Health risk assessment and provenance of arsenic and heavy metal in drinking water in Islamabad, Pakistan

This study investigated arsenic (As) and heavy metal (HM) contamination of drinking water sources in Islamabad, Pakistan. For this purpose, samples (n=60) were collected from various drinking water sources (bore wells, tube wells, tap, filtration plant, and bottled water). The physicochemical parameters of samples were analyzed, including basic parameters such as pH; electrical conductivity; total dissolved solids; anions: fluoride, chloride, and As; and HM: Pb, Cd, Ni, Zn, and Fe. Results revealed that the concentrations of Pb, Cd, Ni, Fe, and As surpassed the drinking water guidelines of the World Health Organization (WHO) by 23.3%, 6.67%, 1.67%, 20.0%, and 3.34%, respectively. The chronic risk posed by exposure to the measured As and HM concentrations were evaluated by calculating the average daily dose (ADD), hazard quotient (HQ), and carcinogenic risk (CR). The results revealed that HQ values were <1 for HM; however, that of As was >1 for drinking water for children (in 3.34% samples). The CR posed by As consumption surpassed the United States Environmental Protection Agency (USEPA) threshold limits of (1.0E-04 to 1.0E-06). Statistical analyses such as Pearson correlation and principal component analyses suggested that drinking water contamination was attributable to both anthropogenic and geogenic activities. (C) 2020 Elsevier B.V. All rights reserved.