Study On The Migration And Influencing Factors Of Cadmium In Soil Matrix-bolet Boletus

In this paper,the B.griseus of Yunnan were used as the research object.Twenty-two growing point B.griseus samples and growing soil were collected.The content and the speciation of Cd in B.griseus were measured and explored the potential food safety risks of Cd in mushroon.The 0～5 cm soil substrates were collected from 22 growth points.The physical and chemical characteristics,mineral elements of soil substrate were measured.Multi-models were used to explored the Cd from soil to B.griseus system.The main conclusions were as fellow:1.The Cd content of the B.griseus(Cd_mushroom)collected from 22 growth points were 8.69～24.19 mg/kg DW,among which the water-soluble state were44.77～73.5%,the ion-exchange state were 8.88～46.52%,the carbonate bound state2.74～15.99%,Fe-Mn oxide bound state 1.35～6.99%,organic matter bound state0.11～2.65%and residual state 0.02～0.46%;the results showed that the Cd content of22 B.griseus were higher than the limit of Cd in edible mushroom at GB2762-2017‘National Food Safety Standards for Contaminants in Foods’（0.5 mg/kg）.The highest water-soluble state in total Cd was had potential food safety risks.2.The soil matrix corresponding to the growth of B.griseus,the soil detected were p H,the conductivity（EC）,the total soluble solids（TDS）,total dissolved organic carbon（TOC）,total carbon content（TC）,total nitrogen content（TN）,total hydrogen content（TH）,total sulfur content（TS）,Clay,Silt,Sand,lead（Pb）,chromium（Cr）,zinc（Zn）,manganese（Mn）,iron（Fe）,copper（Cu）,potassium（K）,sodium（Na）,calcium（Ca）,phosphorus（P）and others indexs,to explored different indexs affected Cd_mushroomand Cd content in soil matrix(Cd_soil).The Cd content in the soil matrix were 0.03～0.57 mg/kg DW,indicated that the water-soluble Cd was low proportion in the soil matrix,ion exchange state and carbonate binding state were accounted for a high proportion.3.The bioconcentration coefficient（BCF）of B.griseus in the soil matrix from 22growth points showed a strong bioconcentration effect.The analysis of Bouble plots showed that the Cd content of the B.griseus was positive correlation to the soil EC,TDS,TN,TC and Clay in the matrix and had a negative correlation with p H and TOC;The cluster analysis showed that Cd content of B.griseus and soil matrix were significantly related,followed by TN,TC,EC,TDS and TH.They were affected Cd migration from soil to B.griseus.In the regression analysis,drawed a conclusion Cd_mushroom=42.196+3.945 Cd_soil+0.214 EC+1.658 TC-5.432 p H-0.526 Clay+0.326 TN-0.364 TDS（r=0.793,P=0.025）,calculated quantitatively the infection of the factors.