摘要
采集长沙城郊18个乡镇513个农田土壤样点,运用模糊综合评价法和层次分析法从农田土壤重金属Pb、Cd的含量、土壤理化特性(pH值、有机质、碱解氮、有效磷)、土壤区位特征(土壤采样点离城镇的距离、离建设用地的距离、离河流的距离、离农村居民点的距离)3个方面选取评价指标,建立农田土壤重金属Pb、Cd的生态风险评价模型,并根据生态风险指数值(ERI)将生态风险等级划分为四级(Ⅰ级ERI>0.70、Ⅱ级0.6<ERI≤0.70、Ⅲ级0.4<ERI≤0.60、Ⅳ级ERI≤0.40)。结果表明,22.9%的土壤样点生态风险指数为Ⅲ级和Ⅳ级水平,具有较高的生态风险,主要分布在河流、城镇、建设用地和农村居民点的聚集区。根据各乡镇生态风险等级的差异,划分农田土壤重金属Pb、Cd的高、中、低生态风险区。农田土壤重金属的生态风险评价与分级、分区是建立农田土壤重金属生态风险防控体系的必要手段,可为农田土壤的科学合理利用提供参考。
The purpose of this study was to assess the ecological risk of heavy metals Pb and Cd in suburban agricultural soils in Changsha, the capital city of Hunan Province. A total of 513 surface soil samples（0～20 cm）were collected from paddy fields and upland covering whole city region, and the concentrations of Pb and Cd were analyzed. Fuzzy comprehensive evaluation and analytic hierarchy process were applied to establish ecological risk assessment models of Pb and Cd contamination, and evaluation indics（ERI）were set up based on Pb and Cd concentrations, soil physicochemical properties and soil location characteristics. The indics of soil physicochemical properties were soil pH, organic matter, alkali-hydro nitrogen and available phosphorus, while the indics of soil location characteristics were the distance from cropland to town, industrial construction land, river, and settlement. The ecological risk grade was divided to four ranks according to the values of ecological risk index, ERI0.70, 0.6ERI≤0.70, 0.4ERI≤0.60, and ERI≤0.40 were defined as class I, II, III and IV respectively. About 22.9% sampling points were distributed in class III and IV, most of high ecological risk soil samples were located at the surrounding area of riverside, town, industrial construction land and settlement. The ecological risk regions of farmland soil Pb and Cd were divided into high, middle, and low ranks. Therefore, the ecological risk assessment of heavy metals in agricultural soil could be important in controlling and preventing soil heavy metal contamination.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2013年第8期1564-1570,共7页
Journal of Agro-Environment Science
基金
国家"十二五"科技支撑计划项目(2012BAD14B17)
关键词
农田土壤
重金属
PB
CD
生态风险评价
agricultural soil
heavy metal
Pb
Cd
ecological risk assessment
