ASSESSMENT OF HEAVY METAL CONTAMINATION IN FISH (PAPYROCRANUS AFER) FROM OVIA RIVER, EDO STATE, NIGERIA USING NON-INVASIVE TECHNIQUES

ABSTRACT

This study evaluated heavy metal (Zn, Pb, Fe, Cu and, Cd) contamination in Papyrocranus afer, from Ovia River in Edo State, Nigeria. The muscle tissue, scales, and caudal fins samples were analyzed using standard methods. The results revealed varying concentrations of these heavy metals across different fish tissues. The highest level of Fe (2.834mg/kg) was recorded in the caudal fin clips, while the lowest level of Fe (2.657mg/kg) was recorded in the muscles. For Zn , the highest level (0.584mg/kg) was recorded in the caudal fins, while the least level (0.043mg/kg) was recorded in the scales. The highest level of Cu (0.135mg/kg) was recorded in the caudal fins while the lowest value was recorded in (0.014mg/kg). No presence of Pb recorded in caudal fins, muscles and scales (below detectable levels). Cd (0.009mg/kg) had its highest level in muscle while the lowest level was recorded in both caudal fins and scales (below detectable levels). Importantly, the concentrations of heavy metals in each level were within the allowable thresholds according to the standards set by both the European Union and the World Health Organization. These findings suggest that non-invasive techniques such as scales and caudal fin clips could serve as viable alternatives to muscles tissue sampling for assessing heavy metal contamination in fish, thus reducing the need for lethal procedures in future studies.