Fish (Arius heudelotii Valenciennes, 1840) as bioindicator of heavy metals in Douala Estuary of Cameroon

Abstract

This study assessed and monitored accumulation levels of heavy metals (Fe, Pb, Cu, Zn and Mn) in a prominent benthic mangrove fish species (Arius heudelotii Valenciennes, 1840) from the Douala Estuary, Cameroon. Fish species selection was based on signs of deterioration in taste and texture. Sampled estuarine water and tissue parts (liver, gut, flesh, gills and bones) of the captured fish were analyzed using atomic absorption spectrophotometer. The results show that concentration of the heavy metals except Mn in water was below the permissible limits imposed by WHO and USEPA for aquatic life. The metal levels in fish collected were significantly higher (p<0.05) than the levels in water, indicating bioaccumulation. Metal levels in the fish organs varied considerably with the highest mean concentrations of Pb and Zn found in the flesh and gills. The high concentration of heavy metals in these parts makes the fish unsafe for consumption as the majority of consumers depend on these parts for their livelihood. This calls for environmental surveillance and monitoring of these water bodies and their surrounding environment.

Key words: Arius heudelotii, bioaccumulation, heavy metals, estuary, environmental surveillance.