Physicochemical characteristics and statistical analysis of groundwater (Drinking) quality parameters in the rural area of Dewanganj, Nepal

• A total of 11 groundwater quality parameters, like conductivity, turbidity, pH, TDS, hardness, alkalinity, chloride, sulfate, nitrate, total coliform and arsenic have been statistically analyzed. • The turbidity and arsenic values crossed the WHO guidelines value. • The mean, coefficient of variance, standard deviation, and minimum and maximum values were computed. • Correlation and regression analyses simplified the complexity of variations by quantifying how strongly and in which direction two variables have a linear relationship. The degradation and contamination of groundwater is a big problem for the residents of Dewanganj, Nepal, because of the heavy use of fertilizer, fungicides, insecticides, wastewater discharge, people’s ignorance, government’s negligence, and the widespread groundwater withdrawal. So there is the need for advanced statistical approaches to assess water quality analysis. This research evaluates the physicochemical characteristics and statistical analysis of 11 groundwater quality parameters in the selected area. The results show that the pH, conductivity, chloride, total hardness, and total alkalinity were within the permissible limit of WHO guidelines. However, turbidity values of some samples of wards no. 1, 2, 4, 5, 6, and 7 are up to 30.396 ± 25.35 NTU and cross the WHO guidelines value of 5 NTU. Also, the arsenic value of wards no. 1, 5, 6, and 7 is found to be up to 0.022 ± 0.004 mg/L and is found to cross the WHO guidelines value of 0.01 mg/L. The correlation and regression analyses simplified the interpretation and complexity of variations by highlighting the most significant variables and also quantifying how strongly and in which direction two variables have a linear relationship. The results of the statistical analysis, indicate that the conductivity shows a strong positive correlation with TDS (r = 0.908) and a strong negative correlation with SO₄²⁻ (r = -0.863). Total hardness has a strong positive correlation with TDS (r = 0.815) and a moderate correlation with SO₄²⁻ (r = -0.765). Total alkalinity data indicates a strong negative correlation with As (r = -0.858) and SO₄²⁻ (r = -0.819) but a strong positive correlation with TC (r = 0.844). Arsenic and sulfate have a strong negative correlation with TC (r = -0.811) and (r = -0.94), indicating how water chemical parameters impact bacterial content. The above relationships between various water quality parameters are further validated by regression analysis with linear first-degree equation.