Heavy metal threats to plants and soil life in Southern Africa: present knowledge and consequences for ecological risk assessment

Abstract

In recent times there has been remarkable development in the field of soil ecotoxicology and risk assessment (RA) models. It is, however, debatable if these RA models are robust representatives for worldwide relevance. In order to investigate this, the current overview aims to address heavy metal threats to soil life in southern Africa by investigating present knowledge and consequences for RA using research in southern Africa as a case. To this end, the focus is on southern African soils, soil life and living conditions. To critically discuss these issues, we report on extensive research conducted in the southern African context and looked how comparable these findings are to RA models employed in the western world. This is done by providing an inventory of selected studies focused on the ecotoxicity of metals towards soil life. It is concluded that there is a dearth of information on southern African soil life, most of which are laboratory-based studies carried out by a handful of researchers. Future research incorporating the available information into a soil ecosystem assessment procedure is paramount. It is recommended that a starting point to tackle this might be the development of holistic sight-specific guidelines for ecological risk assessment at larger spatial scales (km2) which takes into cognizance landscapes, vegetation and faunal characteristics