RESUMO
Although river water is vital for drinking, irrigation and domestic needs, it faces threats from natural processes and human activities. Small and medium-sized rivers, especially in Nepal, remain understudied despite their vital importance in providing water to densely populated areas. This study evaluated the suitability for drinking and irrigation and the hydro-chemical characteristics of the Biring and Tangting rivers in Koshi province, Nepal. The results showed that turbidity, pH, EC, TDS, TH, NH4+, K+, Ca2+, Mg2+, Na+, Cl-, SO42-, HCO3- and NO3- values of all sampling sites in the Biring and Tangting rivers, except for the turbidity value of 10.39 NTU recorded in the PT9 site of the Tangting River, did not exceed maximum limit values set for drinking water. However, according to Water Quality Index results, the water of both rivers was in poor condition for drinking due to domestic wastewater discharges and cremation activities which caused high NH4+ levels. The major cations in both rivers were listed as Ca2⺠> Na⺠> K⺠> Mg2âº, while the major anions were listed as HCO3â» > Clâ» > SO42â» > NO3â». Gibbs and Piper diagrams showed that geogenic weathering of carbonate rocks prevailing in the region affected the hydrochemistry in both rivers. Evaluation based on seven different irrigation indices and US salinity laboratory diagram revealed that the water of both rivers was suitable for irrigation despite some magnesium-related limitations.
RESUMO
COVID-19 pandemic has caused profound impacts on human life and the environment including freshwater ecosystems globally. Despite the various impacts, the pandemic has improved the quality of the environment and thereby creating an opportunity to restore the degraded ecosystems. This study presents the imprints of COVID-19 lockdown on the surface water quality and chemical characteristics of the urban-based Bagmati River Basin (BRB), Nepal. A total of 50 water samples were collected from 25 sites of BRB during the monsoon season, in 2019 and 2020. The water temperature, pH, electrical conductivity, total dissolved solids, dissolved oxygen (DO), and turbidity were measured in-situ, while the major ions, total hardness, biological oxygen demand (BOD), and chemical oxygen demand (COD) were analyzed in the laboratory. The results revealed neutral to mildly alkaline waters with relatively moderate mineralization and dissolved chemical constituents in the BRB. The average ionic abundance followed the order of Ca2+ > Na+ > Mg2+ > K+ > NH4+ for cations and HCO3-> Cl- > SO42- > NO3- > PO43- for anions. Comparing to the pre-lockdown, the level of DO was increased by 1.5 times, whereas the BOD and COD were decreased by 1.5 and 1.9 times, respectively during the post-lockdown indicating the improvement of the quality water which was also supported by the results of multivariate statistical analyses. This study confirms that the remarkable recovery of degraded aquatic ecosystems is possible with limiting anthropic activities.
Assuntos
COVID-19 , Poluentes Químicos da Água , Controle de Doenças Transmissíveis , Ecossistema , Monitoramento Ambiental , Humanos , Nepal , Pandemias , Rios , SARS-CoV-2 , Poluentes Químicos da Água/análise , Qualidade da ÁguaRESUMO
The chemical characterization and assessment of the water quality in the headwater areas of the Himalaya are necessary for securing the water in the future. This study aims to assess the hydrochemistry and water quality concerning drinking and irrigational uses in the Seti River Basin (SRB), Nepal. A total of 45 water samples were collected in 2016 from the SRB during pre-monsoon, monsoon, and post-monsoon seasons, and pH, EC, TDS, and DO were measured on-site, whereas Ca2+, Mg2+, K+, Na+, Cl-, SO42-, NO3-, and dissolved Si were analyzed in the laboratory. The results revealed mildly alkaline pH (8.40 ± 0.43) with the pattern of average ionic dominancy: Ca2+ > Mg2+ > Na+ > K+ and HCO3- > SO42- > Cl- > NO3- for cations and anions, respectively. Gibbs diagram implied that the lithogenic weathering mainly controlled the solute acquisition process, which was further confirmed by the Piper diagram, exhibiting Ca-HCO3 as the governing hydrochemical facies (91%). The average molar ratios were 0.88, 8.33, and 6.86 of (Ca2+ + Mg2+)/TZ+, (Ca2+ + Mg2+)/(Na+ + K+), and HCO3-/(Na+ + K+), respectively, which specified that the carbonate weathering largely controlled the solute acquisition processes with a minor contribution of silicates. The mass budget calculation also confirmed the dominance of carbonate weathering (72.0%, 78.9%, and 62.0% in Pre-Monsoon, Monsoon, and Post-Monsoon, respectively) and the high monsoon rainfall's dilution effect to anthropogenic input of cations. Principal component analysis and correlation matrix exhibited that the major sources of ions in the basin were geogenic with minor anthropic signatures. Furthermore, water quality in connection to drinking and irrigation uses revealed that the basin has mostly retained its natural water quality. This investigation suggests that regular monitoring and assessment are essential for maintaining the water quality and ecological integrity in the Himalayan river basins.
