Physicochemical parameters, heavy metal pollution and health risk assessment of water bodies in Kolokuma/Opokuma Local Government Area of Bayelsa State

Water bodies in Bayelsa state are affected by pollution, which makes them unfit to drink and seriously disturbs aquatic life and ecosystems. This study examined physicochemical parameters and health risk assessment of heavy metals in the drinking water sources in Odi and Kaiama of Kolokuma/Opokuma Local Government Area (KOLGA) of Bayelsa State, Nigeria. Four (4) water samples were obtained from underground (borehole), River, Agbayai Lake, and dugwell. The samples were analysed using standard laboratory methods. The possible harmful health effects of exposure to heavy metals content in the water samples were also estimated using reliable tools of health risk assessment indices. The physicochemical parameters showed that the range values of pH, temperature, total dissolved solids, dissolved oxygen, biological oxygen demand, chloride, sulphate, nitrate, and phosphate were within the standards of the United States Environmental Protection Agency (USEPA), Nigerian Industrial Standard (NIS), and WHO permissible limits (P<0.05). Compared to lead detected in underground (0.023 mg/mL) and dug-well (0.033 mg/mL) water and iron detected in River water (0.738 mg/mL), which were above the permissible limits, cadmium, chromium, zinc, copper, and manganese were below the allowable limit. The health risk assessment results showed that children are more vulnerable to health risks. The average exposure dose through ingestion (LADDing) for all the metals in the water samples was above the acceptable limit, while the dermal exposure dose (LADDderm) for all the metals revealed in the water samples was within the USEPA acceptable range of 1x10-6 to 1x10-4 . The oral and dermal accumulativecarcinogenic risk (Rtotal) values for Cd, Cr, and Pb highlighted long-term risks. From the present study, it is important to track the exposure levels and consistently revise risk assessments to ensure the safety of water resources in the Niger Delta environment and to protect the health of the population.