scholarly journals Water Quality Degradation in the Lower Mekong Basin

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1555
Author(s):  
Ratha Sor ◽  
Peng Bun Ngor ◽  
Savoeurn Soum ◽  
Sudeep Chandra ◽  
Zeb S. Hogan ◽  
...  

The Mekong River is one of the world’s largest rivers, unparalleled in terms of its biodiversity and ecosystem services. As in other regions, sufficient water quality is required to support diverse organisms, habitats, and ecosystems, but in the Mekong region, water quality has not been well studied. Based on biological and physical-chemical data collected over the last two decades, we evaluated spatial-temporal water quality of the Lower Mekong Basin (LMB) using biotic and abiotic assessment metrics. We found that during the 2000s, water quality in the LMB was unpolluted, with “very good” metrics for tributary rivers and “good” status for mainstem rivers. However, during the last decade, water quality has been degraded in the LMB, particularly near Vientiane City; the Sekong, Sesan, and Srepok (3S) Rivers; the Tonle Sap Lake system; and the Mekong Delta. Water quality degradation likely corresponds to flow alteration, erosion, sediment trapping, and point and non-point wastewater, which have occurred from rapid hydropower development, deforestation, intensive agriculture, plastic pollution, and urbanization. Regular biomonitoring, physical-chemical water quality assessment, transparent data sharing, and basin-wide water quality standards or management are needed to sustain water quality to support biodiversity and ecosystem function in the LMB.

Author(s):  
Mushtaq Ahmed Nizamani

Keenjhar Lake is the main source of drinking water for the metropolitan city of Karachi. The release of untreated wastewater from Kotri industrial area and other sources have made the lake water polluted. This study was subjected to determine the impacts of such pollutant sources on the water quality of Keenjhar Lake. The study involves the analysis of water quality parameters of Keenjhar Lake and its Feeding source (KB Feeder). The sampling sites were selected based on the sources of contamination. The water samples are tested for physical, chemical and microbiological parameters. The result of water analysis indicates the contamination level of the lake is quite alarming for the sites of Kotri effluent and WAPDA colony where Total Dissolved Solids (TDS), Chloride and other ionic metals were quite higher in concentration than other sites. These sites are also contaminated with Fluoride and Arsenic which are carcinogenic elements. The study reveals that the contamination level of feeding source is causing big non-reversible damage to the lake if continued to be uncontrolled. This contamination is mainly due to the release of toxic metals and ions in the KB feeder caused by human carelessness.


Author(s):  
Engr. Furqan wali

In this paper, the authors analyze the drinking water quality of Peshawar city due to which authors concluded that water quality assessment of 18 locations inside Peshawar of various union council. Groundwater samples were collected from a tube well and subjected to physical, chemical and biological analysis to check their suitability for the purpose of drinking. Results exposed that out of 18 samples 10 samples of water were found unfit for drinking purposes. In the 10, samples most of the effect on the water quality was from the chemical and biological contamination. It is concluded that the old defective supply system, infrastructure and storage, as well as their lack of maintenance are the reason behind the pollution of drinking water in Peshawar.


Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3522
Author(s):  
Vanna Nuon ◽  
Sovan Lek ◽  
Peng Bun Ngor ◽  
Nam So ◽  
Gaël Grenouillet

The Mekong River is one of the world’s largest rivers and has an annual captured fish production of about 2.3 million tonnes, equivalent to around 11 billion USD. Although the Mekong provides important ecological and socioeconomic benefits to millions of people, it is facing intensive change due to anthropogenic stressors. Therefore, it is necessary to understand the changes to the spatiotemporal fish communities to inform sustainable fisheries management. Here, we aimed to characterize patterns of the fish communities and identify the ecological status of each fish community using daily catch data from 2007 to 2018 at 25 monitoring sites in the Lower Mekong Basin (LMB). The collected data were classified by a self-organizing map into four main groups. Group 4 represented the lower Vietnam Mekong Delta (VMD), while groups 1, 2, and 3 were subdivided into subgroups 1a (upper LMB), 1b (upper and middle LMB), 2a (Mekong River below the Khone Falls and Sesan River), 2b (Mekong River below the Khone Falls and Sekong, Sesan and Srepok (3S) Rivers), 3a (Floodplain-Tonle Sap and Songkhram) and 3b (upper VMD). Among the 571 species recorded, 119 were identified as indicator species. Based on the abundance and biomass comparison curves, the fish community of 2b was in a healthier condition with a positive W-statistic value while the rest had a negative W-statistic value. The highest species richness and diversity were observed in 3a and 2b, so these subgroups deserve high management and conservation priority. Likewise, 1a should also be considered as a high priority area since it harbors several endangered and long-distant migratory fishes. It was also noticed that the fish communities of groups 3 and 4, located far from the hydropower dams, remained mostly unchanged compared to those of groups 1 and 2, close to the mainstream and tributary dams in the upper LMB and 3S Rivers.


