Characterization and health risk assessment of arsenic in natural waters of the Indus River Basin, Pakistan

The elevated concentrations of arsenic in natural water are one of the major environmental threats to human health. However, the existing characteristics, controlling mechanisms, and associated risks of arsenic in natural waters in the Indus River Basin (IRB), Pakistan, are yet to be unequivocally understood. In this study, a total of 203 samples of surface water (SW), shallow groundwater (SGW), and deep groundwater (DGW) were collected from the IRB to assess the geochemical characteristics of arsenic and its associated health risks, as all three kinds of waters are the main sources of drinking and domestic usage. The results revealed that the arsenic concentrations in the SW, SGW, and DGW were in the ranges of 1.1-26.45, 1.05-44.44, and 0.67-41.09 mu g L-1, respectively. Furthermore, the predominance of As (V) (97 %) over As (III) (3 %) confirmed that the desorption of As in oxidizing environments with elevated pH and Eh is the controlling mechanism. The hazard quotient of 11-45 % and 20-60 % samples and cancer risk of 26-64 % and 26-68 % samples indicated high health risks for the adults and children, respectively, suggesting an immense need for appropriate measures of reducing natural water arsenic concentrations in IRB from the human health perspectives.

Automated summary

This study assessed the geochemical characteristics and associated health risks of arsenic in natural waters in the Indus River Basin (IRB), Pakistan. A total of 203 samples of different water types were collected and analyzed. The results showed that arsenic concentrations in the waters ranged from 1.1-26.45, 1.05-44.44, and 0.67-41.09 μg/L for surface water, shallow groundwater, and deep groundwater, respectively. The desorption of arsenic in oxidizing environments with elevated pH and Eh was identified as the controlling mechanism.