Decontamination of Radioactive-Contaminated Soils: Current Perspective

Abstract

Radionuclides exist in the environment naturally and, in more recent times, have been added by nuclear power and weapons. The carcinogenic nature and long half-lives of many radionuclides make them a potential threat to human health. Moreover, there is an increasing trend of uranium accumulating in soils due to a number of deliberate or wrong practices. Also, the contamination of land by natu-rally occurring radionuclides from " non-nuclear " industries include uranium min-ing and milling, metal or coal mining, radium and thorium factories, and the processing of materials containing technologically enhanced levels of natural radio-activity. As a consequence, there would be a risk for ecosystems, agro-systems, and health. It is suggested that knowledge of the mechanisms that control the behavior of such heavy metals must be improved and be used for risk assessment and propo-sition of remediation treatments. Phytoremediation has been used to extract radio-nuclides and other pollutants from contaminated sites. The accuracy and success of these applications depend on an understanding of the processes involved in plant uptake of radionuclides. The recent advances in uranium removal from contami-nated soils, using either chemical and/or biological techniques (such as hyperaccu-mulator plants, or high biomass crop species after soil treatment with chelating compounds) are reviewed and discussed.