洞庭湖退田还湖滩地杨树人工林土壤DDT残留特征及风险评价  

Distribution of DDT in Beach Soils of Poplar Plantation for Converting Cropland into Lake in Dongting Lake Area and Its Risk Evaluation

作　　者：李永进[1] 汤玉喜[1] 吴敏[1] 唐洁[1] 

机构地区：[1]湖南省林业科学研究院,长沙410004

出　　处：《东北林业大学学报》2010年第5期66-67,87,共3页Journal of Northeast Forestry University

基　　金：国家"十一五"科技支撑项目(2006BAD03A1503)

摘　　要：为了评估洞庭湖滩地退田还湖后杨树人工林土壤中DDT的残留特征和生态危害情况,对杨树人工林土壤中DDT的质量分数及它们的异构体组成进行了分析。结果表明:洞庭湖退田还湖滩地杨树人工林表层土壤中DDT残留很普遍,DDT质量分数平均值为3.5788μg/kg,质量分数范围为2.7450～4.9964μg/kg,DDT的质量分数均远低于国家土壤环境质量标准中的自然背景值;DDT异构体之间的质量分数也存在差异,p,p'-DDT的残留量最大,p,p'-DDD的残留量最低;DDT与土壤有机质质量分数之间几乎没有相关性;土壤中DDE/DDT的比值绝大部分大于1,DDT/(DDD+DDE)比值均大于1,表明该样地大部分地点DDT降解环境为好氧条件,并且该地区有新的DDT输入。另外,洞庭湖滩地杨树人工林土壤中DDT生态风险较低,但由于存在新的输入源,存在潜在的生态风险。Content of DDT （dichlorodiphenyhrichloroethane） in beach soil of converting cropland into lake in Dongting Lake area was determined and its isomeric composition was analysed, aimed to discuss the distribution of DDT in the beach soil of poplar plantation in Dongting Lake area after conversion and to assess its potential toxicity to the environment. Results showed that DDT was detected out in all the soll samples collected from the surface layer, with an average content of 3.578 8 txg/kg ranging from 2. 745 0 to 4.996 4. The contents of DDT in these soil samples were far less than 50 p.g/kg, an upper limit of the norm for DDT set by the state for quality of the first-class soil. The contents of p,p＇-DDT among DDT isomers were the highest, but the contents of p,p＇-DDD were the lowest. DDT was not proportional to soil organic matter. The ratios of DDE to DDT were greater than 1 in most soil samples and ratios of DDT to DDD＋DDE were higher than 1 in all the samples, indicating that the soils were mostly in an aerobic environment and there was new DDT input in beach soil of con- vetting cropland into lake in Dongting Lake area. Analysis shows that DDT residue in the soil in the study area is relatively low, but the ecological risk of DDT in the soil still exists because of the new DDT inputs.

关 键 词：洞庭湖 滩地 退田还湖 土壤 滴滴涕(DDT) 风险评价 

分 类 号：X825[环境科学与工程—环境工程] S156.91[农业科学—土壤学]