西南地区典型坡耕地农作物风险评价及土壤中Cd的特征研究

Risk Assessment of Crops and Study on the Characteristic of Cd in Soil of Typical Sloping Farmland in Southwest China

通过对万源市4个乡镇的耕地土壤进行重金属污染特征调查,探究研究区农作物中重金属含量与土壤污染的相关性。结果表明,引起土壤污染的重金属并不能全部迁移转化进入农作物中,且土壤污染严重地区的农作物中重金属含量处于食用安全限值以内,两者之间并没有明显的相关性。研究区4个乡镇土壤重金属污染程度从大到小依次为庙子乡>大竹镇>旧院镇>白羊乡,庙子乡玉米、马铃薯、四季豆、茶叶、花生中As、Cd、Pb等有害重金属含量均未超标,可以安全食用。但若长期大量食用庙子乡种植的农作物,谷物类作物中的Cd和叶菜类蔬菜中的Pb可能会在人体中富集,对人体健康造成危害。对影响土壤中Cd含量的因素研究结果显示,土壤Cd含量高低受到地层、成土母岩、土壤酸碱度的影响。

The correlation between heavy metal content in crops and soil pollution in the study area was explored by investigating the characteristics of heavy metal pollution in cultivated soil of four towns in Wanyuan City.The results showed that the heavy metal leads to soil pollution could not migrate and transfer into crops fully,and the contents of heavy metal in the crops was within the safe limits in the area where soil was polluted badly,there was no obvious correlation between them.The pollution degree of heavy metals in the soil of the four townships in the study area was Miaozi Township>Dazhu Town>Jiuyuan Town>Baiyang Township in descending order.The harmful heavy metal,such as As,Cd,Pb of corn,potatoes,kidney beans,tea leaf and peanuts in the Miaozi Township was not exceed standard,and were safe to eat.However if people eat the crops planted in Miaozi Township chronically and in strength,the Cd in cereal crops and the Pb in the leafy vegetables will enrich in their body,and do harm to their health.The results about the factors affect the contents of Cd in soil showed the contents of Cd in soil affected by formation,soil-forming rock and soil pH.