Assessment of heavy metal pollution in sediment and biota from streams of Mtoni area in Dar es Salaam

No Thumbnail Available
Journal Title
Journal ISSN
Volume Title
University of Dar es Salaam
Heavy metals pollution in the sediments and associated biota from Mtoni area, Dar es Salaam was assessed. Physico-chemical parameters of waters from Kizinga, Mzinga, and Little Mzinga and Yombo streams were also recorded. Highest levels of turbidity (341.95#670.62ftu), electrical conductivity (1841.24#985.33uS/cm), pH (7.8#0.9) and temperature (31.60#3.20 oC) were observed in Kizinga stream waters. Sediments and oligochaetes samples were obtained from Kizinga and Mzinga streams whereas Uca crabs and polychaetes samples were obtained from Kizinga and Mzinga streams only. Samples were analyzed for Cu, Zn, Pb, and Cd using flame AAs and total Hg using a Semi automated Mercury Analyzer. The highest concentration of Cu (69.77#0.9) #58.01 ugg-1 dw) and Zn (323.67#92.8ng g-1 dw) were observed in the sediment samples from Kizinga stream whereas concentration of Pb (201.8#177.4 ug g-1), Cd (1, 44#0.34 ug g-1) and THg (677.1#92.8 ng g-1 dw) were higher in Yombo stream. Sediment samples from downstream of station 9 in Kizinga stream had higher concentration of cu and Zn compared to upstream stations. Station No 9 is in the Vicinity of a liquid oudrain pipe fall from KTM. It was observed that the area at the outfall of the drain pipe from Karibu Textile Mill (KTM) had higher concentrations obtained in other streams. More likely, it is due to the dyes and other chemicals used in the processing of fabrics at KTM. The study showed that oligochaete worms respond well to concentration of Pb, Zn and Cd in the sediments, therefore are potential bioindication of pollution by these metals. The higher concentration of Cu, Cd and Zn in Uca crabs and polychaeta worms from relatively polluted areas suggest that the crabs and worms concentrate this metal in the tissue. The study has shown that effluents from KTM pollute sediments in Kizinga stream with heavy metals. Therefore, it is recommended that the textile factory the encouraged to adopt cleaner production technology and execute a monitoring programme for stream.
Available in print form, East Africana Collection, Dr. Wilbert Chagula Library, Class mark (THS EAF QH545.A15H42H37)
Heavy metals, Pollution, River sedments
Hassan, M. (2008) Assessment of heavy metal pollution in sediment and biota from streams of Mtoni area in Dar es Salaam, Master dissertation, University of Dar es Salaam. Dar es Salaam.