Avaliação do potencial de bioacumulação de cromo em plantas de girassol

Plant-based remediation (phyto-remediation) is a biotechnological tool used for the decontamination of polluted soils and water bodies, even by metals. Bioaccumulation in sunflower (Helianthus annus L.) grown in soil contaminated by metallic chromium (Cr) is studied. The sunflower is one of the best hyperaccumulators for phyto-remediation sites polluted by metals. The accumulation of Cr in shoot biomass content and oil extracted from seeds of plants grown in soil contaminated by the metal were analyzed. The sunflower plants were grown in pots and treatments comprised potassium dichromate solutions (K2Cr2O7) at concentrations 0, 18, 36 and 72 mg kg-1, whilst analyses were performed by atomic absorption spectrometry. Results showed that there was a significant reduction in plant biomass of plants in proportion to Cr dose, accumulating high percentages of metal in shoot plant tissues. It was toxic at the highest concentration (72 mg kg-1), whereas metal rates were the same at different concentrations of Cr in the soil, in oil. Sunflower plants have a Cr phytoextractor potential when cultivated in soil contaminated by the metal. Oil extracted from the seeds grown under these conditions is not suitable for human consumption due to its high metal content rates.