白塔堡河底泥DOM组成结构的荧光光谱与多元统计模型表征

Fluorescence spectra and multivariate statistical model characterization of DOM composition structure of Baitapu River sediment

利用三维荧光光谱,结合平行因子(PARAFAC)分析、层次聚类分析(HCA)和分类回归树(CART)模型,以东北典型城镇化河流——白塔堡河为研究对象,分别在该河的农村段、城镇段和城市段采集表层底泥样品,研究表层底泥中溶解性有机质(DOM)的荧光组分,分析荧光组分空间特征,识别DOM特征的关键因子,并辨识污染源。结果表明:白塔堡河底泥DOM中包含6个DOM荧光组分,即类富里酸(C1)、微生物代谢产物(C2)、类胡敏酸(C3)、类色氨酸(C4)、类酪氨酸(C5)、酚类物质(C6);白塔堡河城镇段DOM荧光物质浓度最高,城市段次之,农村段最低;白塔堡河农村段底泥DOM以内源为主,城镇段与城市段受陆源和内源物质的双重影响;白塔堡河底泥污染程度为城镇段>城市段>农村段,底泥DOM呈现出农村段、城镇段和城市段分异特征;类酪氨酸与类富里酸是识别底泥DOM特征的2个关键因子。

Three-dimensional excitation-emission matrix spectroscopy(EEMs),parallel factor(PARAFAC)analysis,and hierarchical clustering analysis(HCA)with classification and regression tree(CART)were applied for spectroscopic data to characterize fluorescent components of dissolved organic matter(DOM)in the surface sediment samples,which were collected in rural,urban and city sections of the Baitapu River,a typical urbanization river in Northeast China.The spatial characteristics of fluorescence components were analyzed,the key factors of DOM characteristics identified,and the pollution sources distinguished.The results showed that six DOM fluorescent components were extracted from DOM of Baitapu River sediment,which contained fulvic acid(C1),microbial metabolites(C2),humic acid(C3),tryptophan-like(C4),tyrosine-like(C5)and phenolic(C6)materials.The fluorescence concentration of DOM was the highest in the town section of the Baitapu River,followed by the city section and the lowest in the rural section.The DOM fractions in the rural section was dominated by autochthonous origins,while the DOM fractions in the town and urban sections by terrigenous and autochthonous substances.The pollution degree of bottom sediment of the Baitabu River was ordered as town section>urban section>rural section,and the bottom sediment DOM showed the differentiation characteristics of rural section,town section and urban section.C1 and C5 were two key factors to recognize the DOM characteristics of sediment.