Trace Metals in Black River Sediments, Western Cape, South Africa

The increase in urbanisation and the use of metal compounds and products domestically and in industry has resulted in the production of by-products and wastes, which needs to be evaluated in the urban environment. The discharge of some of these wastes into urban rivers should be evaluated to determine the potential effects, for example, toxicity and mobility. The effects may, in part, be determined by the chemical states in which these wastes manifest themselves, and by the chemical associations they have. The sequential extraction technique of Tessier et al. (1979) was applied to the Black River and the Raapenberg riparian wetland sediments under nitrogen atmosphere, with a good level of accuracy, in order to evaluate the levels of metal pollution in the Cape Metropolitan area, South Africa.