Potencial fitorremediador de Ricinus communis L.(Mamona) em solo contaminado pela presença de ferro (Fe²⁺), oriundo de rejeito de minério, em Minas do Camaquã - RS

Abstract

Anthropogenic activities such as those directed to mining, have contributed to the contamination of soil, water and ecosystems. The non-development of plant cover in extensive affected areas by reject of mined areas, can lead to extreme cases of environmental degradation. For recovery of degraded areas, the removal of a toxic agent in the soil, such as heavy metals, is usual and the use of phytoremediation techniques. This technique is the use of plant species that affect contaminants, such as phytoextraction and phytostabilization. Thus, this work aimed at the adjustment potential of the Ricinus communis L. (Castor) species, ex situ, in soil contaminated by ore tailings, with high levels of Fe2O3 (iron oxide), located in Minas do Camaquã, district of Caçapava do Sul, RS. For this purpose, growth parameters (height, stem diameter, main root size, number of leaves and secondary roots), physiological and morphological changes (changes in coloration and growth), and phytoextraction potential of Ricinus communis cultivated in different soils in 90 days of growth. As well as the concentrations of iron in the different soils used (control soil, collected at three different points of the study area, and soils with proportional mixtures of soil control and soil of the contaminated area). A variation of Fe concentration in the different soils was observed, with C being the highest concentration (0.0315 mg kg 1). The plants of Ricinus communis L. submitted to soils contaminated with tailings did not exhibit typical toxicity symptoms of Fe. In the growth parameters, we observed that P2 obtained higher height in relation to the other plant samples with height of 24, 7 cm. In addition, the species showed a bioconcentration capacity of Fe (P2 = 1.89 mg kg-1) and kept it in a higher concentration (P3 = 0.89 mg kg -1) using the phytostabilization technique. Ricinus communis has shown to be promising as a phytoremediate, and further studies have to be done (in the tailing area as well as in the long term) for a better understanding of the use of the species in this area.