Migration Characteristics and Risk Assessment of Heavy Metals in Farmland Soil-Wheat System
Winter wheat is one of the main food crops in China.The enrichment characteristics and potential risks of heavy metals were discussed to provide reference for rational planting of wheat and grain safety and quality.The contents of Fe,Mn,Cu,Zn,Cr,Ni in soil and wheat grain samples collected from typical farmland in northern Henan were determined,and the pollution and ecological risk of heavy metals were evaluated.The results showed that the average contents of Fe,Mn,Cu,Zn,Cr,Ni in soil were 11397.33,287.83,23.33,7.41,31.41 and 8.56 mg/kg,respectively.Most of the elements showed a significant positive correlation;the single pollution evaluation and comprehensive pollution evaluation of Cu,Zn,Cr,Ni were clean.The average contents of Fe,Mn,Zn,Cu,Cr,Ni in wheat grains were 30.42,61.75,23.17,1.52,0.28 and 0.16 mg/kg,respectively.There was a significant positive correlation between individual elements.The contents of Fe,Zn,Cu were lower than the maximum tolerable content of wheat,and the content of Mn was higher than the maximum tolerable content of wheat.The comprehensive pollution evaluation of Cr was mild pollution,and the pollution evaluation of Ni was clean.There was a synergistic or antagonistic effect between heavy metals in the soil-wheat system.The enrichment coefficient of wheat grain to soil heavy metals was Zn>Mn>Cu>Ni>Cr>Fe.The risk of heavy metal pollution in farmland soil in northern Henan is low.