Groundwater quality and potential health risks caused by arsenic (As) in Bhakkar, Pakistan

A groundwater investigation was carried out to assess geochemical factors that influence arsenic concentrations in the Bhakkar area, which is located along the Indus River in Punjab Province of Pakistan. The investigations indicated that concentrations of major ions in most of the analyzed samples were generally within the allowed limit proposed by WHO. A Piper plot indicated that the groundwater chemistry was dominated by bicarbonate, calcium and magnesium ions which are the main contributors to the total dissolved solids content of groundwater in the study area. A Gibbs plot showed that the dominant factor that influences the groundwater’s chemical composition is rock weathering. This study indicates that the concentration of arsenic is high in the groundwater samples of the study area, thus rendering groundwater not fit for drinking purposes. Arsenic concentrations range from 2 to 55 μg/L and about 73% of groundwater samples exceeded the arsenic limit proposed by WHO (10 μg/L). Arsenic concentration in upstream areas is less than downstream areas. Correlation coefficient matrix and principal component analysis were applied to find out the possible correlation of arsenic with different examined parameters of groundwater. Arsenic shows a strong negative correlation with iron (− 0.7) and potassium (− 0.65). Also, cancer risk and health assessment due to the presence of arsenic contamination were calculated based upon average daily dose, carcinogenic risk (CR) and hazard quotient (HQ). The risk assessment parameters indicated the potential carcinogenic and non-carcinogenic hazards related to the consumption of arsenic-contaminated water. The values of CR and HQ of As were up to 0.0023 and 5.13, respectively. Therefore, it is concluded that special monitoring of groundwater is needed in the Bhakkar area to protect the population from different diseases related to drinking As-rich contaminated groundwater.