[In situ immobilization remediation of heavy metals-contaminated soils: a review].
In situ immobilization of heavy metals in contaminated soils by adding extraneous active amendments has been considered as a cost-effective measure for contaminated soil remediation. Application of immobilization amendments can decrease the available fractions of heavy metals or change their redox states, and thus, effectively decrease the mobility, bioavailability, and toxicity of the heavy metals in soils. This paper summarized the present researches about the in situ immobilization of heavy metals in soils, including kinds of immobilization amendments, research methods, immobilization indexes, immobilization mechanisms, and relevant environmental risk assessment. The mostly applied amendments include clay minerals, phosphates, organic composts, and microbes. Due to the complexity of soil matrix and the limitations of current analytical techniques, the exact immobilization mechanisms have not been clarified, which could include precipitation, chemical adsorption and ion exchange, surface precipitation, formation of stable complexes with organic ligands, and redox reaction. The prospects and limitations of in situ immobilization of heavy metals in soils were discussed. Future work should focus on the elucidation of immobilization mechanisms at molecular scale, with specific attention be paid to the potential risks of applying immobilization amendments and its long-term effects on field soils.
Wang
Li-Qun
LQ
Capital Normal University, Beijing 100037, China. liqun2080@yahoo.com.cn
Luo
Lei
L
Ma
Yi-Bing
YB
Wei
Dong-Pu
DP
Hua
Luo
L
D000538:Aluminum Silicates / Q000737:chemistry; D001419:Bacteria / Q000378:metabolism; D001673:Biodegradation, Environmental; D002681:China; D000077215:Clay; D004787:Environmental Pollution / Q000517:prevention & control*; D019216:Metals, Heavy / Q000032:analysis / Q000378:metabolism*; D010710:Phosphates / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism*
D000538:Aluminum Silicates; D019216:Metals, Heavy; D010710:Phosphates; D012989:Soil Pollutants; D000077215:Clay