Cadmium phytoremediation using tropical ornamental species in amazonian soils

Abstract

Cadmium (Cd) contamination in tropical soils is a serious environmental problem, especially in fragile ecosystems such as the Amazon, where sustainable remediation strategies are urgently needed. This study investigated the phytoremediation capacity of three tropical ornamental species (Heliconia psittacorum, Canna indica, and Anthurium andraeanum) under semi-controlled experimental conditions with four Cd concentrations (0, 0.5, 1.0, and 2.2 mg.kg⁻¹). Bioaccumulation was evaluated using bioconcentration factors (BCF) and translocation factors (TF). Metal concentrations in roots, stems, and leaves were determined via atomic absorption spectrophotometry (iCE3500, Thermo Scientific). The results showed that Anthurium andraeanum was the species most affected by Cd exposure, with 100 % plant mortality in all treatments used (high, medium, and low), indicating high sensitivity. Meanwhile, Heliconia psittacorum accumulated the highest amount of Cd in the root system and exhibited low translocation (TF = 0.21). Canna indica transferred a greater amount of Cd to the aerial tissues (TF = 3.43) at medium experimental concentrations (1 mg.kg⁻¹), outperforming the results obtained in the low and high experimental treatments, which suggests potential for phytoremediation of the metal at moderate concentrations. Significant differences (p < 0.05) were observed in Cd accumulation across the phytoremediation indices. There was no variability in soil pH (neutral to slightly acid). These findings suggest different responses among species that have complementary effects and would support the integration of ornamental plants into sustainable strategies for the remediation of tropical soils contaminated with cadmium.