Contribution of Sewer Discharge and River Msimbazi on Heavy Metals Loading in the Indian Ocean along the Dar Es Salaam Coast, Tanzania

The concentrations of heavy metals, lead (Pb), Zinc (Zn) and Cadmium (Cd) were studied in water and sediments at Ocean Road and Kigamboni sites at Dar es Salaam Coastal area. The project aimed to assess the contribution of the sewer pipe and Msimbazi River to heavy metals loading in the Indian Ocean. Samples were collected from the Ocean Road and Kigamboni stations, standard procedures for sample extraction were employed, sediments were prepared by wet digestion and metals were determined by atomic absorption spectrophotometer (AAS). Higher levels of lead (Pb) and zinc (Zn) were found at Ocean road compared to Kigamboni, suggesting possible contribution of the sewer pipe and the River Msimbazi. The concentrations of lead (Pb) and zinc (Zn) were found to be higher in sediment than in water for the two stations. Mean levels of the metals in water were 0.371mg/L (at Kigamboni) and 1.037mg/L (at Ocean Road) for lead while zinc and cadmium in water were below the method detection limit (MDL) at the two sites. Further study is recommended to study the actual load contributed by the River Msimbazi and the sewer pipe by taking into account the variation of physical parameters between the two sites.