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Wang T, Xiang K, Zeng Y, Gu H, Guan Y, Chen S. Polycyclic aromatic hydrocarbons (PAHs) in air, foliage, and litter in a subtropical forest: Spatioseasonal variations, partitioning, and litter-PAH degradation. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 328:121587. [PMID: 37028783 DOI: 10.1016/j.envpol.2023.121587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 03/31/2023] [Accepted: 04/04/2023] [Indexed: 05/09/2023]
Abstract
Forest canopies play a vital role in scavenging airborne semi-volatile organic compounds. The present study measured polycyclic aromatic hydrocarbons (PAHs) in the understory air (at two heights), foliage, and litterfall in a subtropical rainforest (the Dinghushan mountain) in southern China. ∑17PAH concentrations in the air ranged from 2.75 to 44.0 ng/m3 (mean = 8.91 ng/m3), showing a spatial variation depending on the forest canopy coverage. Vertical distributions of the understory air concentrations also indicated PAH inputs from the above-canopy air. The concentrations of PAHs in fresh litter (with a mean of 261 ± 163 ng/g dry weight (dw)) were slightly lower than those in the foliage (362 ± 291 ng/g dw). Unlike the stable air PAH concentrations for most of the time of the year, the temporal variations of foliage and litter concentrations were remarkable but generally similar. Higher or comparable leaf/litter-air partition coefficients (KLA) in fresh litter compared with living KLA in leaves suggest that the forest litter layer is an efficient storage media for PAHs. Degradation of three-ring PAHs in litter under the field conditions follows first-order kinetics (R2 = 0.81), while the degradation is moderate for four-ring PAHs and insignificant for five- and six-ring PAHs. The yearly net cumulative deposition of PAHs through forest litterfall in the whole Dinghushan forest area over the sampling year was about 1.1 kg, 46% of the initial deposition (2.4 kg). This spatial variations study provides the results of in-field degradation of litter PAHs and makes a quantitative assessment of the litter deposition of PAHs, deducing their residence dynamics in the litter layer in a subtropical rainforest.
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Affiliation(s)
- Tao Wang
- School of Environment, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety, South China Normal University, Guangzhou, 510006, China; School of Marine Sciences, Nanjing University of Information Science and Technology, Nanjing, 210044, China
| | - Kai Xiang
- School of Environment, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety, South China Normal University, Guangzhou, 510006, China
| | - Yuan Zeng
- School of Environment, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety, South China Normal University, Guangzhou, 510006, China
| | - Haifeng Gu
- School of Marine Sciences, Nanjing University of Information Science and Technology, Nanjing, 210044, China; Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China
| | - Yufeng Guan
- School of Environment, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety, South China Normal University, Guangzhou, 510006, China
| | - Shejun Chen
- School of Environment, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety, South China Normal University, Guangzhou, 510006, China.
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Wu X, Sun W, Huai B, Wang L, Han C, Wang Y, Mi W. Seasonal variation and sources of atmospheric polycyclic aromatic hydrocarbons in a background site on the Tibetan Plateau. J Environ Sci (China) 2023; 125:524-532. [PMID: 36375935 DOI: 10.1016/j.jes.2022.02.042] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 02/21/2022] [Accepted: 02/23/2022] [Indexed: 06/16/2023]
Abstract
The study of atmospheric polycyclic aromatic hydrocarbons (PAHs) in northeastern Tibetan Plateau with fragile ecological environment and complex atmospheric circulation system is blank. To understand the characteristics and sources of persistent organic pollutants in the atmosphere of the northeastern Tibetan Plateau, we monitored levels in the central Qilian Mountain. From 2016 to 2017, we collected 45-pair (particle + gas) samples using active air samplers to investigate the sources, transport paths, and their influencing factors. Sources of PAHs were analysed with a source diagnostic model, and atmospheric transport paths were calculated. The concentration range for ∑15PAHs was 439-4666 pg/m3, and the average was 2015 pg/m3. The PAHs in central Qilian Mountain are mainly low molecular weight (LMW) PAHs. Winter concentrations of PAHs were higher than those in summer. The transport of PAHs is mainly affected by westerlies, and there are seasonal differences. Source analysis showed that PAHs mainly came from coal and biomass combustion and vehicle emissions, with seasonal differences. This study clarifies the concentration and seasonal variation of PAHs in the northern Tibetan Plateau, which is conducive to understanding the atmospheric transport process and fate of pollutants. The background site of Qilian Mountains located in the Silk Road economic belt has the value and significance of long-term observation of pollutants.
