抄録
Most metal(loid)s do not undergo degradation and persist long after their introduction into the environment. With greater public awareness of the implications of contaminated soils on human and animal health, the development of technologies for the management (remediation) of contaminated sites has attracted increasing interest amongst scientists and engineers. Remediation options for ensuring a diffuse distribution of metal(loid)s generally include amelioration of soils to minimise metal(loid) bioavailability. This can be accomplished through chemical and biological immobilisation of metal(loid)s using a range of inorganic compounds, such as lime and phosphate (P) compounds, as well as organic compounds. More localised metal(loid) contamination can be remediated by increasing bioavailability through mobilisation processes such as bioremediation (including phytoremediation) and chemical washing. A number of amendments are used either to mobilise or immobilise heavy metal(loid)s in soils. The basic principle underlying mobilisation techniques is the release of metal(loid)s into soil solution, which are subsequently removed by soil washing or uptake by higher plants. In contrast, immobilisation techniques entail the removal of metal(loid)s from soil solution either through adsorption, complexation or precipitation reactions, thereby rendering the metal(loid)s less bioavailable for plant uptake and leaching into groundwater. In this paper, the role of various inorganic and organic soil amendments in controlling the interactions of metal(loid)s and their subsequent (im)mobilisation in soils is examined with regard to the remediation of metal(loid)-contaminated soils.
