Groundwater Quality Assessment Using Pollution Indices and Human Health Risks Through Exposure to Trace Elements in the City of Kara, Togo

This study assesses the concentrations of trace elements in groundwater from Kara, focusing on their implications for water quality and health risks. Groundwater samples were collected and analyzed during the dry and post-monsoon seasons for pH, TDS, and trace metals using standard methods and for calculating pollution indices and noncarcinogenic and carcinogenic risks. Groundwater was found to be fresh but more acidic during the dry season. Only As, Pb, Sb, Fe, and Mn exceeded acceptable limits in some samples, highlighting potential health risks. Based on the heavy metal pollution index, groundwater is unsuitable for domestic purposes for 16.67% and 4.17% of samples in dry and post-monsoon seasons, respectively. According to the degree of contamination, 37.5% in the dry season and 20.8% in post-monsoon fell in high pollution classes. Most samples presented a hazard index above the unity for the resident children and adults. Carcinogenic risk assessment scores exceeded 10 to 100-fold higher than the safe point of 10<sup>-6</sup>. Adequate access to treated and safe drinking water and regular monitoring are essential to mitigate these risks in the Kara region.