Cadmium Accumulation In Vegetables And Its Relationship With Soil Cadmium

In recent years,the frequent emergence of cadmium rice attracted more and more attention,and people are more careful about the hazards of cadmium pollution in our country.With the development of industry,more and more soil,air and water are facing the threat of cadmium pollution.When the environment is polluted by cadmium,cadmium can accumulate in living organisms,enrich in high-level trophic organisms through the food chain,and finally enter the body through the food,water,smoking or other means.When the concentration of cadmium reaches a certain level,the human will be cadmium poisoning.Therefore,the investigation of cadmium pollution in vegetables in Cd polluted area is conducive to the understanding of the current situation of vegetable cadmium pollution in China and the further development of soil cadmium pollution prevention and control has a very important significance.This study was divided into two parts:investigation on Cd content in vegetables in Cd polluted area and the correlation between Cd and soil Cd in vegetables.The first part is the investigation of Cd content in Cd polluted area,collecting vegetables from nine provinces of Hubei,Hunan,Guangdong,Fujian and so on,which are polluted by Cd.Soil samples were collected from different levels of Cd contaminated soil according to the known soil survey data.The Cd concentration was analyzed,with the results being as following:(l)The Cd pollution situation in vegetables from various regions is different.According to the sampling and analysis,it was found that Cd contamination form Hunan area is the most serious,with 46%of vegetable samples exceeding National Food standard(0.2 mg/kg);(2)Among various kinds of vegetables,Cd concentrations in leafy vegetables were higher than other kinds of vegetables,which is in line with the factor that leafy vegetables have a higher accumulation ability;(3)Unwashed vegetables contained more Cd than unwashed,indicating parts of Cd and other elements may be derived from atmospheric deposition.The second part is pot experiments.Selected from the soil of the eight regions of Yingtan,Jiangxi,Hunan Changsha,Zhaoqing,Guangdong,Dujiangyan,Sichuan,Shandong Weifang,Chongzuo,Guangxi,Guizhou Guiyang,Baoding and Hebei,their Cd background value:0.41,0.48,0.34,0.42,0.26,0.97,1.14 and 0.27mg/kg.The soils used were spiked with one of 6 concentrations:0,0.25,0.5,1,2,4 mg/kg,with a total of 6 treatments,each with 3 replicates.Four main results were obtained as following:(l)Based on the growth condition of the vegetables,no effect on the growth was observed in all treatments.(2)As soil Cd increased,the Cd in vegetables increased correspondingly with a significant correlation of soil Cd.(3)Based on these dose-response relationship,a linear model were proposed and the total threshold limit value were calculated for each soil being:0.12mg/kg,0.37mg/kg,0.27mg/kg,0.46mg/kg,0.46mg/kg,0.96mg/kg,1.7mg/kg,0.46mg/kg.The Cd threshold follows the order:Guiyang>Chongzuo>Weifang>Dujiangyan>Baoding>Changsha>Zhaoqing>Yingtan.(4)Though the above experiments,it was also found that the correlation between Cd and Mn,Fe,Cu,Zn is low,and the values of R~2 is very low.