Analyses And Regulation Cadmium Pollution Of Soil-vegetables System In Suburb Of Guiyang

This article took the suburb allot soil planting vegetables of Guiyang as the object of study,and reseached cadmium and their correlation,then estimates the polluted cadmium in soil and vegetable by collecting 76 plough samples,base samples and meanwhile collecting 210 vegetable samples.In addition,the decoposed cadmium experiment was also made.Results were show as following:1.The cadmium in plough from different subsurb of Guiyang was great variation, and the average contents of cadmium tested followed the order of Baiyun＞Xiaohe＞Wudang＞Huaxi,and the average contents were 1.670mg/kg.The average content of cadmium in the soil of different pH was alkalinity soil＞neutral soil＞acid soil. The total cadmuin in suburb allot plough was significant correlated with the pH,of which the organic material and total N had a plus correlation,while had a minus correlation with the physical partical.2.The excess proportion and polluted degree of cadmium in suburb allot plough were Baiyun＞Wudang＞Xiaohe＞Huaxi,and the excess proportion of all suburb was 76.32%,of which 26.38%was clean degree,56.58%was less polluted degree and 18.42%was middle polluted degree,in addition,a little was seriously polluted.The accumulative proportion of average content and sample in suburb allot plough were 16.65%and 69.74%,which told that the cadmium of suburb allot mostly came from out accumulative.3.The different kinds of cadmium in vegetable was analyse by Tessier,results showed that each percentage of the water dissolved cadmium,the changed cadmium, the carbonated cadmium,the iron and manganese oxidation cadmium,the organic cadmium and the residual cadmium was 0.39%,6.38%,9.42%,8.31%,4.13%and 71.37%.The extracted capacity of different extracted matearials followed the order of NH₄OAc＞HCl＞CaCl₂＞Mg(NO₃)₂＞EDTA-NH₄OAc.The EDTA-NH₄OAc that would be avaible index to reflec the quantity and avaiblity of cadmium.4.The difference of cadmium's average content in different surburb was Xiaohe＞Baiyun＞Wudang＞Huaxi,and the average content in different vegetables was Chinese mustard＞uncooked vegtable＞lettuce＞celery＞chinese white cabbage＞purple cabbage＞scallion＞crowndaisy chrysanthemum＞gralic＞celery＞Cabbage＞gymra cusimbua＞broccoli;and the average excess proportion in different vegetables was Chinese mustard＞c＞indian rorippa heb＞coriander heb＞water spinach＞celery＞lettuce)＞purple cabbage＞chinese cabbage＞crowndaisy chrysanthemum＞gralic＞scallion＞cabbage＞gymra cus imbua＞broccoli.5.The excess proportion and average index of vegetable were Xiaohe＞Baiyun＞Wudang＞Huaxi;the excess proportion of vegetable was Chinese mustard＞uncooked vegtable＞indian rorippa heb,water spinach＞purple cabbage＞chinese cabbage,lettuce,and gralic,scallion,crowndaisy chrysanthemum,cabbage,chinese white cabbge,broccoli,gymra cusimbua and coriander heb all didn't exceed the standard;the average polluted index of vegetable was Chinese mustard＞uncooked vegtable＞indian rorippa heb＞celery＞coriander heb＞lettuce,coriander heb＞chinese cabbage＞purple cabbage,water spinach＞scallion,crowndaisy chrysanthemum＞gralic＞spring nonion,cabbage＞gymra cus imbua＞broccoli.Compared with excess proportion and average polluted index of vegetable,garlic,spring nonion,crowndaisy chrysanthemum,green vegetable,cabbage,gymra cusimbua,cauliflower were all safe vegetables.6.The changed cadmium,water dissolved and changed cadmium in soil had a plus correlation with the cadmium in vegetable,and the quantity of cadmium by 1.0 mol/LNH₄OAC extracted also had a plus correlation with the cadmium in vegetable. So taking the quantity of cadmium by 1.0 mol/LNH₄OAC extracted as the effective index by vegetable absorbed.7.Using the lime in acid soil could abase the cadmium contents in vegetable,and the average abased degree was 24.26%;using the organic fertilizer in acid soil could abase the cadmium contents in vegetable,and the average abased degree was 54.53%; using the organic fertilizer in neutral soil and lime's soil could increase the cadmium contents in vegetable,and the average degree was 27.36%;using the charcoal in soil could remarkably increase the cadmium contents in vegetable,and the average degree was 31.93%.