The Potential for Employing Epidermal Mucus, Fish Scale, and Caudal Fin clip Samples as Non-Lethal Methods for Assessing Heavy Metal Contamination in Fish (Tilapia mariae (Boulenger, 1899) and Papyrocranus afer (Gunther, 1968) from Ikpoba River, Edo State, Nigeria

ABSTRACT

Heavy metals are considered potent and persistent pollutants due to their widespread presence, limited breakdown in biological processes, and harmful effects. They have the ability to accumulate and increase in concentration within biological organisms, posing significant toxicity risks especially in fish. Heavy metal accumulation in fish is crucial due to their importance as a protein source for many river-dwelling communities. Using Atomic Absorption Spectrophotometers, heavy metals were quantified after sample digestion according to standard methods heavy metal concentrations in the fish tissues was in the order: muscle > scale > fin in Tilapia mariae and fin > epidermal mucus > muscle in Papyrocranus afer. A strong positive correlation was observed between concentration of heavy metals in the muscle tissues and the other tissues (epidermal mucus, scales and caudal fin clips suggesting that the use of epidermal mucus, scales and caudal fin clips as alternatives to muscle tissues in accessing the concentration of heavy metals in the fish species (Tilapia mariae and Papyrocranus afer). Results showed that muscle tissue consistently exhibited the highest heavy metal concentrations, particularly iron (Fe), though concentrations did not significantly differ among tissues (p > 0.05). The findings of this study therefore contributes to understanding the distribution of heavy metals in fish tissues and highlights the value of non-invasive approaches in monitoring heavy metals in aquatic ecosystems.