The remediation of metal(loid) polluted soil using plants (i.e. phytoremediation) often requires the application of amendments, as well as chemical fertilizer. However, such fertilizers can have negative effects when applied alone and can thus be applied together with other organic amendments to diminish this negative effect. Finally, plants to be used in phytoremediation should be selected based on their adaptive capacity and tolerance to poor and highly contaminated soils, characteristics that possessesAilanthus altissima. The objective of this study was to evaluate the effects of osmocote fertilization on the amended mining technosol properties and plant growth parameters, as well as to study the accumulation pattern of As and Pb in plant roots. Results showed that osmocote ameliorated soil conditions, but increased Pb mobility. It also greatly improved plant growth. Finally, different behaviours of metal(loid) accumulation were observed in the roots: As was absorbed mainly in the roots because of its similarity with P, with very low amounts in the leaves, whereas Pb was adsorbed mainly on the root surface, with lesser proportion absorbed inside the root system.