Abstract:
The treated wastewater from Pan-African Paper Mills (PPM) discharged into River Nzoia affects the concentrations of chemicals in the water, sediments and life forms of the river. In this study some of the chemical and physico-chemical, heavy and alkaline metals in the wastewater, river water, sediment materials and fish were determined. On the basis of their levels effects of wastewater on River Nzoia was assessed. The concentrations of Cd (08l ± 0.015 mgl,"), Cr (0.0:27 ± 0.024 rngl."), Cu (0.008 (0.53 ± 0.09 mgl.") and Zn (0.106 ± 0.045 mgl.") at EDP were higher than at WIP and EDP. The concentration of Ni (0.227 ± 0.036 mgl.") at WIP was higher than at both DSN and EDP, while the concentrations of Cu (0.008 ± 0.002 mgl."), Pb (0.419 ± 0.068 mgl.") and Zn (0.076 ± 0.012 mgl.") were higher at DSN than at WIP [Cu (0.003 ± 0.001 mgl."); Pb (0.413 ± 0.106 mgl."); and Zn (0.067 ± 0.015 mgL- 1)]. However the concentrations ofCr (0.010 ± 0.006 mgl.") and Ni (0.] 94 ± 0.064 mgl.") at DSN were lower than those at WfP (Cr, 0.0] 8 ± 0.009 mgl." and Ni, 0.227 ± 0.036 mgl."). ± <0.004 mgl."), Pb The concentrations of Ca (29. 27 ± 5.55 mgl."), K (9.62 ± 2.04 mgl."), Mg (2.13 ± 0.98 mgl.") and Na (248.48 ± 95.9t mgl.") at EDP were significantly higher than at both WIP and DSN. The concentrations of Ca (4.94 ± 0.76 mgl."), K (2.65 ± 0.32 gml."), Mg (0.47 ± 0.13 mgl.") and Na (19.06 ± 6.86 mgL- 1) at DSN v v 'ere higher than at WI? The levels of physico-chemical parameters at EDP were higher than at WIP and DSN except for dissolved O 2 which was not detected at EDP. The conductivity (325 ± 70 u Scm'), pH (8.38 ± 0.08) and temperature (20 ± 0.77° C) at DSN were significantly higher than at WIP. The levels of the total solids were higher at WIP than at DSN. The dissolved 0:-. level at DSN was 6.40 ± 0.45 mgl." compared to 7.26 ± 1.36 mgl." at WIP thus reflecting the impact of wastewater from PPM on River Nzoia. The concentrations of heavy solids at EDP were higher concentrations of heavy and higher than at WlP. Similarly, were higher than in gills offish and alkaline metals in the dissolved and suspended than at both WIP and DSN (Table 3.]). The alkaline metals in the sediments at DSN were also the concemrations of metals in gills of fish at DSN at WIP. Therefore the wastewater from PPM discharged into River Nzoia increased the concentrations of heavy and alkaline metals and the levels of the physico-chemical parameters in River Nzoia water. The wastewater also increased the concentrations of the heavy and alkaline metals in the sediments at DSN as shown by their Ig,:v (Table 4.4) and enrichment values (Fig. 4.14). The levels of heavy metals in fish from WIP and DSN show that the wastewater has contributed to the bioaccumulation
of heavy and alkaline metals in organisms in the river.
