天然水体溶解性有机物(DOM)分级组分对典型城市源污染的荧光响应

运用化学(树脂)分级方法和三维荧光光谱技术,从总体溶解性有机物(DOM)到DOM各分级组分,逐步深入考察其总体分级特征及各组分三维荧光特征对典型城市生活源污染的响应特征和机理. 总体DOM分级特征对污染的产生和变化响应较弱,而DOM的分级组分对生活源污染具有较好的响应特性. DOM的总体分级特征表明,无污染的源头水DOM中以憎水酸(HoA)为主(相对含量最高),其次为亲水性物质(HiM),而受污染水体DOM中的憎水性碱和中性物质(HoBN)及弱憎水酸(WHoA)的绝对含量和相对含量均明显增高,表明用HoBN和WHoA组分相对含量的增加指示污染的增加具有一定的可行性. 研究各分级组分的三维荧光光谱结构特征表明,HoA,HoBN及HiM均对城市源污染具有良好的响应特性,受污染水体的HoA和HoBN组分荧光特征信息更为突出和丰富,且主要为具有紫外吸收的生物代谢类蛋白物质;最为特异的是WHoA组分,其在源头水中主要为含共轭结构的富里酸类物质,而在受污染水体中该类物质几乎消失且荧光响应也急剧降低. 分析式分级法获得的水体DOM主要分级组分对城市源污染具有较好的响应特性. 

Florescence Responses of Dissolved Organic Matter (DOM) Fractions to Typical Urban Source Pollution in Natural Water

The entire dissolved organic matter (DOM) and its fractions in natural water were investigated by resin fractionation and 3D fluorescence techniques to reveal their mechanisms and response characteristics to typical urban source pollution. The first stage fractionation result of DOM showed that hydrophobic base and neutral fraction (HoBN) and weakly hydrophobic acid (WHoA) had some degree of response to urban source pollution, and the amount of dissolved organic carbon (DOC) and relative proportions of both fractions increased dramatically in urban-polluted water. Further results of the 3D-fluorescence characteristics of each fraction in DOM showed that hydrophobic acid (HoA), HoBN and WHoA all had favorable responses to urban source pollution in natural water. The fluorescence response and characteristics of HoA and HoBN in polluted water were relatively prominent and abundant, and were mainly emitted by protein-like matter with UV absorbance. The WHoA varied especially strongly when it was transported from non-polluted source areas, where it was fulvic-like matter with π-structure, to urban water, where it almost disappeared and had a sharply depressed fluorescence response.