德阳市农用地土壤中镉的分布特征及异常来源分析

通过龙门山区域的德阳市6个县市农用地土壤中镉的采样监测,分析了该区域镉的分布特征及区域分异原因,并对其环境生态风险进行了评价。结果表明,德阳市农用地土壤中镉含量总体水平为0.11~4.68 mg/kg,呈现西北到东南逐渐降低的分布特征;西北部绵竹和什邡市农用地土壤中镉出现超标的范围较广,2个城市约62.5%的监测点土壤中镉出现超标,且绵竹市农用地土壤中镉超标程度和生态风险程度最重,绵竹地区约25%的监测点土壤中镉出现了轻中度超标;监测区域土壤中镉出现较重生态风险点共有4个,均出现在绵竹;但较高含量的镉在该区域并非大范围连片存在;区域农用地土壤中镉异常的来源主要为龙门山中段的地质背景和部分以矿石为原料企业的综合影响。

The Distribution Character and Analysis of Anomaly Sources of Cd in the Agricultural Soil in Deyang City

Through the systematically sampling and monitoring in the farmland in the six counties of Longmen mountain area of Deyang City, this article analyses the distribution character of Cd and the reasons of the anomaly sources of Cd in the area, and evaluates the environmental risk of Cd. The outcome indicates that the general concentration of Cd in the farmland of Deyang City is between 0.11-4.68 mg/kg, and the distribution pattern of the concentration of Cd is high in the northwest and low in the southeast; the area where the level of Cd exceeds the standard in the farmland of the counties of Mianzhu and Shifang in the northwest of Deyang is large, and the ratio of the soil monitoring points where the level of Cd exceeds the standard in the farmland is 62.5% respectively. The degree of the concentration of Cd exceeds the standard in the farmland is relatively serious in the Mianzhu County, and the same as the degree of the environmental risk of Cd; there are four soil points where the degree of the environmental risk of Cd is severe in Deyang City and they are all located in Mianzhu County. But the area of high concentration of Cd in the farmland is not large and continuous, and the anomaly sources of Cd in the northwest in the agricultural soil in Longmen mountain area of Deyang City mainly is the comprehensive effect from the geological background of the Longmen mountain and some ventures whose raw material is ore.