The Immobilization of Cd and As in Paddy Soil-Rice by Water Managements Combined with Amendments
Soil Cd and As have become the key and challenging focus of heavy metal pollution control in agricultural fields in our country due to their opposite chemical behaviors.In order to reveal the immobilization effects and mechanisms of different water management practices using amendments on the Cd and As in polluted soil-rice systems,Conducted pot experiments with wollastonite(Wo),zero-valent iron(Fe),and Fe-modified wollastonite(Fe@Wo)as amendments,using dry-wet alternation(DF)and flooding(F)treatments.The results indicate that under dry-wet alternation(DF)and flooding(F)conditions,soil As is primarily fixed in the soil as crystalline iron oxide-bound and amorphous iron oxide-bound forms,respectively;while soil Cd predominantly exists in the form of amorphous iron oxide-bound.Water management combined with amendments can effectively reduce Cd and As concentration in soil and rice,with Fe@Wo treatment showing the best results.Under DF and F conditions,Cd concentration in rice grains was reduced by 64.40％and 73.50％,respectively,and As content was reduced by 47.43％and 53.68％,respectively.Cd concentration in the root surface iron plaque decreased to 0.63 mg·kg-1 and 89.40 mg·kg-1,and As content decreased to 0.61 mg·kg-1 and 126.24 mg·kg-1,respectively.
dry and wet alternatefloodingcadmiumarsenicrepairmechanismiron-modified wollastonite
万方数据
维普
