Environmental contamination and human health risk assessment of trace element exposure through diverse water sources

Human activities such as industrial effluents, agricultural run-off, and other land-based sources of pollution contaminate water with trace elements, posing threats to both the environment and human health. This study investigates concentrations of three trace elements, namely nickel (Ni), lead (Pb), and copper (Cu), in an assessment of health risks. The study comprised three different sources of water, namely surface water (SW), groundwater (GW), and industrial water (IW), sampled from six tehsils of District Bahawalpur, namely Bahawalpur, Bahawalpur Saddar, Hasilpur, Ahmedpur East, Yazman, and Khairpur Tamewali. A total of thirty water sampling sites, ten sites for each of the three types of water sources, were selected, and water samples were collected in the months of August, September, and October 2025. Results of the studied trace elements showed the highest concentrations in industrial water samples, followed by GW and SW samples (p < 0.001), with the highest concentration of Ni being 1.99 ± 0.20 mg/L, while that of Pb was 2.55 ± 0.11 mg/L and that of Cu was 3.24 ± 0.18 mg/L in IW samples. Significant differences were observed in the concentrations of the three studied trace elements in water samples as well as among the sampling sites of three types of water sources (p < 0.001). Estimated oral and dermal exposure (EEoral and EEderm) indicated low health exposure risks. However, THQoral values for Pb in GW and Ni, Pb and Cu in IW samples were found to exceed the acceptable threshold values. In addition to THQoral values, estimated cumulative non-carcinogenic health risks in the form of TTHQoral values for all three types of water sources under study were > 1 in all three water sources, suggesting potential risks. While, estimated carcinogenic health risks for the three types of water sources under study were found to be within the acceptable limits for all the studied health risks. This study provided a better understanding of various pollutants and their concentrations in water sources at the studied location.