Spatio-temporal hydrochemistry of two selected Ramsar sites (Rara and Ghodaghodi) of west Nepal

Rita Bhatta; Smriti Gurung; Rajendra Joshi; Shrija Tuladhar; Dikshya Regmi; Babi Kumar Kafle; Bed Mani Dahal; Nani Raut; Kumud Raj Kafle; Rabindra Kayastha; Archana Prasad; Lekhendra Tripathee; Rukumesh Paudyal; Junming Guo; Shichang Kang; Chhatra Mani Sharma

doi:10.1016/j.heliyon.2022.e11243

Spatio-temporal hydrochemistry of two selected Ramsar sites (Rara and Ghodaghodi) of west Nepal

Heliyon. 2022 Oct 26;8(11):e11243. doi: 10.1016/j.heliyon.2022.e11243. eCollection 2022 Nov.

Authors

Rita Bhatta^{1

2}, Smriti Gurung², Rajendra Joshi¹, Shrija Tuladhar², Dikshya Regmi³, Babi Kumar Kafle¹, Bed Mani Dahal², Nani Raut², Kumud Raj Kafle², Rabindra Kayastha⁴, Archana Prasad⁵, Lekhendra Tripathee^{6

7}, Rukumesh Paudyal^{6

7}, Junming Guo⁶, Shichang Kang^{6

8

9}, Chhatra Mani Sharma³

Affiliations

¹ Department of Chemical Science and Engineering, School of Engineering, Kathmandu University, Nepal.
² Department of Environmental Science and Engineering, School of Science, Kathmandu University, Nepal.
³ Central Department of Environmental Science, Institute of Science and Technology, Tribhuvan University, Kirtipur, Kathmandu, Nepal.
⁴ Department of Mathematics, School of Science, Kathmandu University, Nepal.
⁵ Central Department of Zoology, Institute of Science and Technology, Tribhuvan University, Nepal.
⁶ State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, China.
⁷ Himalayan Environment Research Institute (HERI), Nepal.
⁸ Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100085, China.
⁹ University of Chinese Academy of Sciences, Beijing 100039, China.

Abstract

The present study was conducted in two Ramsar sites, Lake Rara and Lake Ghodaghodi, of the western Nepal covering pre-monsoon and post-monsoon seasons of 2019 to find out the dynamics of the hydrochemistry. A total of 11 major ions (Na⁺, K⁺, Ca²⁺, Mg²⁺, NH₄ ⁺, F^-, Cl^-, SO₄ ^2-, NO₃ ^-, NO₂ ^-, HCO₃ ^-) along with six on-site parameters (temperature, pH, electrical conductivity, total dissolved solids, dissolved oxygen, and turbidity) were sampled in replicates from 18 sites in Lake Rara and 13 sites in Lake Ghodaghodi. Major ions were analyzed using ion chromatography including field and procedural blanks to maintain quality standards, whereas on-site parameters were measured by using standard multi-meter probes. The most dominant cation and anions were Ca²⁺ and HCO₃ ^- in both lakes indicating rock dominance through carbonate weathering as the primary source of dissolved ions in the lake waters. Further analysis indicated that Rara belongs to Ca(Mg)HCO₃ and Ghodaghodi belongs to Ca-HCO₃ type. The higher concentrations of Na⁺ and Cl^- during the post-monsoon indicates a possibility of long-range marine transport through monsoon precipitation.

Keywords: Major ions; Physicochemical parameters; Seasonal variation; Water quality.