三维荧光光谱区域积分法解析辽河七星湿地水体DOM组成及来源

Characterization of DOM Composition and Origin Using Three-dimensional Fluorescence Spectroscopy Coupled with Region Integration Method in Qixing Wetland

  • 摘要: 监测了七星湿地水体水质,并采用三维荧光光谱技术结合荧光区域积分(FRI)分析法研究七星湿地水体中溶解性有机物(DOM)荧光特性,分析DOM组成、腐殖化程度、污染来源与其他水质指标之间的相关性。结果表明,七星湿地对于支流水体有一定的净化作用,出水CODCr满足GB 3838—2002的Ⅴ类水质标准,氨氮及总磷仍然是水体中的主要污染物;荧光指数(f450/500)平均值为1.82,表明七星湿地DOM主要是生物来源;腐殖化指数(rB,D)整体较低,表明湿地水体腐殖化程度较高,有机物污染较为严重。通过荧光区域积分法将荧光光谱图划分为五大类,其中芳香性蛋白类物质Ⅱ相对浓度最高,占DOM总量的37.51%~54.2%,其主要与生活污水排放有关;DOC浓度与芳香蛋白类物质Ⅰ、芳香蛋白类物质Ⅱ、溶解性微生物代谢产物及腐殖质类物质有较高相关性;TP浓度则与芳香蛋白类物质Ⅱ呈显著正相关性,与富里酸类物质和腐殖酸类物质显著相关。三维荧光光谱区域积分法可用于水体中DOM组成及污染物来源研究。

     

    Abstract: Based on the monitoring of water quality of Qixing wetland, the three-dimensional fluorescence spectroscopy combined with fluorescence regional integral (FRI) analysis were used to analyze the fluorescence characteristics of the dissolved organic matter (DOM) in the water body of Qixing wetland. The correlation of the DOM composition, humification degree and polluting sources and other water quality parameters were explored. The results showed that the Qixing wetland could purify pollutants from tributaries. The CODCr concentration in the effluent of the wetland met grade V standard (GB 3838-2002), and ammonia nitrogen and total phosphorus were still the main pollutants in the water. The mean value of fluorescence index (f450/500) was 1.82, indicating biological origin of the DOM. Humification index (rB,D) is overall low, indicating higher humification degree of wetland water and more serious organic pollution. The fluorescence spectra were divided into five components by fluorescence regional integration method. Aromatic protein II was the largest content which accounted for 37.51%-54.2% of total DOM and mainly related to sewage discharge. DOC significantly correlated with aromatic protein I, II, soluble microbial metabolites and humic substances. TP had significant correlation with aromatic protein substances II, fulvic acids and humic substances. Thus, three-dimensional fluorescence spectroscopy coupled with region integral method can be used in the research of water DOM composition and sources of contaminants.

     

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