In Katanga (D.R. Congo), a long history of mining activities has contaminated soils with heavy metals over very large areas. This represents a major concern to sustainable development and human health. Ecological restoration of those areas is challenging. The speech will present the results of a cooperation development project with the Faculty of Agronomic Sciences of the University of Lubumbashi, focused on the restoration of soil polluted by the metallurgical industry. The most original ecosystems in Katanga are the so-called "copper hills" i.e. natural outcrops of bedrock enriched in copper and cobalt. The natural vegetation of copper hills is surprisingly rich and diversified. The project developed applied ecological research in copper hills and ex situ i.e. in a botanic garden created for the occasion. A number of “metallophytes” have been screened for heavy metal tolerance and accumulation and for other traits of interest. One species has emerged as a good candidate and has been successfully domesticated in the botanic garden. The first in situ “phytostabilisation” trials have been installed in the area contaminated by atmospheric fallout downwind the copper smelter of Lubumbashi. Establishment, growth and survival have been monitored for 5 years. The results show that Katangan metallophytes exhibit extraordinary ecophysiological properties which are still poorly understood. They represent unique biological resources to ecological restoration of metal-polluted soils in tropical regions. The conservation of those resources must be explicitly considered in ongoing and future mining projects in Katanga.
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