Evaluation of drinking water quality in restaurants of Gazipur city using water quality indices and multivariate analysis

Abstract

Groundwater is a vital source for drinking purposes in Gazipur area. In this present study, 173 samples are collected from different restaurants divided into 18 zones across Gazipur city area. Thirteen physicochemical parameters like pH, Color, Turbidity, DO, TDS, Cl(residual), F, Hardness as CaCO3, Fe, Mn, NO3, SO42-, NH3 are used for analysis. From these parameters DO, TDS, Mn, Hardness, pH value exceed the standard limit. These eighteen zones of Gazipur city are divided into three clusters as cluster I (8 zones), cluster II (2 zones), and cluster III (8 zones) by the homogeneity of samples. The dominant water types in Cluster, I is (Color-Iron-Nitrate-Ammonia) type of water, cluster II (Chlorine-Fluoride-Sulfate) type of water, and cluster III (Hardness-pH-TDS-DO-Turbidity) type of water. Three water quality Index models like Integrated Water Quality Index, Assigned Weight Water Quality Index, and Weighted Arithmetic Water Quality Index are used to evaluate Water quality. The IWQI and Weighted Arithmetic Water Quality Index reveal that 31% and 49% of the total sample mostly fall into the unsuitable category. But Assigned Weight Water Quality Index model categorized 2% of total samples as unsuitable. Pearson correlation matrix shows strong positive correlation between TDS-EC (0.987) has strong positive correlation and Color-Manganese (0.292) has moderate positive correlation in cluster I. In cluster II TDS-EC (0.994), Color-Manganese (0.704) show a strong positive correlation, but PH-color (-0.769), Fluoride-Nitrate (-0.828) shows negative correlation & there is no strong correlation in cluster III. In Cluster, I, Cluster II, Cluster III total cumulative variance can be explained 73.095%, 91.335% & 68.013% respectively by the result of factor analysis. Three Clusters’ components eigenvalue is greater than 1 are respectively Cluster I (six factors), Cluster II (five factors) and Cluster III (six factors). The strong factor loadings in three Clusters are TDS, EC, Hardness, Color, Nitrate, Turbidity, Mn, Fluoride, Ammonia, Iron to contaminate the environment. Factor analysis predicts the source of groundwater pollution which consist of effluent from textile industries, combine mill, pharmaceutical industries, nitrogenous fertilizer in agricultural area, rock and water interaction in the study area. In future, Gazipur city will become more densely populated that will create more contamination in water. A high number of industries containing much population damaging surface water as well as ground water. It damages human health with the environment while drinking regularly. That’s why we have tried to analyze the present scenario of drinking water of Gazipur region. Management and investigation of groundwater quality in a proper way helps to supply good quality of drinking water in the restaurants of Gazipur City.