Quantitative Assessment of Human Health Risks Associated with Heavy Metal and Bacterial Pollution in Groundwater from Mankweng in Limpopo Province, South Africa

Abstract

Heavy metal and microbial pollution in groundwater raises health concerns due to its adverse effects. This study aimed to assess the health risks associated with heavy metal and bacterial pollution in groundwater in Mankweng. Heavy metals and <i>Escherichia coli</i> were detected using inductively coupled plasma mass spectrophotometry and a Colilert system, respectively. The heavy metal pollution index (HPI) and non-carcinogenic and carcinogenic risks were computed. The β-Poisson dose-response model was employed to predict the probability of <i>E. coli</i> infection. The metals' concentrations were all within the permissible limits of the South African National Standard (SANS). However, Pb levels at sites E and G exceeded the World Health Organization (WHO) guideline (≤0.01 mg/L). HPI values were all less than 100, indicative of low contamination. The hazard quotient values were all less than 1, except for vanadium. The cumulative cancer risk ranged between 3.06 × 10^-5 and 1.81 × 10^-4 and between 3.55 × 10^-5 and 2.20 × 10^-4 for adults and children, respectively. <i>E. coli</i> was only detected at site L. The annual risk of <i>E. coli</i> infection exceeded the WHO risk limit of 10^-4. The results underscore the need for the regular monitoring of groundwater.