皖江经济带土壤Cd空间分布特征与生态风险评价

选取2.5 km×2.5 km网格布点法,在皖江经济带A、B、C三地分别采集土壤样品35个、34个、106个,利用ICP-AES分析测定Cd含量特征,运用单项污染指数法、地累积指数法和潜在生态风险指数法对三地土壤Cd污染状况进行生态风险评价。结果表明：（1）A、B、C三地土壤的Cd含量的算术平均值分别为0.40 mg?kg ^-1、0.66 mg?kg ^-1、0.84 mg?kg ^-1,均高于江淮流域Cd含量土壤背景值;（2）三地土壤pH在5.06~7.58之间,整体上处于酸性和弱碱性之间,pH小于7.0的样品167个,占比95.43%;（3）研究区三个地块土壤Cd污染特征存在明显的空间分异,低污染区在空间上呈带状分布,高污染区在空间上呈岛状分布,污染区分布面积C地>B地>A地。（4）三地土壤环境均受重金属Cd污染的影响,存在生态安全风险,风险大小为C地>B地>A地,风险程度均为潜在生态风险高于地累积生态风险高于单项污染生态风险。本区域土壤农业安全利用需要加以重视并进行分类管控。

Spatial distribution characteristic of Cd in soils and its ecological risk assessment in the economic belt of Yangtze River in Anhui

The numbers of 35, 34 and 106 of soil samples in the economic belt of the Yangtze River in Anhui were collected at A, B and C sampling sites by the grid points of 2.5 km× 2.5 km, respectively, the Cd content was measured by ICP-AES, and single factor pollution index, geoaccumulation index and potential ecological risk index were selected to assess the environmental risk of Cd at the three sites. The results showed that: (1) The average values of Cd content were 0.40, 0.66 and 0.84 mg?kg ^-1 in soils of A, B and C sites, respectively, which were higher than the background values of Cd content in the soils of Yangtze-Huaihe river basin of Anhui. (2) The pH values of soils at the three sites were 5.06-7.58, which was between acidic and weakly alkaline. The number of samples with pH less than 7.0 was 167, accounting for 95.43% of the total number. (3) The low pollution area is distributed as a ribbon in space, while the high pollution area is distributed as an island in space of the three sites; different soil types have different pollution characteristics of Cd. (4) The assessment results were identical and presented as follows: site C > site B > site A by the single factor pollution index, the geoaccumulation index and the potential ecological risk index. In conclusion, we should focus on the safe utilization of soils and give targeted guidance to the study regions.