Comparative assessment of potential toxic metals concentrations in water, sediment and fish (Clarias gariepinus) in Epe Lagoon, earthen and concrete ponds in Epe Area of Lagos State

Olowu Rasaq A, Osundiya Medina

Abstract

The level of some heavy metals , zinc (Zn), cadmium (Cd), copper (Cu), manganese (Mn) and iron (Fe)) in Clariasgariepinusfrom Epe lagoon, earthen and concrete ponds within Epe were investigated using Atomic Absorption Spectrophotometer (AAS) and the analysis of all the samples were done in triplicates. The results revealed the accumulation of metals differently in various parts of the fish namely the head, gills, trunk and tail. Cadmium (Cd) was detected in all the samples but below the permissible level which may be due to few industrial and domestic activities around the Epe axis and locations sampled. The order of accumulation of metals in C. gariepinus from both the lagoon and the ponds were Head>Tail>Gill>Trunk and the pattern of PTM distribution was Zn>Fe>Cd>Mn>Cu in all the organs. The concentration of cadmium in the fish sample obtained for lagoon was higher compared to a lower value of 0.166 and 0.114mg/L obtained for earthen and concrete ponds which may be attributed to discharge from anthropogenic activities, domestic and industrial wastes respectively. The mean values of PTM obtained in the fish parts were in the range: Fe (0.333±0.004 – 0.515±0.003mg/L); Zn (0.366±0.003 – 0.553±0.002mg/L); Cd (0.172±0.002 – 0.199±0.0mg/L); Mn (0.038±0.001 – 0.056±0.002mg/L), Fe (0.326±0.002 – 0.542±0.003mg/L); Zn (0.181± 0.001–0.692 ± 0.003 mg/L); Cd (0.166±0.003– 0.194±0.001 mg/L); Mn (0.011±0.01–0.050±0.003 mg/L) and: Fe (0.084±0.001–0.235±0.001 mg/L); Zn (0.306 ±0.003– 0.787±0.006 mg/L); Cd (0.114±0.001–0.207±0.001 mg/L); Mn (0.115±0.002–0.122±0.001 mg/L for Epe lagoon, earthen and concrete ponds respectively. The highest concentrations of iron (Fe) and zinc (Zn) was obtained in the fish parts from the earthen and concrete pond compared to that from the lagoon which may be attributed to the fact that these metals are naturally rich in Nigerian soils. It is noteworthy that concentrations of the metals in all the samples analyzed are lower than the permissible limits set by WHO and FEPA which implies that the fish are safe for human consumption.