Assuntos
Água Subterrânea , Poluentes Químicos da Água , Monitoramento Ambiental , Nepal , Rios , Poluentes Químicos da Água/análise , Qualidade da ÁguaRESUMO
To explore the seasonal variability and associated health risks of dissolved trace elements (TEs), a total of 45 water samples (15 samples in each season) were collected from the Seti River Basin during pre-monsoon, monsoon, and post-monsoon seasons. A total of 15 TEs were analysed and the results revealed that Arsenic (As), Chromium (Cr), and Nickel (Ni) were primarily controlled by lithogenic sources, whereas, Cadmium (Cd), Cobalt (Co), Cesium (Cs), Cupper (Cu), Manganese (Mn), Lead (Pb), and Zinc (Zn) were derived from both anthropic and geogenic sources. Additionally, the concentration of Zn was markedly high, especially during the post-monsoon season nearby the landfill site, indicating the anthropic signatures. The hazard index and cancer index were found to be < 1.00 and 10-6-10-4, respectively indicating minimum health impacts. The water quality index was < 50 throughout the sampling periods, with better water quality during the monsoon. This study could help to formulate the necessary policies for the sustainability of the Himalayan River Basins.
Assuntos
Metais Pesados , Oligoelementos , Poluentes Químicos da Água , Monitoramento Ambiental , Metais Pesados/análise , Nepal , Medição de Risco , Rios , Estações do Ano , Oligoelementos/análise , Poluentes Químicos da Água/análiseRESUMO
The elevated concentrations of arsenic in natural water are one of the major environmental threats to human health. However, the existing characteristics, controlling mechanisms, and associated risks of arsenic in natural waters in the Indus River Basin (IRB), Pakistan, are yet to be unequivocally understood. In this study, a total of 203 samples of surface water (SW), shallow groundwater (SGW), and deep groundwater (DGW) were collected from the IRB to assess the geochemical characteristics of arsenic and its associated health risks, as all three kinds of waters are the main sources of drinking and domestic usage. The results revealed that the arsenic concentrations in the SW, SGW, and DGW were in the ranges of 1.1-26.45, 1.05-44.44, and 0.67-41.09 µg L-1, respectively. Furthermore, the predominance of As (V) (97 %) over As(III) (3 %) confirmed that the desorption of As in oxidizing environments with elevated pH and Eh is the controlling mechanism. The hazard quotient of 11-45 % and 20-60 % samples and cancer risk of 26-64 % and 26-68 % samples indicated high health risks for the adults and children, respectively, suggesting an immense need for appropriate measures of reducing natural water arsenic concentrations in IRB from the human health perspectives.
