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|Title: ||Land Based Activities and Sources of Pollution to the Marine, Coastal and Associated Fresh Water Ecosystems in the Western Indian Ocean Region|
|Authors: ||Francis, J.|
|ASFA Terms: ||Marine pollution|
|Issue Date: ||2003|
|Abstract: ||The lack of infrastructure and treatment facilities for the large quantities of domestic sewage generated by expanding coastal urban populations, and an increasing number of visiting tourists, represents the greatest threat to public health, coastal habitats and economic development in each state of the region. Other priorities requiring action include the effects of siltation related to agricultural activity and the dumping of solid domestic waste in the coastal areas leading to the degradation of coastal habitats, with implications for fish stocks and catches. Furthermore, laws and policies regardinng waste disposal and quality of effluents need to be enacted and reinforced Although eutrophication and algal blooms associated with agricultural, industrial or domestic sewage pollution have been identified as a threat to coastal habitats, further scientific research is required to link the causes and effects. Monitoring programmes need to be initiated in the region in order to mitigate pollution.
Agriculture is the backbone of the economy of most countries in the region. In 1982, 90% of the population in the region depended on agriculture. With the exception of Mauritius, the physical effects of siltation resulting from agricultural activities are currently of greater concern throughout the region than agrochemical pollution. There is insufficient evidence to indicate whether pesticide pollution in the more intensively farmed coastal areas of the region poses a significant threat to potable water supplies, or to coastal habitats receiving elevated nutrients loads in agricultural run-off. The trend in increased use of both fertilisers and pesticides in intensive agricultural production is likely to lead to elevated concentrations of chemicals in agricultural runoff and ground waters.
Overall, industrial development in the region remains relatively low. Industrial activities are focused at the ports and harbours of both the mainland and island states. The number and type of manufacturing industries have changed considerably since 1982. Few industries in the region have waste treatment plants and/or recycling facilities. Many industries empty effluents directly into creeks and rivers leading to the sea or directly to coastal waters. Furthermore, toxic wastes have recently started appearing among wastes disposed.
There is a direct relationship between population growth and waste generation. In the case of most large urban centres the solid waste and sewerage facilities have remained the same while the population has increased leading to decline in percentage population served by the facilities. Only a small proportion of dwellings throughout many of the large urban centres of the mainland states are connected to a sewage system. Even then the sewage collected is often pumped directly into coastal waters without any treatment. Rapid urban population growth in the coastal towns have lead to rapid changes in land use patterns. Natural ecosystems are being disturbed or replaced by agricultural crops. The large coastal population is also putting pressure on the marine and coastal resources. Lack of infrastructure and treatment facilities for the large quantities of domestic sewage generated by expanding coastal urban populations, and an increasing number of visiting tourists, represent a great threat to public health, coastal habitats and economic development in the region. Although monitoring data are not available, there is a perceived link between domestic sewage and the occurrence of water borne diseases in most of the coastal townships in the region. There is an urgent need for monitoring of microbial contamination of ground waters in coastal areas of all states of the region.
This paper provides an inventory of land-based activities and sources of marine pollution to the marine coastal and associated fresh water environment. It further oversees future developments and suggests priorities for action to mitigate the problems.|
|Description: ||Intitute of Marine Sciences, University of Dar es Salaam, Tanzania, series report.|
|Appears in Collections:||Articles (IMS)|
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