Assessment of Heavy Metal in Urbanized Tropical River in Ibadan, Nigeria

Contamination by heavy metals in river water is a global problem especially in developing countries like Nigeria. Ten heavy metals were investigated in River Ona located in Ibadan, a state capital in Nigeria. The river which stretches over more than 30km length drains through different land uses in the city. Laboratory analysis conducted on ten water samples collected at 1km equidistance position reveals that concentration levels of six (Lead, Cobalt, Copper, Zinc, Manganese and Iron) out of the ten heavy metal investigated in the study conform to the World Health Organization (2011) recommendation for human consumption while the remaining for elements (Cadmium, Chromium, Nickel and Arsenic) were above the WHO (2011) recommended levels. The mere presence of heavy metals in concentration near those limits considered safe for human consumption should be a matter of concern especially for residents who use the river water for domestic activities and those who consume fish from the river. A number of recommendations were subsequently put forward as a way of quality management of the river water.