三峡库区农业土壤重金属含量特征及污染评价--以Cu Pb和Zn为例

Heavy Metal Concentrations in Agriculture Soils of the Three-Gorge Reservoir Area and Their Pollution Evaluation——Taking Cu,Pb,and Zn as Examples

通过田间采样和室内分析,对重庆市三峡库区6个区(县)(丰都、奉节、江津、万州、武隆和忠县)农业土壤中Cu、Pb和Zn的含量特征进行了调查研究,并同时对其污染状况进行了评价。结果表明,重庆市三峡库区农业土壤Cu、Pb和Zn全量的平均值分别为(29.96±12.80)mg·kg-1、(25.45±8.80)mg·kg-1和(64.79±18.79)mg·kg-1;其有效态含量的平均值分别为(1.66±1.36)mg·kg-1、(1.67±1.24)mg·kg-1和(2.95±3.02)mg·kg-1;3种重金属有效态含量变异均明显大于全量的变异;Cu、Pb和Zn有效性系数分别为(5.53±3.77)%、(7.52±7.18)%和(4.36±4.14)%。各区(县)农业土壤Cu、Pb和Zn的有效态与其全量间均呈显著或极显著正相关;Cu、Pb和Zn全量两两间也呈现显著或极显著正相关。各区(县)农业土壤重金属单因子污染状况均表现为Cu>Zn>Pb;各区(县)农业土壤重金属综合污染指数平均值为0.38±0.20,属安全等级,表明调查区域土壤清洁。

The heavy metal concentrations in agricultural soils are directly associated with food safety and human health. In this study,the concentrations of Cu,Pb and Zn in agrieuhural soils in Fengdu, Fengjie, Jiangjin,Wanzhou,Wulong and Zhongxian counties of Chongqing in the Three Gorges Reservoir （TGR） area were determined,and their polluted status were evaluated. The results showed that the total concentrations of Cu,Pb and Zn in the agricultural soil of Chongqing in the TGR area were （29.96 ±12.80）mg ·kg^-1, （25.45 ±8.80）mg·kg^-1 and （ 64.79± 18.79 ）mg·kg^-1; respectively,and the average available concentrations of Cu,Pb and Zn were （ 1.66± 1.36 ）mg·kg^-1, （ 1.67± 1.24 ）mg·kg^-1 and （2.95±3.02）mg·kg^-1, respectively. The available coefficients of Cu,Pb and Zn were （5.53±3.77）%, （7.52±7.18）% and （4.36±4.14）%, respectively. The variability of three heavy metal elements in the soils was much more than their total concentrations. The available concentrations of Cu, Pb and Zn in the softs were highly associated with their total concentrations. There were significantly positive or positive relations between total Cu and total Pb, total Pb and total Zn, and total Cu and total Zn. The polluted status sequence of heavy metals in agricultural soils of Chongqing in the TGR area was followed by Cu〉Zn〉Pb according to the monomial pollution index. The soil＇s comprehensive pollution index of Cu, Pb and Zn was 0.38±0.20, suggesting that the soils investigated in TGR area were clean and safety according to the standard of the second grade of GB 15618--1995.