北京市道路雨水径流溶解性有机物化学组分特性

Characteristics of Chemical Fractions of Dissolved Organic Matter in Road Runoff in Beijing

为探究北京市道路雨水径流溶解性有机物(DOM)的化学特性,采用三维荧光光谱、紫外-可见吸收光谱及红外光谱技术,对北京市不同交通密度道路雨水径流溶解性有机物的化学组分进行分析.结果表明,北京市道路雨水径流DOM以疏水性组分为主,且主要为疏水中性组分.道路雨水径流DOM亲水性组分主要由类芳香蛋白物质组成,疏水性组分除含大量类芳香蛋白物质外,还含有大量类富里酸物质.道路雨水径流DOM疏水性组分的芳香化程度较高、腐殖化程度较低,亲水性组分与之相反.道路雨水径流DOM酸性组分中含异构化的羧基和苯环等官能团,碱性组分和中性组分中多含醚键、酯基、酚类和醇类等官能团.交通密度对道路雨水径流DOM化学组分的物质组成、特性等无明显影响,仅影响各化学组分中的物质含量;交通密度越大,各化学组分中物质的含量越多和芳香化程度越高,腐殖化程度越低.

The characteristics of DOM chemical fractions in road runoff with different traffic density were analyzed using excitation emission matrix spectroscopy(EEMs)technology,UV-vis spectra,and FTIR spectroscopy.The results showed that hydrophobic organics were the dominant components in DOM of road runoff,and hydrophobic neutral organics was the most abundant fraction.The hydrophilic organics in DOM of road runoff were mainly composed of protein-like substances.Both protein-like substances and fulvic-like acid substances were found in the hydrophobic organic matters.A high degree of aromatization and a low degree of humification were detected in hydrophobic organics,whereas the characteristics of hydrophilic organics were opposite.Some functional groups such as isomerized carboxyl and unsaturated C=C bonds were featured in acidic organics,and ether and ester groups,phenol,and alcohol were detected in alkaline and neutral organics.The substance composition and characteristics of DOM chemical fractions in road runoff were not affected by the traffic density.Traffic density influenced the quantity of substances in each chemical fraction only.With traffic density increasing,the matter content and the aromatization degree of DOM chemical fractions in road runoff increased,whereas the degree of humification decreased.