Assuntos
Arsênio , Água Subterrânea , Poluentes Químicos da Água , Criança , Humanos , Arsênio/análise , Rios , Monitoramento Ambiental/métodos , Paquistão , Poluentes Químicos da Água/análise , Água Subterrânea/química , Medição de Risco , ÁguaRESUMO
Thermal springs are the sites where the water temperature lies above ambient temperature. They are widely used for power generation, hot water spas, balneotherapy, agriculture, laundering, and aquaculture. In Nepal, many thermal springs are reported but scientific understanding on water quality and hydrogeochemistry of the springs is very limited. In this study, a total of 28 physico-chemical parameters were measured in water samples collected from 12 thermal springs from Gandaki Province, Nepal. Correlation matrix and multivariate statistical analysis such as principal component analysis (PCA) and cluster analysis were used to understand the water quality and hydrogeochemistry of the hot water springs. The pH, temperature, electrical conductivity, total dissolved solids, and turbidity in the hot water springs ranged from 7.3 to 8.8, 31.6-64.3 °C, 206-16270 µS/cm, 115-6637 mg/L, and 0.21-63.7 NTU; respectively. The dominance order of major anions and cations were: Cl- > HCO3- > SO42- > NO3- > F- and Na+ > Ca2+ > K+ > Mg2+; respectively. Comparison of the water quality parameters with the WHO and National Water Quality Standards suggested that the majority of the parameters were within the safe limit. Out of 9 heavy metals and trace elements analyzed Zn2+, Ni2+, Cr3+, Cd+2, Hg (total), and Pb2+ were found below the safe limit but Fe (total), As (total) and Cu (total) were found higher than the WHO safe limit in total of 3, 5 and 1 sampling sites; respectively. The water quality index (WQI), sodium absorption ratio (SAR), and magnesium hazard (MH) ratio in the hot water springs ranged from 40.9 to 573, 2.2-49.3, 7.1-70.8; respectively. The result of PCA analysis showed that four principal components are required to explain hydrogeochemistry. Cluster analysis suggested that the sampling sites can be grouped into three distinct clusters based on total dissolved solids. Interestingly, the classification of hydrochemical facies using a Piper diagram suggested that 7 out of 12 thermal springs have Na-Cl type water. Finally, a perspective on the suitability of the hot springs for hot water spas and balneotherapy and policy recommendation is provided.
RESUMO
Wetlands are among the highly threatened ecosystems due to anthropogenic activities. The Ramaroshan Wetland Complex (RWC) of Achham District, Nepal is one of the high-altitude wetlands facing human induced degradation and loss. Herpetofauna are key bio-indicators of environmental health and habitat quality and are useful to assess habitat conditions of such threatened ecosystems. This study quantified the land use and land cover (LULC) change in the RWC and documented the diversity and distribution pattern of herpetofauna. The LULC in the area (13.94 Km2) was analyzed for 1989, 2000, 2010 and 2021 by supervised classification of remote sensing images. Surveys were conducted along 25 transects, each of 200 m in length and environmental variables were recorded for every observation of herpetofauna. The LULC analysis revealed an overall loss of 16% of the total water body between 1989 (0.25 Km2) and 2021 (0.21 Km2). Eleven species of herpetofauna (five amphibians and six reptiles) within five families and two orders (i.e., Anura and Squamata), were recorded with low diversity (H' = 1.88312) and evenness (E = 0.3642) indices. The herpetofauna had a hump-shaped distribution along the elevation gradient with the highest richness and abundance at 2300 m asl. Amphibian abundance decreased with increasing distance to nearest water sources, whereas reptile abundance increased. Amphibians were more abundant in agricultural field and marsh land, whereas reptile abundance was higher around human settlements. Results indicate that the wetland area in the RWC is declining at an alarming rate and, in turn, might account for the low diversity and abundance of the herpetofauna.
