Assessment of Bhatiari Lake water quality: Pollution indices,hydrochemical signatures and hydro-statistical analysis

This study aimed at evaluating the water quality of Bhatiari Lake (BL) for the first time based on water quality parameters, pollution indices, hydrochemical signatures and hydro-statistical analysis. Lake water samples were collected from the lake during April–May 2019 and wide ranges of parameters were considered for the investigation. Except for COD and Fe, all the parameters were within the permissible limit. COD crossed Bangladesh standards and testing institution (BSTI) and United States environmental protection agency (USEPA) standards. In contrast, Fe crossed World health organization (WHO), Bureau of Indian Standards (BIS) and USEPA standards. Hydrochemical analysis indicated the water as soft-fresh where near neutral low-metal was noticed from the Ficklin-Caboi diagram. Ca²⁺-Mg²⁺-HCO₃^- type water was confirmed from Piper and Chadha diagram, whereas Durov and Schoeller's diagram were indicated the influence of Mg²⁺-HCO₃^-. The trend of cations and anions were Ca²⁺> Mg²⁺> Na⁺>K⁺ and HCO₃^? > Cl^? > NO₃^? > SO₄^2? > PO₄^3? as stated by pie chart. Most precipitation dominant water was confirmed from the Gibbs diagram. Principal component analysis (PCA), Cluster analysis (CA) and Correlation matrix (CM) indicated the co-existence of geogenic and anthropogenic sources for pollution. Good water quality was observed via an integrated approach namely degree of contamination (C_d), Single-Factor Pollution Index (SPI), Comprehensive pollution index (CPI), Heavy metal evaluation index (HEI), Heavy metal pollution index (HPI), Nemerow's pollution index (NPI) and Ecological risk index (ERI). In addition, water quality index (WQI) remarked the water is excellent. Taken collectively, the present study indicates the BL water can be considered pollution-free.