Assessment of heavy metals in water, sediment and some fishes from a Tropical Creek, Southwestern, Nigeria

Abstract

The study was carried out in Abule Eledu Creek to assess bioaccumulation of metals in water, sediment and some fish samples. The fish samples: Sarotherodon melanotheron (black jaw tilapia), Periophthalmus koelreuteri (mudskippers) and Chrysichthys nigrodigitatus (silver catfish) were caught with gill nets following standard procedures. Water and sediment samples were also collected along the stretch of the Creek and analyzed for five heavy metals: zinc (Zn), Cadmium (Cd), lead (Pb), copper (Cu) and nickel (Ni) using the atomic absorption spectrophotometer. The results obtained from the study showed that metal concentrations decreased in the following order: Zn >Cd>Ni>Pb>Cu for mudskipper; Zn>Cu>Pb>Cd>Ni for tilapia and Zn>Cu>Pb>Cd>Ni for silver catfish in the sampling stations. While in water and sediment samples heavy metal decreased thus: Zn>Cu>Pb>Cd>Ni for water sample and Zn >Cd>Ni>Pb>Cu sediment sample. Among the heavy metals analyzed, zinc had the highest concentrations in all the tested samples. From the data presented, it could be concluded that the values recorded for these metals were found to be below the standard tolerable limits of for food fish. Thus, these fish specimen from Abule Eledu Creek could be considered wholesome for human consumption.