Phytoremediation of uranium-contaminated soils by wheat and sunflower plants

Nowadays, environmental pollution and its consequences have become one of the most serious human concerns, and management of pollution caused by the entry of hazardous substances such as radionuclides, pesticides, and heavy metals into the environment is of particular importance. Advances in technology and nuclear knowledge have led to increasing of release and accumulation of nuclear waste and radionuclides in the environment. Mining, production and processing of nuclear fuels and military operations are the most important causes of nuclear waste production. Because of the possibility of transferring radionuclides to the food chain, soil contamination with these pollutants creates many hazards to human health. There are various physical and chemical methods to eliminate nuclear waste, but most of them are expensive and complex. Phytoremediation is an emerging technology that uses plants and their associated microbes to clean up the polluted environment. This process is very simple, practical, economical and environmentally friendly. In this research, wheat and sunflower plants were used to remove uranium from soils of Saghand and Bandar Abbas mine's districts. Also, the effect of different concentrations of citric acid on the plants accessibility to this element was investigated.

PH meter and X-ray fluorescence spectroscopy were used to determine the pH and constituents of the soil. Also, liquid scintillation analysis was applied to determine the concentration and amount of uranium absorption.

In general, sunflower had better efficiency in absorption of uranium from soil of Saghand. In the case of uranium absorption from soil of Bandar Abbas, Wheat had better efficiency in the absence and low concentrations of citric acid, but with increasing acid concentration the accessibility of sunflower to the uranium in the soil increased.

In comparison to wheat sunflower had a better performance in uranium uptake from Saghand soil before and after acid addition. In the case of uranium uptake from Bandar Abbas soil, wheat had better performance in the absence of citric acid and in its low concentrations, while with increasing acid concentration, the uranium uptake by sunflower increased.