| 有机氯农药污染场地表层土壤有机-矿质复合体中污染物的分布 |
| 摘要点击 2658 全文点击 2376 投稿时间：2008-02-05 修订日期：2008-04-08 |
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| 中文关键词 有机氯农药 污染场地 表层土壤 有机-矿质复合体 |
| 英文关键词 organochlorine pesticides(OCP) contaminated site topsoil organo-mineral aggregates |
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| 中文摘要 |
| 采用湿法物理分级方法将北京市某农药厂遗留场地表层土壤分成4种粒径的有机-矿质复合体组分:粘粒、粉粒、细砂和粗砂（<2 μm、 2～20 μm、20～200 μm、>200 μm），研究有机氯农药在其中的分布特征及土壤不同有机-矿质复合体组分中有机质和矿物质组成的差异对污染物赋存分布的影响.结果表明，污染物质六六六（HCHs）和滴滴涕（DDTs）在粉粒中分布较多，含量分别为463.1 mg·kg-1和1 225.6 mg·kg-1，粗砂中分布最少, 含量仅为157.8 mg·kg-1和384.5 mg·kg-1.lgKoc与污染物质在粘粒上的分布量存在显著的相关关系.通过对有机-矿质复合体进行X射线衍射分析发现，场地土壤粘粒和粉粒中粘土矿物含量较高.由于有机-矿质复合体中粘土矿物组成和含量存在差别，这在一定程度上影响了污染物质在其中的分布.同时，所研究的场地土壤中污染物易于富集的粒径范围与报道的北京大气颗粒物上HCHs和DDTs有较多吸附的粒径相近.因此，应当重视污染场地表层土壤对大气污染的可能贡献及其环境风险. |
| 英文摘要 |
| Four different soil particle-size fractions that is clay, silt, fine sand and coarse sand (<2 μm,2-20μm, 20-200μm, >200μm) from the topsoils in an organochlorine pesticide (OCP) field were separated by physical method to characterize the OCPs distribution in soils and to study the effect of organic matter and mineral composition in different separates on pollutants distribution. The results show that the concentrations of HCHs and DDTs in silt with 463.1 mg·kg-1and 1 225.6 mg·kg-1 are higher than those in coarse sand, 157.8 mg·kg-1 and 384.5 mg·kg-1, respectively. There is a significant correlationship between lgKoc and the contents of HCHs and DDTs in clay. The analysis on X-ray diffraction of organo-mineral aggregates demonstrates that clay and silt have a much higher content of the clay minerals than those in coarse sand within the contaminated soils. There are some differences with different particle-size fractions in the content and composition of the clay minerals in organo-mineral aggregates, which affect the OCP distribution in soils to some extents. The results also suggest that the distribution of HCHs and DDTs in the particle with more pollutants in the site is similar to that in airborne particles. So the environmental behavior of OCPs in topsoils from the contaminated site should be paid more attention especially in ambient air-soil interaction. |
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