Abstract
Spatial distribution of mercury and gold in roots of cassava (Manihot esculenta) by micro-PIXE.
Removal of mercury (Hg) by plants offer new options to clean up Hg-contaminated sites and at the same time harvest gold (Au). Localization of Hg and Au in the root tissues of a potential phytoremediator, cassava (Manihot esculenta), was investigated by micro-Proton Induced X-ray Emission (micro-PIXE) spectrometry to gain a better understanding of Hg and Au uptake. Plants were exposed to different Hg and Au concentrations for 6d. Qualitative elemental micro-PIXE analysis revealed that Hg and Au was found inside the root tissues for both 50 µM and 100 µM. Interestingly, plant exposure to equimolar concentrations (50 µM Hg + 50 µM Au) revealed both elements to be localised only in the epidermis, in contrast to when the plants were exposed to either Hg or Au alone. Lastly, when the Hg concentration is increased relative to the Au concentration (100 µM Hg + 50 µM Au), Au was found to be strongly localised in the epidermis while Hg was found inside the roots. These results suggest a plausible metals uptake competition. Given its ease in cultivation and harvest as well as the high Hg and Au accumulation in the roots, cassava is a suitable candidate for Hg and Au phytoremediation.
Spatial distribution of mercury and gold in roots of cassava (Manihot esculenta) by micro-PIXE.
Removal of mercury (Hg) by plants offer new options to clean up Hg-contaminated sites and at the same time harvest gold (Au). Localization of Hg and Au in the root tissues of a potential phytoremediator, cassava (Manihot esculenta), was investigated by micro-Proton Induced X-ray Emission (micro-PIXE) spectrometry to gain a better understanding of Hg and Au uptake. Plants were exposed to different Hg and Au concentrations for 6d. Qualitative elemental micro-PIXE analysis revealed that Hg and Au was found inside the root tissues for both 50 µM and 100 µM. Interestingly, plant exposure to equimolar concentrations (50 µM Hg + 50 µM Au) revealed both elements to be localised only in the epidermis, in contrast to when the plants were exposed to either Hg or Au alone. Lastly, when the Hg concentration is increased relative to the Au concentration (100 µM Hg + 50 µM Au), Au was found to be strongly localised in the epidermis while Hg was found inside the roots. These results suggest a plausible metals uptake competition. Given its ease in cultivation and harvest as well as the high Hg and Au accumulation in the roots, cassava is a suitable candidate for Hg and Au phytoremediation.