RESUMO
Unprecedented and unforeseen highly infectious Coronavirus Disease 2019 (COVID-19) has become a significant public health concern for most of the countries worldwide, including Nepal, and it is spreading rapidly. Undoubtedly, every nation has taken maximum initiative measures to break the transmission chain of the virus. This review presents a retrospective analysis of the COVID-19 pandemic in Nepal, analyzing the actions taken by the Government of Nepal (GoN) to inform future decisions. Data used in this article were extracted from relevant reports and websites of the Ministry of Health and Population (MoHP) of Nepal and the WHO. As of January 22, 2021, the highest numbers of cases were reported in the megacity of the hilly region, Kathmandu district (population = 1,744,240), and Bagmati province. The cured and death rates of the disease among the tested population are ~98.00 and ~0.74%, respectively. Higher numbers of infected cases were observed in the age group 21-30, with an overall male to female death ratio of 2.33. With suggestions and recommendations from high-level coordination committees and experts, GoN has enacted several measures: promoting universal personal protection, physical distancing, localized lockdowns, travel restrictions, isolation, and selective quarantine. In addition, GoN formulated and distributed several guidelines/protocols for managing COVID-19 patients and vaccination programs. Despite robust preventive efforts by GoN, pandemic scenario in Nepal is, yet, to be controlled completely. This review could be helpful for the current and future effective outbreak preparedness, responses, and management of the pandemic situations and prepare necessary strategies, especially in countries with similar socio-cultural and economic status.
Assuntos
COVID-19 , Pandemias , Controle de Doenças Transmissíveis , Feminino , Humanos , Masculino , Nepal/epidemiologia , Pandemias/prevenção & controle , Estudos Retrospectivos , SARS-CoV-2RESUMO
The response of native plants to allelopathic interference of invasive species may differ from species to species. In this study, the phytotoxic effects of Ageratina adenophora were tested on two native shrubs (Osbeckia stellata and Elsholtzia blanda) of Nepal. Both the shrubs were grown in pots under treatments of A. adenophora fresh leaves and root leachates, and litter. Then, the seedling length and biomass were compared among the treatments. The results show that A. adenophora litter has stimulatory effects but the leachates from fresh leaves and root are phytotoxic to the growth and development of native shrubs. Infrared Spectroscopy (IR) analysis confirmed the presence of O-H (Hydroxyl), N-H (Amines), C≡C (Alkynes), and C-H stretching (Aromatic) or C-O-C stretching (Ethers) in the leachates representing harmful allelochemicals. The invaded soil by A. adenophora had low pH and a high amount of organic matter, total nitrogen, phosphorus, and potassium than the uninvaded soil. The results indicate that the native O. stellata and E. blanda are harmed by A. adenophora in nature by leaching of allelochemicals and probably by reducing the soil pH. Overall, this study has provided valuable insights regarding the effects of A. adenophora invasion on native shrubs and revealing the potential mechanism of its invasiveness.
RESUMO
The academic sectors are badly affected by the COVID-19 pandemic globally. The studies regarding the implications of COVID-19 in education in Nepal were minimal, thus, this paper aims to highlight the impacts of the pandemic on the education sector of Nepal. It is revealed that the Nepalese academia has been facing problems due to lack of adequate and appropriate sustainable infrastructure for the online system, including skilled human resources. In addition, limited internet facilities in remote and rural areas were the other challenging tasks for virtual academic activities. Therefore, the concerned stakeholders should provide necessary services and appropriate strategies for virtual means of the education system to compensate the repercussion caused by the pandemic. This study could be helpful to identify the critical needs emerged due to the pandemic at present and in future and also contribute to adopt appropriate policy for the revival of educational institutions.
RESUMO
A comprehensive investigation was conducted on trace elements (TEs) in the glacier-fed Gandaki River Basin, Central Himalayas Nepal. A total of 93 water samples were collected from 31 locations in pre-monsoon, monsoon and post-monsoon seasons in 2016 to evaluate the concentrations of TEs. Multivariate statistical techniques such as analysis of variance, cluster analysis, principal component analysis, and correlation analysis were applied to investigate the spatiotemporal variations and identify the major sources of the TEs. The results classified most of the TEs into two groups. Group 1 including Cs, Li, Ni, Rb, Sc, Sr, Tl, U and V were from geogenic sources, while Group 2 including Cd, Co, Cr, Cu, Pb, Ti, Y and Zn were impacted by anthropogenic activities. Group 1 showed lower concentrations in the lower-middle and downstream segments with higher precipitation and the highest concentrations during pre-monsoon. In contrast, Group 2 demonstrated higher concentrations in the densely populated lower segments with more agriculture and industries, and the highest concentrations during the post-monsoon season. Comparing to the drinking water limits suggested that special attention should be paid to the elevated concentrations of Zn and As. The results of the study provide a basic guideline for future environmental protection in the Himalaya.
