Human Health Risk Assessment of Heavy Metal and Polycyclic Aromatic Hydrocarbon Bioaccumulation in Pseudotolithus elongatus and Arius sp. from the Escravos River, Delta State

Abstract

Human activities such as petroleum mining within the Niger Delta have intensified contamination of aquatic ecosystems, raising concerns regarding the safety of fish consumed by humans. This study evaluated the concentrations of heavy metals and polycyclic aromatic hydrocarbons (PAHs) in Pseudotolithus elongatus and Arius sp. obtained from the Escravos River, Delta State, Nigeria, and assessed the associated human health risks among children, adults, and pregnant women. Dorsal muscle tissues were analysed using inductively coupled plasma mass spectrometry for heavy metals and gas chromatography mass spectrometry for PAHs, while data were analysed using descriptive statistics and one-way analysis of variance at p < 0.05. Arsenic recorded the highest concentrations in both fish species, with values of 8.263 ± 1.201 mg/kg in Pseudotolithus elongatus and 4.086 ± 0.840 mg/kg in Arius sp. Chromium was detected only in Pseudotolithus elongatus, whereas nickel occurred exclusively in Arius sp. Among the analysed PAHs, only phenanthrene, anthracene, and pyrene were detected at trace concentrations. Human health risk assessment using Estimated Daily Intake, Target Hazard Quotient, Hazard Index, and Carcinogenic Risk models revealed that arsenic exposure exceeded established safety thresholds across all population groups, particularly among children consuming Pseudotolithus elongatus (0.01598 mg/kg/day). Hazard Quotient and Hazard Index values exceeded unity, while carcinogenic risk values associated with arsenic surpassed acceptable regulatory limits. The findings identify arsenic as the major risk-driving contaminant and highlight the need for continuous biomonitoring and stricter pollution control within the Niger Delta aquatic environment.