Levels, sources and toxicity assessment of PCBs in surface and groundwater in Nigeria: A systematic review

Polychlorinated biphenyls (PCBs), which are produced by human activity, have contaminated Nigeria's ecology as a result of its industrialization for economic development. Organic compounds such as PCBs, are hazardous substances that provide significant health and environmental dangers. This study investigated the levels of PCBs in Nigerian ground and surface water, as well as their origins and associated health risks. A suitable screening process was used to gather and evaluate previous works from research databases, including PubMed, Google Scholar, ResearchGate, and Scopus. Both high and low quantities of PCBs were discovered in the research, and these findings pose an adverse effect on public health. The ground and surface water values ranged from below detectable limit (BDL) –560 µg/L and BDL–56.25 µg/L, respectively. Furthermore, transformer failures and oil spills were connected to the PCB sources. Additionally, leachates from waste sites, transformer oil, untreated effluent discharge, and petroleum spills were identified as the sources of PCBs. Through ingesting exposure routes to people, the cancer risk assessment values of PCBs in the water showed low to high-risk levels. Except for a single study, the non-carcinogenic risk's hazard index (HI) values showed no danger. It is advised that appropriate oversight, education, and stringent adherence to legal regulations be put in place to stop this hazardous substance from contaminating water and other environments.