Contamination, sources and health risk assessment of PAHs in surface and underground water in Nigeria: a review

The industrialization of Nigeria for economic development has led to the pollution of the ecosystem by polycyclic aromatic hydrocarbons (PAHs) through anthropogenic activities. PAHs are toxic organic compounds, ubiquitous and can pose a health-related environmental risk. The sources, concentration, and health risk assessments of PAHs in underground and surface water in Nigeria were reviewed in this study. Previous studies were extracted from research databases (PubMed, Google Scholar, ResearchGate, and Scopus) and appropriately screened. The PAH levels found in the studies were at low and high concentrations and could pose a health-related risk to the populace. The values ranged from ND–17,762 to ND–450,000 µg/L for underground and surface water, respectively. Also, the sources of the PAHs were pyrogenic and petrogenic. The cancer risk assessment values of PAHs in the water recorded low to high-risk values via dermal and ingestion exposure routes to humans. The hazard index (HI) values of the non-carcinogenic risk observed no risk except for only one study. It is recommended that proper monitoring, awareness, and strict enforcement of regulatory laws be implemented to prevent water and environmental pollution by this toxic compound.