Kinetics of radionuclides and heavy metals behaviour in soils: Implications for plant growth
The extent of metal and radionuclide contamination in the world is immense. In soils, metals and radionuclide can be dissolved in solution, or ion exchanged in reaction, complexed with soil organics or precipitate as pure or mixed solids. Soluble contaminants are subject to migration with soil water, uptake by plants or aquatic organisms or loss due to volatilization. Lead, chromium, zinc, arsenic and cadmium are the most frequently identified inorganic contaminants in soil and ground water. Unlike degradable organic contaminants and ever short-lived radionuclides that can become less toxic over time, metals can be considered conservative. However, many metals, especially radio-sensitive elements such as arsenic and chromium can undergo transformation or sorption reaction that alter both mobility and relative toxicity. This paper therefore, makes a review of these behaviours of radionuclides and heavy metals in soils, in connection to soil contamination and their effects on plant growth.