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Affiliation(s)
- Xuemei Wu
- College of Geography and Environment, Shandong Normal University, Jinan 250014, China
| | - Weijun Sun
- College of Geography and Environment, Shandong Normal University, Jinan 250014, China.
| | - Baojuan Huai
- College of Geography and Environment, Shandong Normal University, Jinan 250014, China
| | - Lei Wang
- College of Geography and Environment, Shandong Normal University, Jinan 250014, China
| | - Chuntan Han
- Qilian Alpine Ecology and Hydrology Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Yetang Wang
- College of Geography and Environment, Shandong Normal University, Jinan 250014, China
| | - Wenying Mi
- MINJIE Institute of Environmental Science and Health Research, Geesthacht 21502, Germany
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Wania F, Shunthirasingham C. Passive air sampling for semi-volatile organic chemicals. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2020; 22:1925-2002. [PMID: 32822447 DOI: 10.1039/d0em00194e] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
During passive air sampling, the amount of a chemical taken up in a sorbent from the air without the help of a pump is quantified and converted into an air concentration. In an equilibrium sampler, this conversion requires a thermodynamic parameter, the equilibrium sorption coefficient between gas-phase and sorbent. In a kinetic sampler, a time-averaged air concentration is obtained using a sampling rate, which is a kinetic parameter. Design requirements for kinetic and equilibrium sampling conflict with each other. The volatility of semi-volatile organic compounds (SVOCs) varies over five orders of magnitude, which implies that passive air samplers are inevitably kinetic samplers for less volatile SVOCs and equilibrium samplers for more volatile SVOCs. Therefore, most currently used passive sampler designs for SVOCs are a compromise that requires the consideration of both a thermodynamic and a kinetic parameter. Their quantitative interpretation depends on assumptions that are rarely fulfilled, and on input parameters, that are often only known with high uncertainty. Kinetic passive air sampling for SVOCs is also challenging because their typically very low atmospheric concentrations necessitate relatively high sampling rates that can only be achieved without the use of diffusive barriers. This in turn renders sampling rates dependent on wind conditions and therefore highly variable. Despite the overall high uncertainty arising from these challenges, passive air samplers for SVOCs have valuable roles to play in recording (i) spatial concentration variability at scales ranging from a few centimeters to tens of thousands of kilometers, (ii) long-term trends, (iii) air contamination in remote and inaccessible locations and (iv) indoor inhalation exposure. Going forward, thermal desorption of sorbents may lower the detection limits for some SVOCs to an extent that the use of diffusive barriers in the kinetic sampling of SVOCs becomes feasible, which is a prerequisite to decreasing the uncertainty of sampling rates. If the thermally stable sorbent additionally has a high sorptive capacity, it may be possible to design true kinetic samplers for most SVOCs. In the meantime, the passive air sampling community would benefit from being more transparent by rigorously quantifying and explicitly reporting uncertainty.
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Affiliation(s)
- Frank Wania
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario M1C 1A4, Canada.
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Dotel J, Gong P, Wang X, Pokhrel B, Wang C, Nawab J. Determination of dry deposition velocity of polycyclic aromatic hydrocarbons under the sub-tropical climate and its implication for regional cycling. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 261:114143. [PMID: 32066057 DOI: 10.1016/j.envpol.2020.114143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 09/10/2019] [Accepted: 02/05/2020] [Indexed: 06/10/2023]
Abstract
Atmospheric dry deposition is a major pathway for removal of polycyclic aromatic hydrocarbons (PAHs) from the atmosphere. Despite its significance in the atmospheric environment, measurements of the dry deposition velocity (VDD) and deposition fluxes (FDD) of PAHs are relatively limited. In this study, a passive dry deposition (PAS-DD) collector was co-deployed with passive air sampler polyurethane foam (PAS-PUF) from November 2015 to November 2016 in two major cities (Kathmandu and Pokhara), Nepal, to investigate the VDD and FDD of PAHs. The VDD of PAHs ranged from 0.25 to 0.5 cm s-1 and the annual average was recorded as 0.37 ± 0.08 cm s-1. On the basis of measured VDD, the FDD of ∑15PAHs in Kathmandu and Pokhara were estimated as 66 and 5 kg yr-1 respectively. According to the measured VDD of Kathmandu and Pokhara in this study, and the previously published VDD data of Toronto, Canada, where the same PAS-DD collector was used, a significant multi-linear correlation (r2 = 0.79, p < 0.05) was found between VDD of higher molecular weight (HMW with MW ≥ 228.3 and ≥ 4 rings) PAHs and meteorological parameters (precipitation and wind speed) and vapor pressure of PAHs. To the best of our knowledge, this enabled the development of an empirical model that can exhibit the combined effects of meteorological conditions on the VDD of HMW PAHs. The model was used to estimate the VDD values for major cities in the Indo-Gangetic Plain (IGP) region and the maximum estimated proportion of HMW PAHs deposited by dry deposition reached up to 60% of total emissions. Although PAH emissions in the IGP region pose global risks, the results of this study highlight the considerable risk for local IGP residents, due to the large dry deposition proportion of HMW PAHs.
