Assessment Of Heavy Metal Migration Through River Nyamwamba And Pollution Of Lake George Ramsar Site

The main aim of this study was to investigate the migration of heavy metals from Kilembe mine tailings along river Nyamwamba down to Lake George Ramsar site.This river passes through the old Kilembe copper mines and mine tailings dams on its course to Lake George Ramsar site.Water, sediments and plant samples were collected from seven different locations along river Nyamwamba. The samples were taken to the Laboratory for chemical analysis. Total concentrations of six heavy metals namely,copper, lead, cadmium, cobalt, iron and chromium for sediments, water, soil and the plant(Phragmites mauritianus) were determined. The p H and conductivity of water,soil and sediments were also determined in addition to the organic matter content of the soil and sediments. The average concentrations of heavy metals in water column were lower than in the sediments. The average concentrations of heavy metals in water and sediments increased down the gradient towards river Nyamwamba entrance into Lake George. In Phragmites mauritianus, the average heavy metal concentrations ranges were; Cu=11.3-23 mg/kg, Fe=0.453-1.486 mg/kg, Cd=0.1 mg/kg, Pb=1-3mg/kg, Cr=1.2-8.5 mg/kg and Co=1.9-6.8 mg/kg. On average the concentrations of all the heavy metals increased towards river Nyamwamba entrance into Lake George.The p H of sediments and soil were weakly acidic and that of water was weakly alkaline. The p H values ranged as follows; sediments 4.16 – 6.63, soil 6.29- 6.63,water 6.73- 7.91.On average, water showed higher p H values than those for soil and sediments. On the other hand, the ranges in the values of conductivity for sediments,soil and water were 16.5-498 ?S/ cm, 38.2-81.7 ?S/ cm and 38.5- 279 ?S/ cm respectively. Sediments showed higher conductivity values compared to water and soil.The conductivity values for both water and sediments increased down the gradient towards river Nyamwamba entrance(NE) into Lake George.Organic matter contents ranged from 2.376 g/kg to 234.298 g/kg in the sediments. The concentrations increased down the gradient towards river Nyamwamba entrance into Lake George. All in all there is migration of heavy metals from Kilembe Mines through river Nyamwamba and accumulation in river Nyamwamba entrance into Lake George.