长江三角洲地区土壤和水稻重金属污染特征研究

Characteristics of Heavy Metal Pollution in Soil and Rice of Yangtze River Delta Region

[目的]研究长江三角洲地区土壤和水稻重金属污染特征。[方法]测定长江三角洲地区150多个采样点的重金属含量,进行土壤环境质量评价,并研究重金属元素在不同区域和植物不同部位的含量分布以及转换和分配特征。[结果]长江三角洲地区受Cd、Pb、Cr、Cu、Zn的污染,其中Cd污染最严重,Pb、Cu和Zn次之,Cr最轻,几乎不受Hg和As的污染,内梅罗污染指数为0.880,属于警戒级;水稻果实中Cd、Cr、Cu、Hg和Zn超过其背景值。按区域划分,土壤污染程度依次为:环太湖地区>浙江南部地区>沿江地区,城市直辖区>县级城镇及农村;按迁移转化规律划分,根际土壤>水稻根茎>水稻果实;转换系数Cd>Cu>Zn>As>Hg>Pb>Cr,分配系数Zn>Cr>Cd>Cu>Hg>Pb>As。[结论]长江三角洲地区污染元素的数值范围较大,个别样本污染严重,应加大重金属污染防治与预防。

[Objective] Characteristics of heavy metal pollution in soil and rice of Yangtze River Delta region were studied.[Method] Heavy metal contents of more than 150 sample spots in Yangtze River Delta region were determined so as to make a soil environmental quality assessment and study the content distribution,transformation and distribution characteristics of heavy metals in different regions and different plant parts.[Result] The Yangtze River Delta region was polluted by Cd,Pb,Cr,Cu and Zn,among them Cd pollution was the most serious;Pb,Cu and Zn took second place;Cr pollution came the lightest;And there was almost no Hg and As pollution.The Nemero pollution index of soil was 0.880 which was at the alert level.Cd,Cr,Cu,Hg and Zn in rice grains exceeded the background values.Heavy metal pollutions in soil divided by regions were in order of Taihu Lake region southern region of Zhejiang Province regions along the Yangtze River and municipalities towns and rural areas.Heavy metal pollutions in soil divided by moving-transiting rule were in order of rhizosphere soil rice straw rice grains.Conversion coefficients were in order of Cd Cu Zn As Hg Pb Cr.Distribution coefficients were in order of Zn Cr Cd Cu Hg Pb As.[Conclusion] There was a larger value range of pollution element in the Yangtze River Delta region,moreover individual samples had serious pollution,so the prevention and control of heavy metal pollution should be strengthened.