Bioconcentration and kinetic of desorption of potentially toxic elements in soils cultivated with vegetables in organic and conventional systems

Abstract

Plants demand nutrients for their growth from soil solution. However, potentially toxic elements (PTEs) can be absorbed and accumulated in vegetables organ and tissues. This is an important channel through which PTEs can enter into the food chain. The study of the dynamics of elements in the soil is fundamental to a better understanding of factors that influence soil-plant transfer, keeping in mind that soil management may interfere in the behavior of the elements in the system. In the state of Pernambuco, Brazil, the production of vegetables is mainly concentrated in small or medium organic and conventional farms located in the Agreste and São Francisco regions. The intensive use of soil may produce conditions that lead to contamination. Thus, our aims in this research are: i) to determine the contents of PTEs in soil and in vegetables produced under conventional and organic systems in producing regions of Pernambuco; and ii) to investigate the forms, the sorption and the desorption of the elements and their transfer into the plants. Acid and weak salt extractions will be employed to obtain pseudototal, reactive and bioavailable fractions of the PTEs. Kinetic assays will be developed, and soil organic matrix will be studied in detail through laser-induced fluorescence spectroscopy and nuclear magnetic resonance.