RESUMO
Strengthening the research of riverine mercury (Hg) export is of great significance for understanding the regional and global Hg cycle, especially for the data lacking trans-Himalayan rivers. In this study, three systematic sampling campaigns were conducted in the Koshi River Basin (KRB) during the post-monsoon, pre-monsoon and monsoon seasons. Hg speciation and distribution of river water were analyzed among the different seasons for a total of 88 water samples. The total Hg (THg) concentration of surface water in the KRB ranged from 0.64 to 32.96 ng·L-1 with an average of 5.83 ± 6.19 ng·L-1 and decreased in the order of post-monsoon (8.79 ± 7.32 ng·L-1) > monsoon (6.68 ± 6.12 ng·L-1) > pre-monsoon (2.18 ± 1.29 ng·L-1). Particulate Hg (PHg) accounted for 63% of THg on average and had a positive correlation with THg among all the three sampling seasons, indicating that the differences in PHg concentration were likely one of the main factors leading to the seasonal and spatial variations in THg in the KRB surface water. The annual Hg exports and fluxes were estimated to be 339.04 kg and 3.88 µg·m-2·yr-1, respectively. Furthermore, Hg export from the KRB had significant seasonal variation and decreased in the order of monsoon (259.47 kg) > post-monsoon (61.18 kg) > winter (9.31 kg) > pre-monsoon (9.08 kg), and this pattern was mainly related to seasonal changes in river runoff. The annual Hg export is projected to increase in the future, especially in the post-monsoon season. Therefore, more attention should be paid to river runoff observations and riverine Hg research for water resources management in the Himalaya.
RESUMO
Glacier runoff shows significant change under global warming in the headwater region of the Indus River with great impact on its highly populated downstream area, but the hydrochemistry characteristics of meltwater and the changing mechanism remain unclear in this region. In this study, runoff water samples were collected during May and June, 2015, from four glacial catchments in the Upper Indus Basin to investigate general characteristics and daytime dynamics of meltwater runoff together with sediment and chemical contents. Results showed that glacier runoff in the studied area had an alkaline pH and much higher sediment yields than the local average of the non-glacier areas. The carbonate-dominated geological feature in the four catchments resulted in single chemical facies of Ca-HCO3. The dominant process determining the glacier runoff chemistry was rock-water interaction, with less soluble minerals and less intensive evaporate weathering in the Passu and Gulmit catchments than the B&B and Hinarchi catchments. Comparing the investigated catchments, the larger glacier with longer flow path exhibited higher runoff but lower melting rate, higher SSC resulting from higher erosive power of flow, and higher solute concentrations as a consequence of more intensive contact of meltwater with rock minerals along the longer flow path. For individual catchments, a negative correlation between TDS and flow rate (R2 = 0.26~0.53) and changing trends of ion ratios with flow rate demonstrated that under intensive melting conditions, rock-water interactions were reduced, resulting in dilution of solutes. Overall, the general chemical characteristics of the investigated glacier runoff indicated geological control, whereas individual glacier illustrated hydrological control on the daytime dynamics of glacier runoff chemistry. The presence of glacier terminal lake and agriculture land can significantly alter the hydrochemistry of downstream runoff.
