Himalayan Environment Research Institute HERI

Kathmandu, Nepal

Himalayan Environment Research Institute HERI

Kathmandu, Nepal

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Li X.,Chinese Academy of Sciences | Li X.,University of Chinese Academy of Sciences | Kang S.,Chinese Academy of Sciences | Kang S.,University of Chinese Academy of Sciences | And 15 more authors.
Science of the Total Environment | Year: 2017

Light-absorbing impurities (LAIs), such as organic carbon (OC), black carbon (BC), and mineral dust (MD) deposited on the glacier surface can reduce albedo, thus accelerating the glacier melt. Surface fresh snow, aged snow, granular ice, and snowpits samples were collected between August 2014 and October 2015 on the Xiao Dongkemadi (XDKMD) glacier (33°04'N, 92°04'E) in the central Tibetan Plateau (TP). The spatiotemporal variations of LAIs concentrations in the surface snow/ice were observed to be consistent, differing mainly in magnitudes. LAIs concentrations were found to be in the order: granular ice > snowpit > aged snow > fresh snow, which must be because of post-depositional effects and enrichment. In addition, more intense melting led to higher LAIs concentrations exposed to the surface at a lower elevation, suggesting a strong negative relationship between LAIs concentrations and elevation. The scavenging efficiencies of OC and BC were same (0.07 ± 0.02 for OC, 0.07 ± 0.01 for BC), and the highest enrichments was observed in late September and August for surface snow and granular ice, respectively. Meanwhile, as revealed by the changes in the OC/BC ratios, intense glacier melt mainly occurred between August and October. Based on the SNow ICe Aerosol Radiative (SNICAR) model simulations, BC and MD in the surface snow/ice were responsible for about 52% ± 19% and 25% ± 14% of the albedo reduction, while the radiative forcing (RF) were estimated to be 42.74 ± 40.96 W m− 2 and 21.23 ± 22.08 W m− 2, respectively. Meanwhile, the highest RF was observed in the granular ice, suggesting that the exposed glaciers melt and retreat more easily than the snow distributed glaciers. Furthermore, our results suggest that BC was the main forcing factor compared with MD in accelerating glacier melt during the melt season in the Central TP. © 2017 Elsevier B.V.

Tripathee L.,Chinese Academy of Sciences | Tripathee L.,Lappeenranta University of Technology | Tripathee L.,Himalayan Environment Research Institute HERI | Kang S.,Chinese Academy of Sciences | And 5 more authors.
Atmosphere | Year: 2016

The total suspended particulate (TSP) samples were collected from April 2013 to April 2014 at the urban location of Pokhara valley in western Nepal. The major aims were to study, quantify, and understand the concentrations and variations of TSP and major water-soluble inorganic ions (WSIIs) in the valley with limited data. The annual average TSP mass concentration was 135.50 ± 62.91 μg/m3. The average analyzed total WSIIs accounted for 14.4% of total TSP mass. Major anions and cations in TSP samples were SO4 2- and Ca2+, respectively. Seasonal differences in atmospheric conditions explain the clear seasonal variations of ions, with higher concentrations during pre-monsoon and winter and lower concentrations during the monsoon period. Neutralization factor calculations suggested that Ca2+ in the Pokhara valley mostly neutralizes the acidity in the atmosphere. Principle component analysis, NO3 -/SO4 2- ratio, and non-sea salt fraction calculations suggested that the WSIIs in the valley were mostly derived from anthropogenic activities and crustal mineral dust, which was also supported by the results from precipitation chemistry over the central Himalayas, Nepal. In addition, back trajectories analysis has suggested that the air pollution transported from and through Indo-Gangetic Plains (IGP) during the dry periods, which has resulted in high ionic loadings during this period. Average NO3 -/SO4 2- ratio was found to be 0.69, indicating the dominance of stationary sources of TSP in Pokhara valley. Secondary inorganic aerosols can have an adverse health impact on the human population in the valley. The data set from this one-year study provides new insights into the composition of WSIIs in the foothills of the Himalayas, which can be of great importance for understanding the atmospheric environment in the region.

