融雪期城市河流中溶解性有机物的时空分布特征

以沈阳市新开河为研究对象,考察了河水中溶解性有机物(DOM)含量的月份变化,以及融雪期河水中DOM含量和特性的时空变化规律.利用XAD树脂将DOM分为5个部分:疏水性有机酸(HPO-A),疏水性中性有机物(HPO-N),过渡亲水性有机酸(TPI-A),过渡亲水性中性有机物(TPI-N)和亲水性有机物(UPI).结果表明,融雪期河水中的溶解性有机碳(DOC)浓度较高,HPO-N和TPI-N是融雪期河水中的主要DOM组分,并且DOM中的荧光物质主要为类芳香族蛋白质荧光物质和类腐植酸荧光物质融雪期水体中的DOC,波长254nm处的紫外吸光度(UV-254)和三卤甲烷生成势(THMFP)呈先降低然后波动最后升高的变化趋势.特征紫外吸光度(SUVA)和三卤甲烷生成活性(STHMFP)与以上三者的变化规律相反融雪期河水中的DOC受污水排放影响大,有排污口处的DOC含量明显大于其他区域污水排放也使受纳水体中UV-254对THMFP的指示作用减弱.

Temporal and spatial variations of dissolved organic matter in urban river during snowmelt period

The monthly changes of contents of dissolved organic matter (DOM), as well as the spatial and temporal variations in contents and characteristics of DOM during snowmelt period, in the Xinkaihe River in Shenyang were investigated. DOM was fractionated using XAD resins into five fractions: hydrophobic acid (HPO-A), hydrophobic neutral (HPO-N), transphilic acid (TPI-A), transphilic neutral (TPI-N) and hydrophilic fraction (HPI). The results showed that dissolved organic carbon (DOC) concentrations in river water during snowmelt period were high. HPO-N and TPI-N were the major DOM fractions, and aromatic protein- and humic acid-like fluorescent materials were the major fluorophores in DOM, during the snowmelt period. DOC, absorbance of ultraviolet light at 254nm (UV-254) and trihalomethane formation potential (THMFP) initially increased, then fluctuated, and finally decreased during snowmelt period. The changing trend of specific ultraviolet light absorbance (SUVA) and specific THMFP (STHMFP) were opposite to the above three. DOC in river water was significantly affected by the sewage discharge during snowmelt period, and DOC near the sewage outfall was higher than other areas. The indicating function of UV-254 on THMFP in receiving waters weakened as a result of the sewage discharge.