Pollution studies on Nigerian rivers: Toxic heavy metal status of surface waters in Ibadan City

The levels of the heavy elements cadmium, copper, cobalt, iron, manganese, nickel, lead, and zinc in the major streams and man-made lakes in and around Ibadan City were determined at roughly two monthly intervals between August 1977 and February 1979. They were found to be in the ppb and sub-ppb level except for iron and manganese which were in the ppm range. To assess the quality of these waters with respect to heavy metal contamination, a comparison is made between our results, world averages for both freshwater and seawater, and international water quality standards for drinking water. All elements, except iron manganese, were well within the safety limits. The low level of industrialization in Ibadan has kept its streams and lakes relatively free from heavy metal contamination.