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Affiliation(s)
- Jagdish Dotel
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ping Gong
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China; Chinese Academy of Sciences Center for Excellence in Tibetan Plateau Earth Sciences, Beijing, 100101, China
| | - Xiaoping Wang
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China; Chinese Academy of Sciences Center for Excellence in Tibetan Plateau Earth Sciences, Beijing, 100101, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Balram Pokhrel
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China; Department of Environmental Science, Kathmandu University, Dhulikhel, Nepal
| | - Chuanfei Wang
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China; Chinese Academy of Sciences Center for Excellence in Tibetan Plateau Earth Sciences, Beijing, 100101, China
| | - Javed Nawab
- Department of Environmental Sciences Abdul Wali Khan University Mardan, 23200, Pakistan
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Gong P, Wang X, Pokhrel B, Wang H, Liu X, Liu X, Wania F. Trans-Himalayan Transport of Organochlorine Compounds: Three-Year Observations and Model-Based Flux Estimation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:6773-6783. [PMID: 31122015 DOI: 10.1021/acs.est.9b01223] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
High mountains can trap semivolatile chemicals, such as persistent organic pollutants (POPs), and hinder their dispersion. However, both deep convection and mountain valleys can facilitate POPs' transport over mountains, which have not been investigated before. In this study, a three-year sampling campaign along a south-north altitudinal transect (100-5200m) across the central Himalayas, coupled with a multicompartment contaminant fate model, was conducted for describing the transport processes of POPs. The results show that POPs emitted in the lowlands of the Himalayas can be transported to high altitudes and further to the inner part of the Tibetan Plateau. Modeling suggests that more than 90% of POPs are trapped along the way due to gaseous deposition to soil/foliage and rainfall scavenging; while 2 × 10-3 to 1 × 10-1 Giga-grams/year of POPs are transported across the Himalayas. The transport flux along valleys is 2-3 times higher than that across the mountain ridge. However, due to the limited spatial coverage of mountain valleys, the amount of POPs transported through valleys only accounts for a small part of the total transport. This study shows that POPs can overcome the blocking effect of the Himalayas, and high altitude transport across the mountain ridge is the dominant transport pathway.
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Affiliation(s)
- Ping Gong
- Key Laboratory of Tibetan Environmental Changes and Land Surface Process , Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS) , Beijing 100101 , China
- CAS Center for Excellence in Tibetan Plateau Earth Sciences , Beijing 100101 , China
| | - Xiaoping Wang
- Key Laboratory of Tibetan Environmental Changes and Land Surface Process , Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS) , Beijing 100101 , China
- CAS Center for Excellence in Tibetan Plateau Earth Sciences , Beijing 100101 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Balram Pokhrel
- Key Laboratory of Tibetan Environmental Changes and Land Surface Process , Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS) , Beijing 100101 , China
- School of Science , Kathmandu University , Dhulikhel 45200 , Nepal
| | - Hailong Wang
- Atmospheric Sciences and Global Change Division , Pacific Northwest National Laboratory (PNNL) , Richland , Washington 99352 , United States
| | - Xiande Liu
- Chinese Research Academy of Environmental Sciences , Beijing 100012 , China
| | - Xiaobo Liu
- Key Laboratory of Tibetan Environmental Changes and Land Surface Process , Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS) , Beijing 100101 , China
- Kathmandu Center for Research and Education, CAS-TU , Kathmandu 44618 , Nepal
| | - Frank Wania
- Department of Physical and Environmental Sciences , University of Toronto Scarborough , 1265 Military Trail , Toronto , ON M1C 1A4 , Canada
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Wang Z, Liu S, Zhang T. Characteristics of polycyclic aromatic hydrocarbons (PAHs) in soil horizon from high-altitude mountains in Northeastern China. CHEMOSPHERE 2019; 225:93-103. [PMID: 30861387 DOI: 10.1016/j.chemosphere.2019.03.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 02/11/2019] [Accepted: 03/01/2019] [Indexed: 05/21/2023]
