Metals Phytoextraction by Cordia africana from Soils Contaminated with Oil Drilling Waste

Abstract Oil exploration and production generate large quantities of waste, which may contain contaminants such as barium and lead. Therefore, more studies aimed at decreasing the levels of heavy metals in contaminated sites, using methods such as phytoremediation, are needed. In a preliminary assay, samples of soil contaminated with oil drilling waste were incubated with different concentrations (2 or 6 mmol L-1) of ethylenediaminetetraacetic acid (EDTA). Subsequently, an experiment was conducted in a greenhouse to evaluate the phytoremediation potential of the tree Cordia africana. EDTA induced mobilization and translocation of lead, manganese, and iron into the C. africana leaves but had no effect on barium. The quantity of heavy metal contaminants accumulated in the plant vegetative parts showed that C. africana cannot be used as a phytoextractor for the tested metals; however, it can be used as a phytostabilizer.