Water quality and health risk assessment based on hydrochemical characteristics of tap and large-size bottled water from the main cities and towns in Guanzhong Basin, China

The hydrochemical characteristics, water quality, and health risk of tap water and large-size bottled water collected from major cities and towns in Guanzhong Basin in China were investigated. Physical and hydrochemical characteristics of the water samples were identified. The entropy weighted water quality index (EWQI) method was used to evaluate the quality of the water samples. Health risk assessments for the waters were also made to find if they were qualified enough to serve as drinking water. Results show that F and As are the major toxic chemical substances to human health in tap water in the study area. The non-carcinogenic risks of F in those tap water samples with excessive F are unacceptable for children. High fluoride in tap water probably originates from groundwater. And 5 tap samples, accounting for 13% of all the tap water samples, may pose non-carcinogenic risks of As. Particularly, the carcinogenic risks posed by As in tap water are more serious than the non-carcinogenic risks. In comparison to the tap water, the large-size bottled water has a better quality and poses no health risk. Therefore, it can be considered a suitable alternative to the tap water in the study area. In addition, such measures as water source alteration and more effective pretreatment should be taken in localities where tap water has potential health risks associated with F and As.