Human Health Risks of Oil Spill Contaminants in Nigeria: A Systematic Review of Fish Contamination and its Impact on Public Health

The Niger Delta, a biodiversity-rich wetland and Nigeria's primary oil-producing region, has faced severe ecological degradation due to chronic crude oil spills over the past five decades. These spills have contaminated the air, ground, and water with toxic pollutants, leading to significant environmental and health issues. The region's mangrove forests, crucial for local ecosystems, have been particularly affected, with 5–10% destroyed due to oil spills, which also disrupt nutrient cycling and cause plant asphyxiation. This study quantifies contaminant loads and health risks across aquatic species in the Niger Delta. For example, Mugil cephalus (mullet fish) and Penaeus monodon (tiger prawn) showed high PAH hazard quotients (HQ) of 3.2 and 2.8, respectively, indicating carcinogenic risks. Conversely, Tympanotonus fuscatus exhibited low heavy metal HQs (0.1–0.3), suggesting minimal risk. High-risk species like Coptodon zillii (tilapia) contained lead and cadmium levels surpassing WHO limits by 300% and 180%, respectively. These findings highlight interspecies variability in contamination, correlating to neurotoxicity, organ damage, and cancer risks in communities reliant on high-risk species. The ecological-human health crisis underscores the need for bioremediation, targeted consumption advisories, and stricter environmental policies to mitigate long-term impacts.