Associations of potentially toxic elements (PTEs) in drinking water and human biomarkers: a case study from five districts of Pakistan.

Potentially toxic elements (PTEs) are hazardous contaminants with great global environmental/ecological concerns due to their toxic, persistence, and bio-accumulative nature. This study investigates the concentrations of PTEs (Cd, Co, Cu, Fe, Ni, Mn, Pb, and Zn) in drinking water sources and consumers' biomarkers such as hair, nails, urine, and blood. For this purpose, drinking water (n = 190) and consumer biomarker (n = 60) samples were collected from five districts of the Southern Khyber Pakhtunkhwa, Pakistan. Samples were extracted and analyzed for selected PTEs concentrations using an inductively coupled plasma mass spectrometer (ICP-MS, PerkinElmer Optima 7000 DV, USA). The concentrations of PTEs were observed within the drinking water guidelines set by the World Health Organization (WHO), except for Fe, Mn, and Pb. The determined concentrations of PTEs were used to evaluate the health risk through exposure, particularly hazard quotient (HQ) and hazard index (HI). The PTEs contamination of drinking water has led to the highest mean ADI values (39.0 and 91.8 μg/kg/day) and HQ values (0.306 and 0.130) for Zn in adults and children, respectively. The mean values of HQ and HI for selected PTEs were observed within the safe health limits (< 1). Among studied biomarkers, hair showed the highest concentrations for Mn, Zn, Cd, and Pb, plasma for Co and Cu, nails for Ni, and red blood cells (RBCs) for Fe only. This study concluded that chronic exposure of PTEs through drinking water consumption has led to their bioaccumulation in human biomarkers.