基于UV-vis和EEMs解析白洋淀冬季冰封期间隙水DOM的光谱特征及来源

Spectral characteristics and sources of DOM in sediment interstitial water from Baiyangdian Lake in Xiong′an new area during the winter freezing period based on UV-Vis and EEMs

基于三维荧光光谱(EEMs)技术结合平行因子分析法(PARAFAC)以及紫外-可见光谱技术(UV-vis),对雄安新区-白洋淀冬季冰封期不同特征区域间隙水溶解性有机物(DOM)的光谱特征以及来源进行解析.结果表明:冬季冰封期白洋淀不同特征淀区间隙水DOM的相对浓度差异显著,养殖区的最高、旅游区的最低;冰封期白洋淀大部分区域间隙水DOM的E3/E4均大于3.5,说明DOM以低腐殖质成分为主;三维荧光通过PARAFAC解析出3种组分,分别为类酪氨酸(C1)、类色氨酸(C2)和陆源腐殖质(C3);对3个组分进行相关性分析,结果显示C1与C2之间的相关系数达到0.99(p<0.001);白洋淀各个特征区域间的DOM总荧光强度和各荧光组分相对丰度呈现显著的差异(p<0.05);DOM的总荧光强度以及各组分的荧光强度均呈现出唐河入淀口高的特征,C1+C2是DOM的主要成分呈现养殖区多、自然区少的特点,养殖区达到79.30%~92.04%,自然区达到26.60%~38.55%;冰封期白洋淀间隙水水体的DOM荧光指数FI为(2.58±0.23)>1.8,生物源指数(BIX)为1.20±0.25,表明白洋淀DOM来源于生物活动并且以自生源为主,与腐殖程度指标(HIX)的结果相吻合;a254与硝氮、溶解性总磷和A254/A204,a355与S350~400;a440与S275~295、S350~400、E2/E4、E2/E6和E4/E6,C1以及C2与Fn280,C3与硝氮和Fn355相关性很好(p<0.05).综上,通过对冬季冰封期白洋淀各个典型淀区间隙水水体DOM光谱特征进行研究,可以为分析白洋淀水体有机物污染特征和白洋淀的水质管理提供技术支持.

We analyzed both the spectral characteristics and sources of dissolved organic matter(DOM) in Baiyangdian Lake during the winter freezing period using excitation emission matrix(EEM) spectroscopy technology combined with parallel factor analysis(PARAFAC) and UV-vis spectra. Results showed that the DOM concentration exhibited significant differences(p<0.05) among different districts in Baiyangdian Lake;the breeding and tourist area values were found to be high and low, respectively. The changes of E3/E4 absorbance indicated that the DOM contained low humic and autochthonous characteristics. In addition, two protein-like substances(C1, C2) and one humic-like substance(C3) were identified by the PARAFAC model. A significant correlation coefficient(p<0.001) was exhibited in both C1 and C2. The total DOM fluorescence intensity and the fluorescence intensity of each component of relative abundance exhibited significant difference distributions(p<0.05) among the different districts of Baiyangdian Lake;the maximum value was located in Tanghe river sample. Moreover, the combined total of both C1 and C2 substances accounted for the proportional majority of the DOM;the breeding area accounted for 79.30% to 92.04%, while the natural area accounted for 26.60% to 38.55%. The DOM exhibited strong autochthonous component characteristics based on the values of the biological index(BIX), fluorescence index(FI), and humidity index(HIX). Moreover, based on correlation analysis of p<0.01 the a254 was found to be related to A254/A204, a355, and S350~400;the a440 to S275~295, S350~400, E2/E4, E2/E6, and E4/E6;the C1 and C2 substances to Fn280;and C3 substance to nitrate and Fn355. It is expected that our results could contribute to the further exploration and control of organic carbon pollution sources by the managers of Baiyangdian Lake in the future.