2020 ◽  
Vol 13 (5) ◽  
pp. 2447
Author(s):  
Reinaldo Brandi Abreu Bifano ◽  
Catarina Da Rocha Marcolin ◽  
Maria Otávia Silva Crepaldi ◽  
Raquel Viana Quinelato ◽  
Adriana Tiemi Ramos Okumura ◽  
...  

Este estudo teve como objetivo avaliar a qualidade da água das microbacias dos rios Jardim e Mutari, situadas no Extremo Sul da Bahia, através da avaliação de parâmetros físicos, químicos, microbiológicos e do uso e ocupação da terra. Para isso foram realizadas quatro coletas, em abril, maio, julho e outubro de 2019, em 8 pontos amostrais, selecionados de acordo com possíveis fontes pontuais e difusas de poluição. Foram analisados os parâmetros temperatura, potencial hidrogeniônico (pH), salinidade, oxigênio dissolvido (OD), demanda bioquímica de oxigênio (DBO), nitrito, nitrato, amônia, nitrogênio total (NT), fósforo total (PT), sólidos dissolvidos totais, coliformes totais e termotolerantes, que foram comparados com o estabelecido pela CONAMA n° 357/2005. Já as análises de uso e ocupação da terra, foram realizadas utilizando o software QGIS. Com os resultados obtidos observou-se que os parâmetros pH, OD, DBO, PT e NT apresentaram valores em desacordo com o permitido pela legislação, principalmente nos pontos próximos às áreas urbanizadas. A análise estatística multivariada PCA, permitiu identificar diferenças na qualidade da água das microbacias no período seco e chuvoso.Já o teste Kruskal-Wallis indicou diferença significativa entre os ambientes analisados. Nossos resultados indicam que é de suma importância a tomada de ações por parte do poder público que visem minimizar os impactos causados pelo uso e ocupação desordenada da terra e atividades agrícolas na qualidade da água dessas bacias hidrográficas. Cabe destacar também a importância de ações voltadas a educação ambiental principalmente da população ribeirinha.  Water Quality Assessment in Hydrographic Watersheds in the Extreme South of Bahia, BrazilA B S T R A C TThis study aimed to evaluate the water quality of the Jardim and Mutari rivers, located in southern Bahia, by means of evaluating physical, chemical and microbiological parameters and land use and occupation. Four campaigns were carried out in April, May, July, and October, 2019, at 8 stations, selected according to possible punctual and diffusive sources of pollution. The water quality results were compared with that established by CONAMA n.º 357/2005and the Water Quality Index (IQA) was calculated from these. For data analysis, Principal Component Analysis (PCA) was also performed and Kruskal-Wallis tests were applied, using the PAST software.The land use and occupation analyses were performed using the QGIS software. We observed that the pH, OD, DBO, PT and NT were in disagreement with those allowed by the legislation, mainly near urban areas. The multivariate statistical analysis PCA, allowed to identify differences in the water quality of the watersheds in the dry and rainy period. The Kruskal-Wallis test indicated a significant difference between the environments analyzed.The supervised classification confirmed the need to recover areas along the riverbed within the analyzed micro-basins.Our results indicate it is crucial that public authorities act to minimize the impacts caused by the disorderly urban occupation and agricultural activities. It is also worth mentioning the importance of actions aimed at environmental education, mainly of the riverside population.Keywords: water quality, physical, chemical and biological parameters, hydrographic basins, rivers. 


Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1948
Author(s):  
Flavia Tromboni ◽  
Thomas E. Dilts ◽  
Sarah E. Null ◽  
Sapana Lohani ◽  
Peng Bun Ngor ◽  
...  

