Abstract

  Concentration levels and distribution of Pb, Zn, Cu, Cd, Fe, Cr and Mn were determined in water and sediments during a monthly monitoring of rivers feeding Lake Victoria (Kenya). Results of metal contents in the <63um sediment fraction, determined using atomic absorption spectrophotometer (A.A.S), showed high contents of Mn, Zn, Cr and Fe as compared to background levels and unpolluted sediments. The surface water Zn, Cr and Pb contents revealed significant (p < 0.05) temporal variations, with high physical pollutants and elevated Fe, Mn and Al contents. This was a reflection of the high load of land based materials transport in the surface waters. Impact of urban and non-point derived wastes was evident in rivers within these zones, especially those acting as recipients and dilutants of various waste discharges, due to their low and highly variable water volume. Three distinct groups of rivers were obtained from cluster analysis using all variables determined.