环境化学
丁爱芳,潘根兴,李恋卿.太湖地区几种水稻土团聚体颗粒组中PAHs的分布及其环境意义[J].环境科学学报,2006,26(2):293-299
太湖地区几种水稻土团聚体颗粒组中PAHs的分布及其环境意义
- Distribution characters and the environmental significance of PAHs in particle size fractions of selected paddy soils from the Tai Lake region, China
- 基金项目：国家自然科学基金重点项目(No.40231016)
- 作者
- 单位
- 丁爱芳
- 1. 南京农业大学农业资源与生态环境研究所, 南京 210095; 2. 南京晓庄学院地理系, 南京 210037
- 潘根兴
- 南京农业大学农业资源与生态环境研究所, 南京 210095
- 李恋卿
- 南京农业大学农业资源与生态环境研究所, 南京 210095
- 摘要：以太湖地区代表性的青紫泥、黄泥土、白土等3种水稻土为研究对象,采用低能量分离-分散法提取得到不同粒径的团聚体颗粒组,用HPLC测定了本土和分离得到的团聚体颗粒组中16种PAHs的含量.结果表明,供试水稻土不同粒径的团聚体颗粒组中PAHs含量分布存在差异,PAHs总含量以<2μm粒径的团聚体颗粒组最高,其次是200～2000μm粒径的团聚体颗粒组,PAHs在这2个团聚体颗粒组有明显富集现象(富集系数为1.25～3.92);而20～200μm和2～20 μm粒径的团聚体颗粒组中PAHs含量小于本土,呈现亏缺现象(富集系数为0.64～0.88).考虑到不同粒径团聚体颗粒组的相对组成,水稻土中PAHs主要分布于20～200μm和200～2000μm 2个团聚体颗粒组中,而在<2μm粒径的团聚体颗粒组中最少.PAHs在不同粒径的团聚体颗粒组中的含量分布与其总有机碳、腐殖质碳、胡敏酸碳的含量有关,并在很大程度上受芳构化疏水性有机物含量的控制.因此,水稻土不同粒径团聚体颗粒中有机碳及其组分的性质影响着这些团聚体颗粒组分对PAHs的吸持与固定.
- Abstract：Top soil of three dominant types of paddy soils were collected from the Tai Lake region, China. And soil particle size fractions were separated using low-energy dispersion procedure. Concentration of PAHs of 16 species both in bulk samples and their particle size fractions were determined by HPLC. The concentration of the total PAHs varies with the size of the particle fractions, which the order from higher level to lower is in those of <2 μm, 200～2000 μm, 20～200 μm and 2～20 μm. Compared to that of bulk samples, PAHs are enriched either in the sand-sized or in the clay-sized fractions (with an enrichment ratio of 1.25～3.92) and depleted in the silt-sized fractions (with an enrichment ratio of 0.64～0.88). Taking into consideration the composition of size fractions of the soils, large proportion of PAHs are found in the size fractions of 20～200 μm and 200～2000 μm with minor contribution by the size fraction of <2 μm. There existed a general correlation of the total PAHs content with the contents of soil organic carbon, humus carbon and humic acid carbon respectively. The contents of total PAHs in these different size fractions are mainly controlled by the organic carbon content and its structure, especially by its aromaticity. Thus, retention of PAHs in soil aggregates of the paddy soils are modulated by soil organic carbon and its property of reactive groups.
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