筼筜湖CDOM的三维荧光光谱及其污染示踪研究

测定了2008年4～5月厦门筼筜湖52个CDOM样的三维荧光及吸收光谱,以探讨利用其光谱特征示踪高污染近海浅水湿地生物修复过程中有机污染程度的可行性。利用平行因子分析对三维荧光光谱进行解谱。结果表明,筼筜湖CDOM可识别出3类5个荧光组分,包括类腐殖质荧光组分C1(240,325/422 nm)和C5(260,380/474 nm)、类蛋白质荧光组分C2(225,275/350 nm)和C4(240,300/354 nm)以及有机污染组分C3(225/342 nm),其中C3可作为外来有机污染物输入的指纹特征。松柏湖干渠及污水处理厂排放口C3组分及DOC浓度很高,表明周边污水输入是筼筜湖有机污染的主要来源。类腐殖质荧光组分C1及吸收系数a(280)与COD之间、类蛋白质荧光组分C2与BOD₅之间均具有很好的线性相关关系,表明CDOM的光谱特性可很好地指示有机污染程度,对评价有机污染严重水域生物修复作用机理及效果有重要的参考价值。

Fluorescence Excitation-Emission Matrix Spectroscopy of CDOM from Yundang Lagoon and Its Indication for Organic Pollution

Fluorescence excitation-emission matrix spectroscopy (EEMs) combined with absorption spectroscopy were applied to study the optical properties of CDOM samples from highly-polluted Yundang Lagoon in Xiamen in order to demonstrate the feasibility of using these spectral properties as a tracer of the degree of organic pollution in similar polluted coastal waters. Surface water samples were collected from 13 stations 4 times during April and May, 2008. Parallel factor analysis (PARAFAC) model was used to resolve the EEMs of CDOM. Five separate fluorescent components were identified, including two humic-like components (C1: 240, 325/422 nm; C5: 260, 380/474 nm), two protein-like components (C2: 225, 275/350 nm; C4: 240, 300/354 nm) and one xenobiotic-like component (C3: 225/342 nm), which could be used as a good tracer for the input of the anthropogenic organic pollutants. The concentrations of component C3 and dissolved organic carbon (DOC) are much higher near the inlet of sewage discharge, demonstrating that the discharge of surrounding sewage is a major source of organic pollutants in Yundang Lagoon. CDOM absorption coefficient a(280) and the score of humic-like component C1 showed significant linear relationships with COD_Mn, and a strong positive correlation was also found between the score of protein-like component C2 and BOD5. This suggested that the optical properties of CDOM may provide a fast in-situ way to monitor the variation of the water quality in Yundang Lagoon and that of similar polluted coastal waters.