TRACE METALS IN WATER FROM OLOGE LAGOON, LAGOS, NIGERIA
The concentrations of Fe, Mn, Cu, Zn, Cd, Pb, and Ni were determined in water of Ologe lagoon on a bimonthly intervals between January 1997 and December 1998. The recorded heavy metal concentrations (except iron) were either significantly lower or within the safety limits of published averages for freshwaters; recommended standards by the EC, Canada, and USSR for the use of fisheries and aquatic life. A higher concentration of Fe reflects the natural sources due to the geology of the catchment soil. Variations in the concentrations of heavy metals in water may be due to local differences in current velocity and distance from the shore line (from sewage source of the residential sector). The level of industrialisation in the study area is very low; hence, contribution of heavy metals from industrial sources on the heavy metal status of the lagoon is minimal.