Heavy metal content of surface water and crab (Potamon fluviatile) from the New Calabar River, Rivers State, Nigeria


  • J. D. Nwineewii
  • O. S. Edori
  • A. C. Marcus


Water and crab samples obtained from four different locations (Elibrada, Aluu, Choba and Iwofe) along the New Calabar River were examined for heavy metal content using atomic absorption spectrophotomer (AAS). The concentration of heavy metals in the water samples were in the order Ni > Cu > Fe > Pb > Cr > Cd > As > Zn. In the crab, the order was Fe> Zn > Cr > Cu > Ni > Pb > Cd > As. In all the metallic parameters examined in the water, the highest value for each metal was either obtained at the Choba or Iwofe station. In the case of the crab, the highest value of each metal was observed at either Choba or Iwofe station except for Fe and Cu where the highest values were obtained at the Elibrada station and followed by Aluu station. Contamination index assessment indicated that the river is extremely or excessively polluted with Ni and Pb at Elibrada, Choba and Iwofe stations, As at Choba station and Cr at Choba and Iwofe stations and a very severe pollution with Ni at Aluu station. Pollution index and contamination degree evaluation showed that the river is at varying degrees of contamination or pollution. Bioconcentration factor analysis showed that the crab is a bioaccumulator of all the metals examined except Cd. The results indicated a river that is under threat, therefore adequate measure should be put in place to check further input of heavy metal pollutants. Keywords: Heavy metal, Potamon fluviatile, environment, Pollution, New Calabar River