Volume 9 October 2004
ISSN 1438-7890 |
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African
Journal of Environmental Assessment and Management
Revue africaine de gestion et d’évaluation environnementales |
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The
Magnitude and Spatial Distribution of In-use Zinc Stocks in Cape
Town, South Africa
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D. van Beers and T.E. Graedel
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| Cape Town is a major urban area that possesses
large reservoirs of in-use zinc. These reservoirs will gradually
become available for re-use as the zinc-containing products become
obsolete, should re-use prove technologically and economically
feasible. Hence, we have identified and quantified the principal
zinc uses in Cape Town and estimated their lifetime, using a model
incorporating Geographic Information System (GIS) software. We
estimated the in-use stock at approximately 57 Gg and predicted
end-of-life flows for several decades into the future. By 2030, we
anticipate an in-use zinc stock more than twice as high as currently
present. Our GIS analysis demonstrated that although the per capita
stock of in-use zinc is lowest for poor community areas, these areas
have higher spatial densities of zinc than wealthy areas because of
the very high housing and population densities. If all end-of-life
zinc is reprocessed, rather than discarded as waste or transferred
outside the region, it could supply up to 50% of Cape Town’s zinc
demand over the next three decades.
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