Health risk assessment induced by trace toxic metals in tap drinking water: Condorcet principle development

Abstract

Acute exposure to trace metals (TMs) in water is hazardous to human health. The average concentrations (Cavg.) and carcinogenic (CAR) and non-carcinogenic (non-CAR) risks of eight TMs to World Health Organization's (WHO) guidelines and national standard limits (NSLs)were determined. The Cavg. and (the range) of As, Hg, Cd, Pb, Co, Cr, Ni, and Zn were measured as 4.29 ± 0.57 μg L−1 (1.12–10.27 μg L−1), 0.22 ± 0.10 μg L−1 (ND-1.05 μg L−1), 0.31 ± 0.18 μg L−1 (ND-1.80 μg L−1), 4.66 ± 0.32 μg L−1 (0.10–14.22 μg L−1), 24.61 ± 4.65 μg L−1 (3.11–67.25 μg L−1), 16.86 ± 5.54 μg L−1 (5.12–34.61 μg L−1), 14.07 ± 4.37 μg L−1 (3.79–31.39 μg L−1), and 268.42 ± 75.82 (87.29–561.22 μg L−1), respectively. The Cavg. of Co and Hg exceeded the WHO and NSLs. The non-CAR risk assessment was used to order the TMs according to the total target hazard quotient (TTHQ) As > Pb > Cr > Co > Zn > Hg > Ni > Cd. None of the investigated age groups are at risk As there is a low Cavg of all trace metals (i.e., the THQ is > 1). The age groups were ranked based on THQ and incremental lifetime cancer risk (ILCR) As < 1 year, >1–10 years, > 11–19 years, and > + 20 years. The ILCR of As for all the age groups was >10−4, whereas for Pb it was <10−6. Cumulative carcinogenic risk (CCR) for As and Pb was at a safe threshold risk (>10−4) for all the age groups.