Sun S.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Sun S.,University of Chinese Academy of Sciences | Kang S.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Kang S.,Chinese Academy of Sciences | And 12 more authors.
Journal of Environmental Sciences (China) | Year: 2016

The Tibetan Plateau is home to the largest aggregate of glaciers outside the Polar Regions and is a source of fresh water to 1.4 billion people. Yet little is known about the transportation and cycling of Hg in high-elevation glacier basins on Tibetan Plateau. In this study, surface snow, glacier melting stream water and lake water samples were collected from the Qiangyong Glacier Basin. The spatiotemporal distribution and transportation of Hg from glacier to lake were investigated. Significant diurnal variations of dissolved Hg (DHg) concentrations were observed in the river water, with low concentrations in the morning (8:00. am-14:00. pm) and high concentrations in the afternoon (16:00. pm-20:00. pm). The DHg concentrations were exponentially correlated with runoff, which indicated that runoff was the dominant factor affecting DHg concentrations in the river water. Moreover, significant decreases of Hg were observed during transportation from glacier to lake. DHg adsorption onto particulates followed by the sedimentation of particulate-bound Hg (PHg) could be possible as an important Hg removal mechanism during the transportation process. Significant decreases in Hg concentrations were observed downstream of Xiao Qiangyong Lake, which indicated that the high-elevation lake system could significantly affect the distribution and transportation of Hg in the Qiangyong Glacier Basin. © 2016.

Tripathee L.,Chinese Academy of Sciences | Tripathee L.,Himalayan Environment Research Institute HERI | Tripathee L.,Lappeenranta University of Technology | Kang S.,Chinese Academy of Sciences | And 13 more authors.
Environmental Earth Sciences | Year: 2016

Soils in the fragile Himalayan region could be affected by the transport and deposition of potentially toxic trace metals (PTEs) from urban and industrialized areas of South Asia. The transported pollutants could pose a serious threat to the soil quality in the pristine regions at high elevations having minimal direct human influence. Therefore, it is important to understand the geochemical and physical characteristics of soils in this region and determine the extent of their chemical pollution. In order to achieve these objectives, soil samples were collected from different elevation transects of the Langtang Himalaya in Nepal. The samples were analyzed for PTEs and rare earth elements for the purpose of identifying their possible sources and to evaluate their environmental risk in the region. The PTEs and REEs concentrations were measured by ICP-MS (X-7; Thermo-elemental, USA) and total organic carbon (TOC) by TOC analyzer. The results of this study were comparable to those of the world average background soil as well as the Tibetan plateau surface soil. TOC revealed a decreasing trend with increasing elevation. Correlation analysis and principle component analysis (PCA) indicated that most of the elements were highly associated with major crustal elements, suggesting that their primary sources were of natural origin. Furthermore, the geo-accumulation index (Igeo), enrichment factor (EF) and pollution index (PI) analyses indicated that the Himalayan soils represent minimal pollution and the data from this study may be used as background values for the Himalayan region in the future studies. REEs in the soil samples were found to be consistent with an order of average abundance of the Earth’s crust. In addition, the chondrite-normalized REE distribution of the light REE suggested enrichment of LREE and Eu depletion. Moreover, this study emphasized that soils of the Himalayan region could, in future, be under threat of elemental pollution from long-range transport via atmospheric circulation and deposition. © 2016, Springer-Verlag Berlin Heidelberg.

Sharma C.M.,Kathmandu University | Sharma C.M.,CAS Institute of Tibetan Plateau Research | Sharma C.M.,Lappeenranta University of Technology | Kang S.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | And 11 more authors.
Water, Air, and Soil Pollution | Year: 2015

