Influence of anthropogenic activities on heavy metal distribution in urban environment: a case study of Kinondoni Municipality

The study was carried out in the City of Dar es Salaam within the Kinondoni Municipality on four sites of Mikocheni industrial area, Kigogo residential area, Bunju suburban area and university area along Sam Nujoma road in order to determine the level of heavy metals in plants, water and soil for possible influence from human activities. A group of 40 soil samples were taken on grid basis at density of 90sqm at Bunju and University and randomly at Mikocheni industrial area and Kigogo residential area, where they’re already built out structures that has to be taken into consideration during sampling. plants and water samples were taken from Bunju, University and Kigogo and none of these samples are available in Mikocheni. GIS- based mapping techniques was used to locate sampling points. Five heavy metals in soil (Pb, Cu, Zn & Cr) and six heavy metals (Pb, Fe, Cu, Zn, Cr & As) in plants and water were analysed by AAS. Topsoil in urban areas (Mikocheni, Kigogo and University) was found to have significantly higher concentrations of heavy metals compared to Bunju suburban area. Statistical analysis of dataset has highlighted the influence of anthropogenic activities on heavy metal content of topsoil and plants in urban areas. The higher concentrations was observed in Mikocheni industrial area and areas close to road side where concentrations decreases with increasing distance from road edge.