Screening Of Sensitive Vegetables Of Mercury And Study On The Main Controlling Factors Of Soils

Due to the high economic value,the large multi-population index and the increasing market demand for vegetables,the problem of heavy metal pollution in the soil is becoming more and more prominent.How to ensure that vegetables can be safely produced in large areas contaminated by heavy metals is a major problem that we need to solve urgently.Screening low-accumulation vegetable varieties is an effective method to solve the safe production of vegetables on heavy metal-contaminated land Because there are interspecific differences in the ability of different vegetables to absorb and enrich heavy metals.In this paper,two kinds of typical vegetables（leaf and root vegetables）widely planted were collected,and 20 representative soils were collected in the country.Hg salt solution was added exogenously according to the current national soil environmental quality secondary standard（medium is Hg（NO₃）₂·?H₂O）,the experiment has 3 treatments,the control treatment（CK）does not add exogenous Hg to the soil;the low Hg treatment（A）,0.3 mg·kg^-1,0.5 mg·kg^-1,1 mg·kg^-11 Hg was added to the soil with pH<6.5,6.5<pH<7.5 and pH>7.5 respectively;high Hg treatment（B）was added to the acidic,neutral and alkaline soils,0.6 mg·kg^-1,1 mg·Kg^-1,2 mg·kg^-1.Pot experiments were conducted to study the sensitivity difference of different leafy and root vegetables to Hg enrichment.According to the SSD method,and the sensitive and low-accumulation vegetable varieties were screened to explore the effects of different soil physical and chemical properties on the absorption of Hg in leafy vegetables and root vegetables,and the establishment of Hg in soil-vegetable system.The main controlling factors and prediction models of absorption and enrichment.The main results are as follows:1.Eleven kinds of leafy vegetables（water spinach,chicory,fennel,coriander,Chinese cabbage,sage,black stalk,oil wheat,Chinese cabbage,spinach and lettuce）were selected and planted in two kinds of typical acid and alkali soils（Jiangxi red soil,Shandong fluvo-aquic soil）On the basis of the sensitivity-enrichment difference of Hg,the Hg-sensitive leafy cultivars,pakchoi,and the low-accumulation Hg leafy variety,Chinese cabbage and fennel,were screened in both soils.2.Nine kinds of root vegetables（three kinds of radish,carrot and potato）were selected and planted in two typical acid-base soils（Jiangxi red soil,Shandong fluvo-aquic soil）for the sensitivity enrichment difference of Hg,and screen out the two soils.Both are Hg-sensitive root vegetables-Xiayou five-inch carrots,and low-accumulation Hg root vegetables-Dalian 501 radish and Jinghong five-inch carrots.3.The selected leafy cabbage varieties and sensitive root vegetable varieties Xiayou five-inch carrots were screened in 18 kinds of national soils.Stepwise multiple regression analysis was used and a prediction model was established to determine the edible of Chinese cabbage.Part of Hg bioconcentration factor（BCF）,Hg bioaccumulation factor（BCF）and soil properties such as pH,organic matter（OM）,cation exchange capacity（CEC）,total nitrogen（TN）,total Correlation between potassium（TK）and iron-aluminum oxides.The prediction model shows that pH and OM are the two most important factors affecting the transfer of Hg from soil to pakchoi;pH is the most important factor affecting the transfer of Hg from soil to carrot.