北京市部分地区土壤中二英类物质污染水平初探

采集北京市部分非污染区土壤样品16个,对样品中二(口恶)英类物质分布形态和浓度水平进行初步探讨.结果表明:空地土壤中的二(口恶)英类物质质量分数为0.229 1～3.332 pg/g(全文均指pg(I-TEQ)/g),平均值为1.478 pg/g,与美国农村背景值相当;林地质量分数为0.769 1～2.760 pg/g,平均值为1.329 pg/g;耕地质量分数为2.278～7.307 pg/g,平均值为4.462 pg/g.与国外数据对比可以看出:空地和林地土壤样品与欧洲国家的浓度水平相当,耕地土壤则高于欧洲国家,但比日本低很多.总之,耕地土壤样品中二(口恶)英类物质的质量分数较高,空地次之,林地土壤质量分数最小.对于形态分布而言,受某种主要因素影响的土壤中二(口恶)英类物质形态分布相似,受综合因素影响的土壤与大气中的二(口恶)英类物质形态分布类似.另外讨论了浓度异常采样点可能的污染来源. 

Preliminary Study on Level and Pattern of PCDD/PCDFs in Soil in Part of Beijing City

The distribution patterns and concentration levels of PCDD/PCDFs in different soil samples from part of Beijing City were preliminarily discussed and sixteen soil samples were taken and analyzed from less-polluted area in Beijing City.Results indicate that the concentrations of PCDD/PCDFs in soil from unused land ranged from(0.229 1) to 3.332(pg/g)(avg.1.478(pg/g)),those from forest soil ranged from(0.769 1) to 2.760(pg/g)(avg.1.329(pg/g)) and those from agricultural land ranged from 2.278 to 7.307(pg/g)(avg.4.462(pg/g)).Contrast with foreign data,concentration from forest and unused samples corresponds with European countries,but much lower than Japan in Asia.In conclusion,the concentration of dioxins in agricultural land is highest,the secondary is unused land,the thirdly is forest soil.Considering pattern distribution,similar pattern of dioxin congeners is found in some soil samples affected by one dominated pollution source,and the pattern of dioxin congeners of the soil affected by integrated pollution sources is similar to that in the air.Potential pollution sources are discussed in some special sites.