Comparative evaluation of heavy metal contamination, nutritional quality, and associated health risks of selected imported and locally produced fish feeds in Ijebu-Ode, Ogun State, Nigeria

Abstract

The quality and safety of aquaculture feeds are essential for sustainable fish production and public health due to their nutritional and contaminant profiles. This study comparatively assessed proximate composition, heavy metal contamination, and associated health risks of imported floating and locally produced sinking fish feeds in Ijebu-Ode, Ogun State, Nigeria. Proximate analysis showed higher crude protein in sinking feeds (41.50–47.50%) than floating feeds (33.48–46.02%). Heavy metal concentrations in floating feeds ranged from BDL–0.15 mg/kg (Pb), 0.01–0.30 mg/kg (Cd), 10.50–25.00 mg/kg (Zn), and 16.00–25.00 mg/kg (Cu), while sinking feeds contained 0.10–1.30 mg/kg (Pb), 0.23–1.30 mg/kg (Cd), 17.00–40.00 mg/kg (Zn), and 9.82–20.42 mg/kg (Cu). Mean Pb (0.57 mg/kg) and Cd (0.50 mg/kg) in sinking feeds exceeded the WHO limit of 0.30 mg/kg. Health risk assessment showed higher exposure in sinking feeds. For children, THQ values reached 3.925 (Cu) in floating feeds and 1.243 (Pb), 3.840 (Cd), and 2.975 (Cu) in sinking feeds, indicating significant non-carcinogenic risk. The hazard index ranged from 1.224–1.979 for adults and 5.366–8.675 for children, indicating cumulative risk, especially among children. Carcinogenic risk (CR) for Cd ranged from 1.37×10-3 –5.34×10-3 (adults) and 6.02×10-3–2.34×10-2 (children), exceeding acceptable limits (10⁻⁶–10⁻⁴), suggesting possible long-term health effects. Relative risk values were highest for Pb (19.49) and Cd (3.89), suggesting higher exposure from sinking feeds. These findings highlight the need for stricter quality control of locally produced feeds to ensure aquaculture safety.