Water quality assessment along the segments of Bagmati River in Kathmandu valley, Nepal

Authors

  • Binod Baniya Land Surface Processes and Global Change Research Group, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China; Department of Environmental Science, Patan Multiple Campus, Tribhuvan University, Nepal; University of Chinese Academy of Sciences, Beijing 100049, China
  • Nitesh Khadka University of Chinese Academy of Sciences, Beijing 100049, China; Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China
  • Shravan Kumar Ghimire University of Chinese Academy of Sciences, Beijing 100049, China; Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China
  • Hom Baniya Department of Physics, Tri-Chandra College, Tribhuvan University, Kathmandu, Nepal
  • Shankar Sharma University of Chinese Academy of Sciences, Beijing 100049, China; National Tibetan Plateau Data Center, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China
  • Yam Prasad Dhital Institute of Eco-Chongming, Faculty of Earth Sciences, East China Normal University, Shanghai, China
  • Ranjana Bhatta Department of Environmental Science, Patan Multiple Campus, Tribhuvan University, Nepal
  • Bishnu Bhattarai Himalayan College of Agricultural Sciences and Technology, Balkhu, Kathmandu, Nepal

DOI:

https://doi.org/10.3126/njes.v7i0.34314

Keywords:

Bagmati River, Kathmandu valley, Nepal, Water pollution

Abstract

Identification of pollution in the river helps to know the state of the river ecosystem. The study aimed to assess the water quality of the Bagmati River by analyzing the physical and chemical condition and comparing it with national and international standards. The water samples were taken from 10 different sampling sites along the length of the Bagmati River inside Kathmandu Valley, i.e., from Sundarijal to Saibubhanjyang. A total of 30 physical and chemical parameters were examined. The results showed that the pH ranges from 6.0 to 7.5 in different sampling locations. The highest dissolved oxygen (DO) (8.5 mg/L) was found at the upstream while the lowest, i.e., 3.4 mg/L and 3.5 mg/L, was found at the urban core of the valley, i.e., Teku and Thapathali, respectively. The BOD, COD, oil, and grease considerably exceeded the WHO and national generic effluent standard. Most of the heavy metals in the river water were below the range of standard. The concentrations of all pesticides were found below 10 µg/L except heptachlor exoepoxide. The highest concentration of heptachlor exoepoxide (75 µg/L) was found at Balkhu, followed by Thapathali (69 µg/L) and Teku (62 µg/L). The result showed that the middle-urbanized segment, i.e., from Gokarna to Teku, is heavily polluted than the upstream and downstream segments of the river. The results are of great significance for policy formulation and implementation of the ecosystem restoration project of Bagmati River in the Kathmandu valley, Nepal.

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Published

2019-12-31

How to Cite

Baniya, B., Khadka, N., Ghimire, S. K., Baniya, H., Sharma, S., Dhital, Y. P., Bhatta, R., & Bhattarai, B. (2019). Water quality assessment along the segments of Bagmati River in Kathmandu valley, Nepal. Nepal Journal of Environmental Science, 7, 1–10. https://doi.org/10.3126/njes.v7i0.34314

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Section

Research Articles