Establishing reference conditions in rivers is important to understand environmental change and protect ecosystem integrity. Ranked third globally for fish biodiversity, the Mekong River has the world’s largest inland fishery providing livelihoods, food security, and protein to the local population. It is therefore of paramount importance to maintain the water quality and biotic integrity of this ecosystem. We analyzed land use impacts on water quality constituents (TSS, TN, TP, DO, NO3−, NH4+, PO43−) in the Lower Mekong Basin. We then used a best-model regression approach with anthropogenic land-use as independent variables and water quality parameters as the dependent variables, to define reference conditions in the absence of human activities (corresponding to the intercept value). From 2000–2017, the population and the percentage of crop, rice, and plantation land cover increased, while there was a decrease in upland forest and flooded forest. Agriculture, urbanization, and population density were associated with decreasing water quality health in the Lower Mekong Basin. In several sites, Thailand and Laos had higher TN, NO3−, and NH4+ concentrations compared to reference conditions, while Cambodia had higher TP values than reference conditions, showing water quality degradation. TSS was higher than reference conditions in the dry season in Cambodia, but was lower than reference values in the wet season in Thailand and Laos. This study shows how deforestation from agriculture conversion and increasing urbanization pressure causes water quality decline in the Lower Mekong Basin, and provides a first characterization of reference water quality conditions for the Lower Mekong River and its tributaries.


2006 ◽  
Vol 54 (11-12) ◽  
pp. 47-55 ◽  
Author(s):  
S.-W. Liao ◽  
J.-Y. Sheu ◽  
J.-J. Chen ◽  
C.-G. Lee

Factor analysis was conducted to explain the characteristics and variation in the quality of water during the disassembly of oyster frames and fishery boxes. The result shows that the most important latent factors in the Tapeng Lagoon are the ocean factor, the primary productivity factor, and the fishery pollution factor. Canonical discriminant analysis is applied to identify the source of pollution in neighbouring rivers outside the Tapeng Lagoon. The two constructed discriminant functions (CDFs) showed a marked contribution to all the discriminant variables, and that total nitrogen, algae, dissolved oxygen, and total phosphate combined in the nutrient effect factor. The recognition capacities in these two CDFs were 95.6% and 4.4%, respectively. The water quality in the Kaoping river most strongly affected the water quality in the Tapeng Lagoon. Disassembling the oyster frames and fishery boxes improved the water quality markedly. However, environmental topographic conditions indicate that strengthening stream pollution prevention and constructing another entrance to the ocean are the best approaches for improving the quality of water in the Tapeng Lagoon by reducing eutrophication. These approaches and results yield useful information concerning habitat recovery and water resource management.


2018 ◽  
Vol 10 (5) ◽  
pp. 1373-1392
Author(s):  
Taina Turial da Silva ◽  
Kamila Soares do Espírito Santo ◽  
Silvia T. Matsumoto ◽  
Josimar Ribeiro

2016 ◽  
Vol 19 (2) ◽  
pp. 107-117
Author(s):  
Trang Thi Thuy Nguyen ◽  
Khoi Nguyen Dao

The objective of this study was to simulate the hydrologic characteristic and water quality of 3S rivers system (Sekong, Sesan and Srepok) using SWAT model (Soil and Water Analysis Tool). Agriculture and forest are the main land use types in this basin accounting for more than 80 % of the total area. Therfore, nitrogen and phosphorus were selected to be parameters for water quality assessment. SWAT-CUP model was applied to calibrate the model for stream flow and water quality based on SUFI-2 (Sequential Uncertainty Fitting version 2) method. The model performance has been assessed by three statistical indices, including coefficient corellation (R2), Nash-Sutcliffe efficient coefficience (NSE) and percentage Bias (PBIAS). The results showed that SWAT model was well calibrated for simulating the streamflow and water quality with the values of R2 greater than 0.5 except for the Attapeu and Kontum stations, and of PBIAS less than 10 % and 35 % for streamflow and water quality, respectively. The well-calibrated SWAT model can be applied in predicting the hydrology and water quality for other application. Furthermore, it is a tool supporting the policy makers to offer a suitable decisions regarding the sustainable river basin management.


Author(s):  
Akhand Archna ◽  
Shrivastava Sharad ◽  
Akhand Pratibha

The water quality of River Kshipra in stretch of 195 km was studied for water quality status using benthic macro invertebrates for all three seasons’ monsoon, winter and summer. The River water quality is subject to severe domestic and industrial pollution at compete stretch of River. In the present investigation a total of 13 Orders of macrobenthic fauna i.e. Ephemeroptera, Trichoptera, Placoptera, Coleoptera, Hemiptera, Odonata, Crustacea, Diptera, Pulmonata, Operculata, Pulmonata, Oligochaeta and Hirudinea belong to 3 Phylum’s Arthropoda, Mollusca and Annelida were reported. Arthropoda was the most dominant group in all seasons. On seasonal comparison of benthic fauna is observe that abundance were decreasing order were, Winter > Monsoon > summer. To monitor the water quality samples from two years (2010-12) from different stations were collected monthly. The works highlighted the condition of the River water in various seasons with respect of the seasonal abundance of the benthic macro-invertebrates organisms mentioned above.


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