthi ◽

B. Škerlak ◽

S.-W. Kim ◽

A. Lauer ◽

A. Mues ◽

...

Keyword(s):

Tibetan Plateau ◽

Weather Prediction ◽

Mountain Range ◽

The Tibetan Plateau ◽

Pollution Transport ◽

Synoptic Scale ◽

Gangetic Plain ◽

Dark Light ◽

Air Masses ◽

Pollution Episode

Abstract. The Himalayas and the Tibetan Plateau region (HTP), despite being a remote and sparsely populated area, is regularly exposed to polluted air masses with significant amounts of aerosols including black carbon. These dark, light-absorbing particles are known to exert a great melting potential on mountain cryospheric reservoirs through albedo reduction and radiative forcing. This study combines ground-based and satellite remote sensing data to identify a severe aerosol pollution episode observed simultaneously in central Tibet and on the southern side of the Himalayas during 13–19 March 2009 (pre-monsoon). Trajectory calculations based on the high-resolution numerical weather prediction model COSMO are used to locate the source regions and study the mechanisms of pollution transport in the complex topography of the HTP. We detail how polluted air masses from an atmospheric brown cloud (ABC) over South Asia reach the Tibetan Plateau within a few days. Lifting and advection of polluted air masses over the great mountain range is enabled by a combination of synoptic-scale and local meteorological processes. During the days prior to the event, winds over the Indo-Gangetic Plain (IGP) are generally weak at lower levels, allowing for accumulation of pollutants and thus the formation of ABCs. The subsequent passing of synoptic-scale troughs leads to southwesterly flow in the middle troposphere over northern and central India, carrying the polluted air masses across the Himalayas. As the IGP is known to be a hotspot of ABCs, the cross-Himalayan transport of polluted air masses may have serious implications for the cryosphere in the HTP and impact climate on regional to global scales. Since the current study focuses on one particularly strong pollution episode, quantifying the frequency and magnitude of similar events in a climatological study is required to assess the total impact.

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