Acacia trees-legume potential for phytoremediation of urban landfill soil in Bonoua (Côte d’Ivoire).

Document Type : Research Paper


Unité de Formation et Recherche des Sciences de la Terre et des Ressources Minières, Laboratoire des Sciences du Sol, de l’Eau et des Géomatériaux, Université Felix Houphouët-Boigny, Abidjan


Landfills in urban areas contributes to the pollution of soil and water with heavy metals. In Côte d’Ivoire, urban landfills are used to produce food which present health risk. This study evaluates the growth capacity of Acacia spp. trees-legume (Acacia mangium, Acacia auriculiformis and Acacia crassicarpa) and their potential for landfill soil remediation and restorations. To reach this aim, these trees-legumes were grown under controlled conditions during six months on polluted soils sampled from urban landfill located in southeastern Côte d'Ivoire, according a simple completely randomized design with 4 treatments (Acacia mangium, Acacia auriculiformis and Acacia crassicarpa, and control), and five replicates. Growth parameters, soil pH, metal contents (bulk soil, leachate) and plants were measured during this experiment. Results indicate that Acacia auriculiformis and Acacia mangium displayed the better growth indicators (dry biomass, heights and number of phyllodes) compared to Acacia crassicarpa. The soil pH under tree-legumes indicated a significant decrease compared to control (p < 0.05). In addition, heavy metal contents significant decrease in leached solutions of planted soil compared to control (p < 0.05). In the exchangeable soil fraction, only the Acacia auriculiformis treatment shows a significant decrease in Zn compared to the control. Regarding plants, Acacia auriculiformis showed the highest amounts of Pb (111 µg plant-1) and Cd (54 µg plant-1) in total biomasses. Acacia crassicarpa had highest metal extraction capacity from polluted soil (Pb: 24 µg plant-1, Cr: 11 µg plant-1, Cd: 14 µg plant-1, and Zn: 83 µg plant-1) compared to the two other species. This species, Acacia crassicarpa, appears to be the best specie for the phytoremediation of landfill soils.


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