Bioaccumulation of chromium, copper, maganese, nickel and lead in a freshwater cichlid, hemichromis fasciatus from Ogba River in Benin City, Nigeria

Abstract

This study assessed and monitored the extent of Cr, Cu, Mn, Ni and Pb bioaccumulation by the freshwater fish (Hemichromis fasciatus) from Ogba River in Benin City, Nigeria between November, 2004 and October, 2005. The effects of Dry and Rainy seasons on the extent of bioaccumulation were specifically addressed. The results showed metals bioaccumulation levels differences (except Mn) at the sample stations, which were attributed to the influence of drainage effluents influx into the river. Seasonal levels of the metals were also different at the stations. Higher dry season levels were ascribed to higher water temperatures, while rainy season high levels, could result from pronounced leaching of metals. The finding that some metal accumulation levels exceeded WHO and PEPA recommended limits in food fish, indicated that the fish of Ogba River, might not be fit for human consumption. Consequently, close monitoring of metal pollution of Ogba River is strongly recommended.