Heavy Metals in organs and endoparasites of Oreochromisniloticus , Sediment and Water from River Ogun , Ogun State , Nigeria

Endoparasites have the ability to accumulate heavy metals and the capacity to detect even the lowest heavy metal concentrations. These have made them more suitable water pollution biomonitors than their fish hosts. Therefore, ninety Nile Tilapia, (Oreochromisniloticus), collected at 3 different points along River Ogun at Abeokuta were examined for presence of endoparasites. Fish muscle and organs, endoparasites, water and sediments samples collected at three sites were analysed for levels of Zn, Cu, Cd and Pb. Four trematodes species: Allocreadiumghanensis, Phagicola longa, Clinostomumtilapiae, and Dipylidiumcaninum and one acanthocephalan, Acanthogyrustilapiae were identified from the fishes. There were variations in the heavy metal levels in sediment, water, fish tissues and parasites. The highest level of heavy metal accumulation was recorded in the parasites compared to fish tissues. Bioaccumulation levels of Pb, Cd and Cu were in the order: Parasites>Fish Muscle> Liver > Intestine. The highest concentrations of Cd (0.67±0.21), Pb (2.89±1.25) and Cu (4.16±1.04) were recorded in parasites while Zn (14.27±4.32) levels were highest in the liver. The higher heavy metal levels in endoparasites indicate the potential risks of metal accumulation from fish consumption and suggest parasite suitability as bioindicators of heavy-metal pollution in aquatic ecosystems.