Hydrochemical assessment of the Beeshazar and associated lakes in Central Nepal

Abstract

Water quality deterioration has threatened aquatic life around the world including Nepal, which has been a serious issue for environmental sustainability and economic development. This study evaluated and interpreted hydrochemical parameters of the Beeshazar and associated lakes in Central Himalaya, Nepal. The study revealed that the water in the lake was slightly alkaline as the average pH was 7.52. The correlation and principal component analysis (PCA) identified both geogenic and anthropogenic processes as the controlling factors of hydrochemistry whereas the cluster analysis (CA) showed relatively more pollution in the associated Laxmi Lake. Also, the water quality index (WQI) classified the water as “good” for drinking purposes (i.e., WQI = 33.90), while the pollution index (PI) values were characterized as sub-cleanness and slightly polluted. In general, both the WQI and PI signify that water in the lake complex is currently safe for drinking purposes. It is further confirmed from the comparative analysis of chemical variables with other lakes in the region, WHO and national water quality guidelines for aqua culture that the most of the analyzed water parameters exhibited relatively low concentrations and were within the prescribed guidelines. However, the elevated concentrations of NO3− and PO43− may pose serious problems for retaining water quality in the future. The results could be considered for future planning and management of the Ramsar Lakes of the lowland areas in the Himalaya and also as a valuable reference for the freshwater researchers at the national and international levels.