Assessment of heavy metal concentrations in the muscles of ten commercial fish species from Lagos lagoon, NigeriaAssessment of heavy metal concentrations in the muscles of ten commercial fish species from Lagos lagoon, Nigeria

Abstract

The study was undertaken to assess the concentration of five heavy metals (zinc (Zn), lead (Pb), copper (Cu), iron (Fe) and manganese (Mn)) in the muscles of Tilapia zilli, Hydrocynus fiscalis, Parapristipoma humile, Caranx hippo, Cynoglossusa caudatus, Chrysichthys nigrodigitatus, Letjanus sp, Portunus validus, Sardinella maderensis, and Sphyreana sp. The concentrations of heavy metals were measured by atomic absorption spectrophotometry after digestion of the samples. There were significant differences (P<0.05) in the concentration of heavy metals in fish muscles. There was no specific pattern in the levels of heavy metals among the fish species. P. validus had the highest concentration of Zinc in the fish sampled with a mean value of 14.45mg/g while T. zilli had the lowest concentrations of Zn and Mn. Sphyreana sp had the highest concentrations of Lead and Copper and Manganese in the muscles. Iron concentration was highest in the muscle of S. maderensis. In this study, the overall average concentrations of metals in fish muscles were in the order of Zn> Fe > Pb> Cu> Mn. The values of Zn and Cu were within or lower than the acceptable limits FAO/WHO (Food and Agriculture Organization Of the United Nations/World Health Organization) for concentration of heavy metals in fish while levels of Pb, Fe and Mn in the muscles of the various fishes were beyond the safe limit in foods. Close monitoring of heavy metal pollution of Lagos Lagoon is strongly advocated, in view of possible risks to the health of consumers.