城市纳污河流有色溶解有机物时空演变特征

利用平行因子分析和主成分分析方法,结合紫外吸收光谱与三维荧光光谱技术,研究了典型城市纳污河流-河北洨河水体有色溶解有机物(CDOM)的来源及随季节和空间变化特征,探讨了水体CDOM与水质指标间关系.结果表明:洨河水体CDOM主要为新近微生物源产生,受人类活动影响较大.CDOM浓度在时间变化上表现为春夏(2、5月)低,而秋冬(8、11月)高,从上游至下游呈现先升高再降低变化特征.荧光鉴别出的4种组分:组分1(类富里酸),组分2(类腐殖酸)及组分3(类胡敏酸)为类腐殖质,组分4为类蛋白物质.不同季节各组分来源及分布存在差异,除夏季外其他季节水体类蛋白与类腐殖质来源相似,尤其与类胡敏酸组分;类蛋白组分在各季节分布变化显著,冬春含量相对较高.洨河水体荧光物质与氨氮、亚硝氮具有共同来源,其中类腐殖质对COD贡献较为明显.采用光谱分析法并结合平行因子、主成分分析及聚类分析方法可识别污染源空间分布,揭示河体CDOM随季节变化规律.

Space-time characteristics of chromophoric dissolved organic matter from typical polluted city river

Typical urban polluted city river-Hebei Xiao River water CDOM of the source, spatial and temporal distribution characteristics were studied by fluorescence excitation-emission matrix spectra (EEM), ultraviolet-visible (UV-vis) combine with parallel analysis (PARAFAC), principal component analysis (PCA), and the correlation of CDOM and water chemical indicators was investigated as well. The results showed that Xiao River water CDOM was mainly microbial-derived for rencent human emission of water. The concentration of CDOM was at higher level in fall (August) and winter (November), but low in the spring (February) and summer (May). Variation characteristics of space redered on first increase and then decreases from upstream to downstream. Four florescence components were identified, and component 1 (fulvic acid), component 2 (humic) and component 3 (humic acid) originated from humic-like substance, while component 4ascribed to protein-like materials. The components had difference source and distribution was variable and changed with time. In addition to summer the protein-like and humic-like components had similar sources, especially with the humic acid components. The concentration of protein-like was higher in spring and winter, but lower in the summer and autumn. In the Xiao River fluorescent substance had greatly contribution of ammonia and nitrite, and the humic-like had an important influence of chemical oxygen demand. The results demonstrated that, EEM and UV-vis spectra coupled with PARAFAC, PCA and cluster analysis can be used to analyze the seasonal variation of the CDOM and identify the spatial distribution of pollution in the Xiao River.