Journal d'écosystème et d'écographie

Abstrait

Bioconcentration of Trace Metals in the Freshwater Snail Melanoides tuberculata (Mollusca: Thiaridae) from Alaro Stream Ecosystem of South West Nigeria

Emmanuel Teryila Tyokumbur and Tonye Grace Okorie

The level and tissue bioconcentration of V, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Ag, Cd and Pb were determined in the viscera and shell of the freshwater snail, Melanoides tuberculata in the upstream and downstream of Alaro stream, South West Nigeria. Trace metal concentrations in snail and sediment samples collected from six stations were measured using an Inductively Coupled Plasma-Mass Spectrometry (ICP-MS).

The mean trace metal concentrations (ppm) of V, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Ag, Cd and Pb in the snail were estimated to be 2.10-3.26, 28.31-33.32, 1668.21-2398.43, 1.75-3.98, 6.18-8.12, 33.86-89.23, 12.10- 66.35, 0.78-0.96, 9.86-11.35, 1.44-1.73, 1.98-2.33, 2.88-3.22 and 10.12-14.12 respectively. The study shows that M. tuberculata is capable of bioconcentrating trace metals in magnified quantity than that found in the sediment. The tissue concentration pattern was correlated with the amount of trace metals in the sediments. Bioconcentration of the trace metals V, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Ag, Cd and Pb varied between the viscera and the shell with the viscera having the highest concentration of all the trace metals. Results of the study indicate that ingestion of sediments and algae may be the main uptake route of the trace metals in Melanoides tuberculata.