Assuntos
Monitoramento Ambiental , Camada de Gelo/química , Rios/química , Poluentes da Água/análise , Carbonatos/análise , Hidrologia , Água/química , Movimentos da Água , Tempo (Meteorologia)RESUMO
The Indus River Basin (IRB) with an area of 139,202 km2 is the lifeline river basin of Pakistan. An intensive study was conducted in six subcatchments of the IRB with five in the Upper Indus Basin (UIB) and one of the Lower Indus Basin (LIB; between Tarbela Dam and Panjand), i.e., the Gilgit River Basin (UIB-I), Hunza River Basin (UIB-II), UIB-III, UIB-IV and UIB-V, and LIB. A total of 84 surface water samples were collected from main stream and tributaries from June to August, 2016. The pH, electric conductivity (EC), and total dissolved solids (TDS) were measured in situ, whereas major ions (Ca2+, Mg2+, K+, Na+, Cl-, SO42-, and NO3-) and Si were analyzed in the laboratory. The results exhibited alkaline pH (8.55 ± 0.20) with diverse TDS (114.69 ± 77.65 mg L-1) and ion concentrations that were characterized primarily by the Ca-Mg-HCO3 type in the whole basin. The average TDS in the UIB and LIB were 93.99 ± 39.73 and 181.67 ± 167.82 mg L-1, respectively, under the influence of the arid to semi-arid climatic conditions and relatively higher anthropogenic interference in LIB compared to the UIB. The order of dominant major cations was different in the UIB and LIB, reflecting the diverse nature of geological formation. Gibbs plot, mixing diagrams, and ionic ratios were used to identify the controlling mechanism of river geochemistry in the IRB as carbonate weathering in general with different degrees of silicate weathering and minor contribution by evaporite dissolution. In addition, principal component/factor analysis also indicated that the major sources of dissolved loads in the basin are carbonates followed by silicates. Significant influences of silicate minerals were observed in the LIB, and there was a large contribution of evaporites in the UIB-II, UIB-III, and LIB. The suitability assessment showed that the river water fits the WHO permissible limits for drinking purposes from the perspective of major ions, whereas for irrigation purposes, most of the samples exhibited excellent and good levels except for a couple of permissible and doubtful levels from the Sawan and Deratang tributaries in the LIB, which may deteriorate the quality of soil and degrade the water quality downstream.
Assuntos
Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Rios/química , Poluentes Químicos da Água/análise , Abastecimento de Água/normas , Carbonatos/análise , Minerais/análise , Paquistão , Qualidade da Água/normasRESUMO
The characterization and assessment of water quality in the head water region of Himalaya is necessary, given the immense importance of this region in sustaining livelihoods of people and maintaining ecological balance. A total of 165 water samples were collected from 55 sites during pre-monsoon, monsoon and post-monsoon seasons in 2016 from the Gandaki River Basin of the Central Himalaya, Nepal. The pH, EC values and TDS concentrations were measured in-situ and the concentrations of major ions (Ca2+, Mg2+, K+, Na+, Cl-, SO42-, NO3-) and Si were analyzed in laboratory. Correlation matrices, paired t-test, cluster analysis, principal component analysis (PCA), the Piper, Gibbs, and Mixing plots, and saturation index were applied to the measurements for evaluating spatiotemporal variation of the major ions. The results reveal mildly alkaline pH values and the following pattern of average ionic dominance: Ca2+>Mg2+>Na+>K+ for cations and HCO3->SO42->Cl->NO3- for anions. The results of PCA, Gibbs plot and the ionic relationships displayed the predominance of geogenic weathering processes in areas with carbonate dominant lithology. This conclusion is supported by geochemically different water facies identified in the Piper plot as Ca-HCO3 (83.03%), mixed Ca-Mg-Cl (12.73.0%) and Ca-Cl (4.24%). Pronounced spatiotemporal heterogeneity demonstrates the influence of climatic, geogenic and anthropogenic conditions. For instance, the Ca2+-SO42-, Mg2+-SO42- and Na+-Cl- pairs exhibit strong positive correlation with each other in the upstream region, whereas relatively weak correlation in the downstream region, likely indicating the influence of evapo-crystallization processes in the upstream region. Analyses of the suitability of the water supply for drinking and irrigation reveal that the river has mostly retained its natural water quality but poses safety concern at a few locations. Knowledge obtained through this study can contribute to the sustainable management of water quality in the climatically and lithologically distinct segments of the Himalayan river basins.