The use of heavy metals load as an indicator of the suitability of the water and fish of Ibiekuma Stream for domestic and consumption purposes

Abstract

The levels of Cd, Cr, Cu, Pb and Zn in the water and fish from Ibiekuma Stream, Ekpoma, Nigeria were determined at two locations (Upstream and Downstream) in order to ascertain their suitability for consumption and other domestic uses. Atomic Absorption Spectrophotometry was used to measure the metal levels. Seasonal (dry and wet seasons) levels were also determined. The results showed Zn mean levels were highest with 1.12 ± 0.51 mg/l in water and 45.5 ± 7.46 mg/kg in fish. Minimum levels were 0.005 ± 0.002 mg/l (Cd and Pb) in water and 0.70 ± 0.22 mg/kg (Cd) in fish. Pb was not detected in fish. Spatially, upstream location levels were generally higher than downstream levels for all the metals in both water and fish. Dry season levels were also generally higher for all samples and at both locations. The consumption of the fishes of the stream requires stringent precautionary measures
because of the high levels of Cr and Cu which exceeded limits in food fish and could therefore pose some health risks. It was also observed that all metal levels in water were within drinking water limits
and global background levels for surface fresh water. The implication of these findings is that the water of the stream could be used for drinking and other domestic purposes.