Water pollution indexing and health risk assessment due to PTE ingestion and dermal absorption for nine human populations in Southeast Nigeria

Traditional human health risk assessment (HHRA) methods are now being replaced with advanced codes. In the present study, HERisk code and water pollution index (WPI) were employed for HHRA and water quality characterization of Umunya, a suburban in Nigeria. This study stands out from previous HHRAs performed in the region by applying the novel HERisk code, which evaluates health risk for nine human populations. The goal of this study was to provide a comprehensive report that will enlighten inhabitants and policymakers on the po-tential dermal and oral risks associated with the use of metal-contaminated water resources, for various age brackets, in the region. Standard methods were employed. With respect to measured physicochemical parame-ters, the WPI revealed that 66.7% of the water resources were unsuitable for human use. Based on the HERisk code, potentially toxic elements (PTEs) increased cancer risks in the following order: Ni > Pb > Cr. Total non-carcinogenic risks of drinking the water was found to be moderate. However, the cumulative risks due to dermal absorption of the contaminated water were negligible. The overall trend observed from the HHRA showed that older human populations in the area are less susceptible than younger populations. Nevertheless, it was detected that humans between ages 21 and 65 were less vulnerable than those older than 65 years. The findings of the HERisk code and WPI had a strong agreement, as water samples deemed less fit for human use by the WPI proved to have more health concerns. The WPI and HERisk code indicated that the most influential PTEs in the water were Pb and Ni, respectively. Thus, both PTEs expose water users to a higher risk of developing cancer via water ingestion.