Two lakes, one from the remote high altitude on the southern slope of the Himalaya (Lake Gosainkunda) and another from the urban mid-hill area (Lake Phewa) were studied for evaluating anthropogenic inputs of the pollutants, particularly mercury (Hg) and other trace elements (TEs) (such as Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb). A total of 77 water samples, 24 from Lake Gosainkunda and 53 from Lake Phewa were collected from different depth profiles during October/November 2010. Concentrations of Hg were significantly higher in Lake Gosainkunda compared to Lake Phewa probably due to long-range transport of Hg and its deposition on high altitudes of the Himalayas, in addition to the probable natural geological sources. Some of the TEs (such as Al, V, Cr, Mn, Fe, and Co) show crustal origin in Lake Gosainkunda, whereas others such as Ni, Cu, Zn, Cd, and Pb indicate possible anthropogenic origin (enrichment factor (EF)∈>∈4). On the other hand, Al, V, Cr, Ni, and Cu show crustal origin in Lake Phewa and the remaining TEs (Mn, Fe, Co, Zn, Cd, and Pb) showed high EF values relative to the crustal elements suggesting potential anthropogenic inputs of the pollutants. The study further indicates that two studied lakes have different potential sources for Mn, Fe, Co, Ni, and Cu regarding TE pollution. A high enrichment of Cd and Pb in high-altitude lake (with less anthropogenic activities) compared to the low-altitude lake (with high anthropogenic activities) indicates atmospheric long-range transportation of the pollutants in remote areas of the Himalayas which might be possible as air masses pass through the industrial areas and deposit in the high altitudes. © 2015 Springer International Publishing Switzerland.

Paudyal R.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Paudyal R.,University of Chinese Academy of Sciences | Paudyal R.,Himalayan Environment Research Institute HERI | Paudyal R.,Lappeenranta University of Technology | And 11 more authors.
Environmental Earth Sciences | Year: 2016

During pre-monsoon of 2013, water samples were collected from 30 sites of two major rivers, viz. Dudh Koshi and Indrawati to assess the river water quality on the southern side of the Nepalese Himalayas. The physical parameters such as pH, EC, turbidity and water temperature were measured in the field and major ions (Na+, NH4 +, K+, Ca2+, Mg2+, Cl−, SO4 2−, and NO3 −) and element concentrations (Li, Sc, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, As, Rb, Sr, Cs, Ba, Pb, U, Y, Zr, Nb and Cd) in the water samples were analyzed in the laboratory. The result indicated river waters were neutral to mostly alkaline with pH ranging from 6.57 to 8.81 and EC ranging from 10.5 to 321 μS/cm. The lower values of turbidity were recorded in the pristine tributaries of Dudh Koshi, whereas the main rivers had the higher values with a range of 0.51–515 NTU. Bicarbonate (HCO3 −) showed a significant correlation with Ca2+ and Mg2+, suggesting carbonate weathering as the dominant geochemical process in the region. Furthermore, the Gibbs plot also suggested the dominance of rock weathering. Very low concentration of trace elements was found in most of the samples which were within the WHO guidelines. In addition, the concentrations of toxic elements such as As and Pb were below the detectable limits in most of the samples. Furthermore, the analysis of PCA suggests that most of the elements originated from natural weathering; however, there were some evidences of anthropogenic effect on water quality which may not be critical issue at present but can be of concern in future. © 2015, Springer-Verlag Berlin Heidelberg.

Tripathee L.,Chinese Academy of Sciences | Tripathee L.,Lappeenranta University of Technology | Tripathee L.,Himalayan Environment Research Institute HERI | Kang S.,Chinese Academy of Sciences | And 9 more authors.
Bulletin of Environmental Contamination and Toxicology | Year: 2016

This study investigates the contamination levels and risk assessments of 14 elements (Ba, Cd, Co, Cr, Cu, Pb, Li, Mn, Mo, Ni, Sb, Sr, V and Zn) in three sub-basins of Himalayan rivers. Water samples were collected and the hazard quotient (HQ), hazard index (HI), and water quality index (WQI) were calculated. Total average concentrations of the metals were 135.03, 80.10 and 98.34 µg/L in Gandaki, Indrawati and Dudh Koshi rivers, respectively. The results of HQ and HI were less than unity, suggesting a low risk of metals in the region. However, HQ for antimony (Sb) was found to be 4.4 × 10−1, 2.1 × 10−1 and 5.4 × 10−1 in three river basins and HI near unity, suggesting its potential risk. Additionally, HI for Cd in Indrawati was 5.4 × 10−1 also close to unity, suggesting that Cd could have a potential risk to the local residents and aquatic ecosystems. Further, WQI suggested that the rivers Gandaki and Indrawati fell into the excellent water quality and river Dudh Koshi fell into good water quality. © 2016 Springer Science+Business Media New York

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