河北省夏季降雨溶解性有机物光谱特征的空间分布、来源解析及氮素响应

溶解性有机物(DOM)是大气环境有机物的重要组成部分,为了探究大气环境中DOM的演变特征,结合紫外-可见吸收光谱和三维荧光光谱对河北省夏季降雨雨水DOM的组分和光谱特征进行解析和研究.结果表明,该时期雨水DOM的分子量存在显著差异,北部地区要显著低于中部和南部地区(P <0.05);平行因子法解析出2种类腐殖质组分(C1和C4),1种类蛋白组分(C2)和1种富里酸组分(C3),组分C2与组分C3和C4呈现显著正相关(P <0.001),可能具有相似的来源;平行因子法中类蛋白组分(C2)占主体、其均值达到40.59%,与此同时各组分的荧光强度和相对丰度空间差异不显著(P> 0.05)、城乡间差异显著(P <0.05);荧光区域积分得到的各组分呈现出空间差异不显著(P> 0.05),城乡差异显著的特征(P <0.05);荧光区域积分得到的DOM类蛋白物质占主体(61.59%～89.01%),与平行因子法的结果相一致.与此同时,冗余分析(RDA)显示雨水中总氮、硝氮和氨氮是影响雨水DOM组成分布的主要水质参数;三维荧光光谱指数分布呈现出显著的城乡差异,高F...

Spatial Distribution Characteristics of the Spectrum, Source Analysis, and Nitrogen Response of Dissolved Organic Matter in Summer Rainfall in the Hebei Province

Dissolved organic matter(DOM) is an important component of the organic matter in the environment. This study explored the characteristics of DOM. The components and spectral characteristics of rainwater DOM were measured using Ultraviolet-visible absorption spectrum(UV-vis) and three-dimensional fluorescence spectrum in the Hebei province. The results showed significant differences for DOM molecular weight in the northern, central, and southern region; the DOM of the northern region exhibited the lowest molecular weight. Two humic-like(C1 and C4), one protein-like(C2) and one fulvic-like(C3) components were identified by parallel factor(PARAFAC) analysis. Component C2 had a significant positive correlation with components C3 and C4(P<0.001), which may have similar sources. The C2(protein-like substances) accounted for the major proportion of DOM with the average abundance 40.59%. The DOM components based on PARAFAC exhibited significantly difference between city and country regions without spatial difference, which was consistent with the result of fluorescence regional integration(FRI). The protein-like substances based on FRI were the main components, which accounted for 61.59%-89.01%. Redundancy analysis(RDA) showed that total nitrogen, nitrate, and ammonia were the main environmental factors determining the distribution of DOM. Spectral indices presented a significant difference between city and country regions. High fluorescence(FI) and biological(BIX) and low humification(HIX) values showed that summer rain exhibited the strong autochthonous and low humification characteristics, and country region have stronger autochthonous characteristics than city region. The regression analysis demonstrates that the prediction accuracy of rainwater quality parameters in city region is high. From all the results, rainwater DOM, showing strong autogenous characteristics, exhibited significant differences between city and country regions without spatial difference in Hebei. Meanwhile, it can also provide technical support for rainwater nitrogen concentration prediction based on DOM components.