Heavy metal concentrations in soils and leachetes of Mtoni dumpsite bordering the Indian Ocean in Dar es Salaam, Tanzania

Concentrations of heavy metals in soils and leachetes in the closed coastal dumpsite of Mtoni, Dar es Salaam, Tanzania were determined using Atomic Absorption Spectrophotometer. Mean concentrations of leachetes in mg/L were in the following order: Cr > Ni> Pb> As> Cd whereas, concentrations of As and Cr in the soil samples were above the established contaminant limits of Tanzania Standard Soil Quality. The concentration of Ni was low. Soil samples at 10 m from the edge of the dumpsite showed higher concentrations of Cd and Pb compared to the established national contamination limit. Based on this observation we recommend awareness creation to farmers depending on the area for vegetable production on the need to relocate their activities to at least 200 m away from the edge of the dumpsite. Moreover, alternative income generating activities for farmers should be considered by the communities and the municipal authorities in order to reduce health hazards that may affect urban smallholder farmers depending on the dumpsite areas for agricultural production.