African Journal of Biotechnology Vol. 6 (5), pp. 617-624, 5 March 2007   

ISSN 1684–5315 © 2007 Academic Journals        

Full Length Research Paper

Some physico-chemical characteristics and heavy metal profiles of Nigerian rivers, streams and waterways

Asonye, C. C.¹*, Okolie, N. P.², Okenwa, E. E¹ and Iwuanyanwu, U. G.¹

¹Department of Optometry, Faculty of Science, University of Benin, P.M.B. 1154, Benin City, Nigeria.

²Department of Biochemistry, Faculty of Science, University of Benin, P.M.B. 1154, Benin City, Nigeria.

*Corresponding author. E-mail: asonye@uniben.edu or caniceasonye@yahoo.com   Phone: 2348038117255.

Water samples of 72 rivers, streams and waterways in Southern Nigeria were carefully collected and the following physico-chemical analyses subjected on the samples.  Temperature, colour, taste, turbidity, pH, total dissolved solids (TDS), conductivity and heavy metal profiles (Pb, Cr, Cd, Fe, Zn, Mn, Cu) were assessed among the entire samples collected.  The turbidity (NTU) of 93% of all the samples was higher than World Health Organisation (WHO) and European Economic Community (EEC) standards. 57% of the entire samples had conductivities above normal limits. The pH of 81% of the entire samples also were above WHO and EEC guide limits. Profiles of the heavy metals showed Pb, Cd, Cr, Zn and Mn levels in some of the samples being above the guidelines of WHO and EEC. Fe had 55% of all the samples exceeding recommended standard of 0.20 ppm; Cr had 15% exceeding the recommended 0.05 ppm, Cd had 11% exceeding 0.003 ppm while 7% of both Zn and Pb exceeded 3 ppm and 0.10ppm respectively.  These results indicate that heavy metal pollution and toxicity might pose serious risks to the health of communities residing around and using these surface waters for domestic, commercial and socio-cultural purposes.

Key words: Water, physico-chemical characteristics, heavy metals, pollution, toxicity, health.