Diversity of the edible fishes of the Lagos Lagoon, Nigeria and the public health concerns based on their Lead (Pb) content

Abstract

In this study, a total of eighteen fish species were recorded in the Lagos Lagoon, Nigeria during a one year
survey. Among the animals species recorded, the following, Galeoides decadactylus, Dentex gibbosus, Elops
lacerta, Scomber japonicus, Ethmalosa fimbriata, Lutjanus agennes, Caranx senegallus, Callinectes amnicola,
Paeneus notialis and Mytilus edulis were considered to be abundant in the Lagos lagoon based on the
frequency of occurrence in fishermen catches. The analysis of the lead content in muscles of the edible
fisheries revealed that the animals accumulated measurable quantity of lead in the edible parts. The level of
lead detected in most (12 out of 18 species) of the fisheries species were found to be lower than the daily
allowable concentration of 2.0 µg/g standard recommended by the World Health Organisation (WHO). Fishes
species with high level of lead in their edible parts include Senegal jack, C. senegallus (2.188 µg/g), Bobo
croaker, Pseudotolithus elongatus (2.024 µg/g), Cassava croaker, Pseudotolithus senegalensis (3.157 µg/g),
crayfish, Penaeus notialis (25.46µg/g), edible mussel, Mytilus edulis (17.69 µg/g) and crab, Callinectes
amnicola (10.19 µg/g). The mean levels of lead in Mytilus edulis, Penaeus notialis, and Callinectes amnicola
collected from the Lagos lagoon were about 8 to 24 times higher than the WHO daily allowable standards for
lead in sea foods and are therefore unsafe for human consumption. The need for regular monitoring of the
levels of metals and other contaminants in edible fisheries resources and collaboration between
environmental, health and food agencies to avert human tragedies due to lead accumulation are discussed.