Environmental health impacts of dispersed mineralisation in South Africa

The crust of South Africa has undergone various episodes and styles of mineralisation dating as far back as the Archaean The suite of minerals produced is diverse and includes metals non-metals and industrial minerals Since the Pleistocene substantial quantities of elements both nutritional and toxic that were involved in ore forming processes have been remobilised and redistributed by surficial processes of intense tropical weathering leaching eluviation podsolisation and gleying and more recently by mining and related processes as well as by other urban and industrial activities As a result of this dispersion it is not uncommon to find large tracts of the country containing anomalous trace element contents or deficiencies in essential micro nutrient elements Through water and food crops extremes in trace element variation in soils are transmitted into the food chain with often undesirable consequences for human and animal health But the known variations are not as yet adequately documented Nor is there sufficient knowledge on the implications of these variations for the health of the environment and its ecosystems Nutrient deficient soils may be the principal causative factor in the devastating endemic osteo arthritic disease that afflicts two-thirds of the women in Maputaland for instance The generally low Se status of agricultural soils could represent an important co-factor in the relatively high diffusion rates of HIV-AIDS in the country The impact of geology on animal health also remains an area of critical concern to both farmers and managers of the hugely important wildlife game reserves This paper discusses a few known relationships between trace element excess/deficiency stemming originally from mineralisation processes and the local and regional distribution of diseases in man and animals in South Africa It is submitted that the challenge for future research in medical geology would lie in an organised effort aimed at detecting verifying and documenting such relationships This would help greatly in broadening the diagnostic spectrum and therapy for a number of environmental diseases in the country (C)2010 Elsevier Ltd All rights reserved