Variability in Levels of Heavy Metals in Water and Fish (Chrysichthys nigrodigitatus) tissues from Badagry Creek, Nigeria

摘要

The occurrence of metals viz., lead (Pb), zinc (Zn), copper (Cu), iron (Fe), cadmium (Cd) and chromium (Cr) in water and fish ( Chrysichthys nigrodigitatus ) samples collected bi-monthly from nine stations (water) and 3 designated landing sites (fish) of Badagry creek were investigated using atomic absorption spectrophotometer (AAS) method. With an exception of cadmium, metals concentration was lower in the water samples and higher in the fish tissues, indicating a bioaccumulation tendency of fish. Concentration levels in water were found in decreasing order of magnitude Cr & Pb & Fe & Zn & Cu & Cd. However, metals investigated except Cu (highest concentration in the liver) had highest concentrations in the fish gills, which could be related to the uptake pathway. The relatively lower wet season Cu, Pb, Cr and Cd in water could be attributed to a dilution effect of rainfall. Although, presently the mean concentrations of all the heavy metals except Pb in this study were moderate and within the Federal Environmental Protection Agency (FEPA) permissible standard limit for aquatic life , the elevation of metal concentrations in this creek is inevitable under the prevailing conditions of increasing urbanization, industrialization and other forms of modernization in Badagry and environs. Nevertheless, it is imperative to ensure regular monitoring of heavy metal loading in this creek and other water bodies with a view to safeguard public health.