Abstract
Previous studies have reported that soils from high altitude mountains act as primary reservoirs of polycyclic aromatic hydrocarbons (PAHs). This study aims to investigate the spatial distribution and illuminate the behaviors of PAHs in soil profiles from Mt. Wangtiane in Northeastern China. Soil samples were collected by different soil genetic horizon rather than by depths at 10 sites, with altitudes from 1000 m to 2022 m. Results showed significantly (p < 0.05) higher concentrations of total PAHs (16 PAHs) in O-horizons (371 ± 32 to 2224 ± 207 ng g-1) than those in A- and B-horizons (362 ± 30 to 666 ± 58 ng-1 and 289 ± 23 to 571 ± 50 ng g-1, respectively). An increasing trend of PAH concentrations with altitude was observed from elevation ca. 1000 m to ca. 1800 m, but no correlation between PAH concentrations and altitude along transect was found. Total organic carbon (TOC) was strongly correlated (p < 0.05) with PAH concentrations in O-horizons but showed no relation with those in A- and B-horizons. Low molecular weight (LMW) PAHs were dominated in each soil horizon, and decreased percentage of high molecular weight (HMW) PAHs with depths in soils profiles was observed. Principle component analysis (PCA) separated O-horizons and A-/B-horizons based on PAH compositions, again suggesting different PAH compositions among soil horizons. These results reflect various processes of PAHs, including deposition, vertical motion, degradation and photolysis. This study suggests it is better to investigate characteristics of PAHs in soils by horizon rather than by depths.
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Affiliation(s)
- Zucheng Wang
- Institute for Peat & Mire Research, Key Laboratory of Geographical Processes and Ecological Security in Changbai Mountains, Ministry of Education, Northeast Normal University, Changchun, Jilin, China; Jilin Provincial Key Laboratory for Wetland Ecological Processes and Environmental Change in the Changbai Mountains, China.
| | - Shasha Liu
- Institute for Peat & Mire Research, Key Laboratory of Geographical Processes and Ecological Security in Changbai Mountains, Ministry of Education, Northeast Normal University, Changchun, Jilin, China; Jilin Provincial Key Laboratory for Wetland Ecological Processes and Environmental Change in the Changbai Mountains, China
| | - Tianyu Zhang
- Institute for Peat & Mire Research, Key Laboratory of Geographical Processes and Ecological Security in Changbai Mountains, Ministry of Education, Northeast Normal University, Changchun, Jilin, China; Jilin Provincial Key Laboratory for Wetland Ecological Processes and Environmental Change in the Changbai Mountains, China
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Kalina J, Scheringer M, Borůvková J, Kukučka P, Přibylová P, Sáňka O, Melymuk L, Váňa M, Klánová J. Characterizing Spatial Diversity of Passive Sampling Sites for Measuring Levels and Trends of Semivolatile Organic Chemicals. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:10599-10608. [PMID: 30107733 DOI: 10.1021/acs.est.8b03414] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Passive air sampling of semivolatile organic compounds (SVOCs) is a relatively inexpensive method that facilitates extensive campaigns with numerous sampling sites. An important question in the design of passive-sampling networks concerns the number and location of samplers. We investigate this question with the example of 17 SVOCs sampled at 14 background sites across the Czech Republic. More than 200 time series (length 5-11 years) were used to characterize SVOC levels and trends in air between 2003 and 2015. Six polychlorinated biphenyls (PCBs), 6 polyaromatic hydrocarbons (PAHs), and 5 organochlorine pesticides (OCPs) at 14 sites were assessed using data from the MONET passive sampling network. Significant decreases were found for most PCBs and OCPs whereas hexachlorobenzene (HCB) and most PAHs showed (mostly insignificant) increases. Spatial variability was rather low for PCBs and OCPs except for dichlorodiphenyltrichloroethane (DDT) and rather high for PAHs. The variability of the SVOC levels and trends depends on characteristics of the sites including their remoteness, landscape, population, and pollution sources. The sites can be grouped in distinct clusters, which helps to identify similar and, thereby, potentially redundant sites. This information is useful when monitoring networks need to be optimized regarding the location and number of sites.
