Phytoremediation potential of Khaya ivorensis and Cedrela fissilis in copper contaminated soil.

Mineral exploration of copper (Cu) in the Amazon has significantly impacted the environment, leading to contamination of large areas that require remediation. Tropical tree species that can immobilize metals and restore plant cover should be selected for phytoremediation programs. The phytoremediation behavior of Khaya ivorensis and Cedrela fissilis was studied in Cu contaminated soil (60, 200, 400, and 600 mg kg-1). K. ivorensis absorbed extremely high amounts of Cu in the roots (329 mg kg-1) and excessive amounts in the shoot (52 mg kg-1), while maintaining similar growth to control plants. C. fissilis seedlings presented a higher Dickson quality index. Bioaccumulation (BCF) and translocation (TF) factors were low in both species, indicating that even with the high amounts of copper absorbed, these contents were lower than the soil concentration (BCF < 1) and that most of Cu was compartmentalized in the roots (TF < 1). The tolerance index of K. ivorensis (>1) and C. fissilis (~1) indicate their ability to grow in Cu contaminated soil. These results suggest that these species could potentially be used as phytoremediators.

Soil potentially toxic element contents in an area under different land uses in the Brazilian Amazon.

Soil pollution with potentially toxic elements (PTE) from incipient basic sanitation, dumps and industrial activities developed in the Amazon has been of international interest due to health and environmental issues. This study aimed to evaluate the concentration of PTE in five adjacent land occupations (a dump, a alumina refinery area and three residential centers) in the municipality of Barcarena, Amazon Region, Brazil. In a total area of 912 ha, 274 soil samples were collected at a depth of 0-0.2 m. Afterwards, the concentrations of As, Ba, Pb, Co, Cu, Cr, Hg, Ni and Zn were determined. The results were explored using descriptive and multivariate statistics, as well as geostatistical. Considering the data by location, maximum concentrations exceeding the prevention values of Brazilian soils were found for Cu, Ni and Zn in Dump (148; 42.8 and 356 mg kg-1), for Cu and Hg in Bom Futuro (333 and 1.99 mg kg-1) and for Cu in Itupanema (91.2 mg kg-1). Cu, Hg, Pb and Zn were grouped in the same principal component and showed the highest similarity measure in the cluster analysis. The interpolation point maps of the two principal components and of the individual concentrations of the PTEs showed the area of influence of the dump as the main reason for the increase in soil contamination. These results show the need for public policies aimed at the proper disposal of solid waste, in order to promote the reduction of pollutants in the soil, health and well-being for the local population, and also the environmental quality of the study area.