Distribution and yield of trace metals from the foot of Mount
Kilimanjaro to the coastal of Indian Ocean: impacts of natural and
anthropogenic factors
- Juma Rajabu Selemani,
- Xunchi Zhu,
- Arafa Majjid,
- Jing Zhang
Abstract
Cases of water related diseases due to metal pollution are increasing
over the global. The condition is serious to most of developing
countries as a results of industrialization and population growth.
Dissolved and particulate trace elements influence drinking water,
aquatic ecosystem health and climate change. Mt. Kilimanjaro is one of
the sources of water and icon in Africa but miss studies on dissolved
and particulate metals. Therefore, this study was conducted to
investigate geochemistry, distribution and yield of dissolved and
particulate metals from Mt. Kilimanjaro to Indian Ocean. Surface water
was sampled in rainy season and analyzed by high resolution inductively
coupled plasma mass spectrometry in State Key Laboratory of Estuaries
and Coastal Research. Health assessment revealed that level of
Aluminium, iron, vanadium and Manganese in some stations were above
recommended level, that can pose health impact to human and aquatic
ecosystem. Correlation of Cobalt, Copper, Manganese and Vanadium with
dissolved silicate, sulphate, calcium and dissolved organic carbon
indicates that these elements were predominantly found in silicate,
sulphide, carbonate and organic bounds. Positive relation between
magnetic susceptibility with Copper and zinc reflects that magnetic
susceptibility can be used as indicator of Copper and Zinc pollution.
Rock weathering and anthropogenic activities were main sources of metals
whereas redox reactions, pH, temperature and dissolved organic carbon
were some of biogeochemical factors influencing level of metals. The
basin transported more elements in particulate than dissolved form.
Yield from Pangani River to Indian Ocean was lower than most of other
rivers in East Africa.