RISK ASSESSMENT OF HEAVY METALS AND POLYCYCLIC AROMATIC HYDROCARBONS IN AFRICAN RIVER PRAWN (MACROBRACHIUM VOLLENHOVENII) FROM FORCADOS RIVER IN BURUTU AND AYAKOROMO COMMUNITIES, DELTA STATE NIGERIA

This study evaluated the presence of heavy metals and polycyclic aromatic hydrocarbons (PAHs) in Macrobrachium vollenhovenii from the Burutu and Ayakoromo sections of the Forcados River, and assessed associated human health risks. Mean concentrations of heavy metals in Burutu prawns were highest for zinc (17.590 ± 3.431 mg/kg), copper (12.782 ± 2.185 mg/kg), strontium (2.997 ± 0.956 mg/kg), and cobalt (2.134 ± 0.672 mg/kg), exceeding the reference dose for copper (0.07 mg/kg/day), whereas most other metals, including arsenic, cadmium, chromium, lead, and selenium, were below detection limits. In Ayakoromo, metal concentrations were generally lower, with zinc at 8.879 ± 1.874 mg/kg and copper at 7.191 ± 1.653 mg/kg. PAH analysis showed elevated levels in Burutu prawns, particularly Benz[a]anthracene (0.0773 ± 0.0103 mg/kg), Benzo[b]fluoranthene (0.0244 ± 0.0074 mg/kg), Dibenz[a,h]anthracene (0.0178 ± 0.0000 mg/kg), and Benzo[a]pyrene (0.0153 ± 0.0023 mg/kg), while Ayakoromo prawns exhibited minimal PAH contamination. Estimated Daily Intake (EDI) revealed children in Burutu had the highest dietary exposure to zinc (17.590 mg/kg/day), copper (12.782 mg/kg/day), and PAHs such as Benz[a]anthracene (0.0773 mg/kg/day). Non-carcinogenic risk assessment showed Hazard Index (HI) values above 2700 for children in Burutu, indicating substantial potential health risk, whereas Ayakoromo HIs were below 103, suggesting lower risk. Carcinogenic risk analysis revealed negligible lifetime cancer risk from heavy metals at both sites, but Burutu prawns presented moderate PAH-related carcinogenic risk, especially for children. The findings indicate localized contamination in Burutu likely from industrial and oil-related activities, highlighting potential ecological and human health risks. Continuous monitoring, public awareness, and targeted mitigation strategies are recommended to reduce exposure and protect vulnerable populations.