Experiment Study On Interaction Of Heavy Metals(Cd,Pb And Zn)in Arid Oasis Soil

The interaction of heavy metals in soil-vegetable systems in oasis soils is less.Rape(Brassica campestris L.)and celery(Apium graveolens)were chosen as test crops in this study,the absorbtion and accumution characterizes of heavy metals under Cd/Zn,Cd/Pb,Pb/Zn single and combined pollution through pot experiments;the interaction of Cd,Cd was analyzed between them,and the uptake and translocation models of Cd,Pb and Zn were established.The results showed as followed.(1)The concentrations of Cd,Pb and Zn in different parts of rape and celery were all increasing as the amendment increase,when concentration of Cd in soils was less than 7.5 mg·kg-1,Pb was less than 1500 mg·kg-1 and Zn was less than 1000 mg·kg-1 under Cd/Zn,Cd/Pb and Pb/Zn single or combined contamination.(2)There was an antagonism stess between Cd and Zn under Cd-Zn combined to rape;Zn first inhibited and then promoted Cd absorbed by celery,while Cd first promoted and then inhibited Zn absorbed by celery.The enrichment ability of Cd and Zn of rape was inhibited under Cd-Zn combined stress,but the migrated ability was promoted;the enrichment ability of Cd in celery was promoted under Cd-Zn combined stress,the enrichment ability of Zn in celery was first promoted and then inhibited.The migrated ability of Cd of celery was promoted when the addition of Zn between 0.7 and 2.1 mg·kg-1,while the migrated ability of Zn in celery was inhibited when Cd was added.(3)There was an antagonism between Cd and Pb under Cd-Pb combined stress to rape;Pb first promoted and then inhibited Cd absorbed by celery,but Cd inhibited Pb absorbed by celery obviously.The enrichment ability of Cd,Pb and the migrated ability of Pb of rape were inhibited under Cd-Pb combined stress,but the migrated ability of Cd of rape was promoted;the enrichment ability of Cd was first promoted and then inhibited under Cd-Pb combined stress,while the enrichment ability of Pb in roots of celery was inhibited.(4)There was an antagonism between Pb and Zn to rape and celery.The enrichment ability of Pb in roots of rape was promoted under Pb-Zn combined stress,and the migrated ability of Pb in rape was inhibited;the migrated ability of Pb and Zn in celery was promoted under Pb-Zn combined stress.(5)The uptake and migrate models of Cd,Pb and Zn in rape and celery under Cd/Zn,Cd/Pb,Pb/Zn singly or combined contamination in arid oasis soil were all fitted quadratic equations.