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Affiliation(s)
- Jiří Kalina
- Research Centre for Toxic Compounds in the Environment, RECETOX , Kamenice 5 , 625 00 Brno , Czech Republic
| | - Martin Scheringer
- Research Centre for Toxic Compounds in the Environment, RECETOX , Kamenice 5 , 625 00 Brno , Czech Republic
- Institute of Biogeochemistry and Pollutant Dynamics , ETH Zürich , 8092 Zürich , Switzerland
| | - Jana Borůvková
- Research Centre for Toxic Compounds in the Environment, RECETOX , Kamenice 5 , 625 00 Brno , Czech Republic
| | - Petr Kukučka
- Research Centre for Toxic Compounds in the Environment, RECETOX , Kamenice 5 , 625 00 Brno , Czech Republic
| | - Petra Přibylová
- Research Centre for Toxic Compounds in the Environment, RECETOX , Kamenice 5 , 625 00 Brno , Czech Republic
| | - Ondřej Sáňka
- Research Centre for Toxic Compounds in the Environment, RECETOX , Kamenice 5 , 625 00 Brno , Czech Republic
| | - Lisa Melymuk
- Research Centre for Toxic Compounds in the Environment, RECETOX , Kamenice 5 , 625 00 Brno , Czech Republic
| | - Milan Váňa
- Czech Hydrometeorological Institute - Košetice Observatory , 394 22 Košetice , Czech Republic
| | - Jana Klánová
- Research Centre for Toxic Compounds in the Environment, RECETOX , Kamenice 5 , 625 00 Brno , Czech Republic
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Guo J, Kang S, Huang J, Zhang Q, Rupakheti M, Sun S, Tripathee L, Rupakheti D, Panday AK, Sillanpää M, Paudyal R. Characterizations of atmospheric particulate-bound mercury in the Kathmandu Valley of Nepal, South Asia. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 579:1240-1248. [PMID: 27913014 DOI: 10.1016/j.scitotenv.2016.11.110] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 11/14/2016] [Accepted: 11/16/2016] [Indexed: 06/06/2023]
Abstract
The Kathmandu Valley, located in the Himalayan foothills in Nepal, is heavily polluted. In order to investigate ambient particulate-bound mercury (Hg) in the Kathmandu Valley, a total 64 total suspended particulates (TSP) samples were collected from a sub-urban site in the Kathmandu Valley, the capital region of Nepal during a sampling period of an entire year (April 2013-April 2014). They were analyzed for ambient particulate-bound Hg (PBM) using thermal desorption combined with cold vapor atomic spectroscopy. In our knowledge, it is the first study of ambient PMB in the Kathmandu Valley and the surrounding broader Himalayan foothill region. The average concentration of PBM over the entire sampling period of a year was found to be 850.5 (±962.8) pg m-3 in the Kathmandu Valley. This is comparable to those values reported in the polluted cities of China and significantly higher than those observed in most of urban areas in Asia and other regions of world. The daily average Hg contents in TSP (PBM/TSP) ranges from 269.7 to 7613.0ngg-1 with an average of 2586.0 (±2072.1) ng g-1, indicating the high enrichment of Hg in TSP. The average concentrations of PBM were higher in the winter and pre-monsoon season than in the monsoon and post-monsoon season. The temporal variations in the strength of anthropogenic emission sources combined with other influencing factors, such as ambient temperature and the removal of atmospheric aerosols by wet scavenging are attributable to the seasonal variations of PBM. The considerably high dry deposition flux of PBM estimated by using a theoretical model was 135μgm-2yr-1 at the Kathmandu Valley. This calls for an immediate attention to addressing ambient particulate Hg in the Kathmandu Valley, including considering it as a key component of future air quality monitoring activities and mitigation measures.
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Affiliation(s)
- Junming Guo
- Key Laboratory of Tibetan Environment Changs and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12, 50130 Mikkeli, Finland; Graduate University of Chinese Academy of Sciences, Beijing 100039, China
| | - Shichang Kang
- State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Jie Huang
- Key Laboratory of Tibetan Environment Changs and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Qianggong Zhang
- Key Laboratory of Tibetan Environment Changs and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | | | - Shiwei Sun
- State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; Graduate University of Chinese Academy of Sciences, Beijing 100039, China
| | - Lekhendra Tripathee
- Key Laboratory of Tibetan Environment Changs and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12, 50130 Mikkeli, Finland
| | - Dipesh Rupakheti
- Key Laboratory of Tibetan Environment Changs and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; Graduate University of Chinese Academy of Sciences, Beijing 100039, China
| | - Arnico K Panday
- International Centre for Integrated Mountain Development, Kathmandu, Nepal
| | - Mika Sillanpää
- Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12, 50130 Mikkeli, Finland
| | - Rukumesh Paudyal
- State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; Graduate University of Chinese Academy of Sciences, Beijing 100039, China
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