Department of Environmental Geosciences, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria.
Sci Total Environ. 2011 Feb 1;409(5):905-19. doi: 10.1016/j.scitotenv.2010.11.009. Epub 2010 Dec 18.
Different classes of organic matter (OM) have been systematically investigated in sediments and suspended particulate matter (SPM) along the Danube River in order to understand causes of compositional changes. Analytical pyrolysis revealed the dominance of natural organic matter (NOM) in most of the samples. The predominance of aquatic biomass is evident mainly from the abundance of organonitrogen compounds and phenol distributions. As the river enters a forested gorge, the terrestrial component of the NOM in sediments is more significant. This is reflected in abundant methoxyphenols and a very high carbon preference index. SPM sample from a tributary shows a unique geochemical signature. It contains abundant carboxylic acids, amines, isoprenoids in the pyrolyzate, and is dominated by phytol and 24-methyl-cholesta-5,24(28)-dien-3β-ol in the extract, produced by a diatom bloom. Wax esters with a relatively high proportion of short, methyl-branched alkyl-chains appear together with abundant phytadienes and n-C(17) alkane in some samples, suggesting a microbial origin. Anthropogenic OM from runoff and atmospheric deposition was evident from a minor input of polycyclic aromatic hydrocarbons (PAHs) originating from mixed combustion sources. Multivariate analysis using PAH data led us to define simple molecular ratios to distinguish the PAH composition in sand and silty sediments. The newly defined ratios are the alkylated phenanthrenes and anthracenes ratio (APA; C(1)-C(3)/C(0)-C(3) phenanthrenes and anthracenes) and the PAH ring number ratio (RN; 5-6 ring parent PAHs/all parent PAHs). This demonstrates that alkylated, as well as 5-6 ring PAHs are better preserved in the finer than in coarser grained sediments. A ubiquitous, but minor input of petroleum-related contamination with a uniform composition was evident in all samples as revealed by the analysis of petroleum biomarkers. This study demonstrates that the investigation of different classes of riverine OM requires a detailed molecular analysis, applying a series of analytical techniques and adequate statistical data treatment.
为了了解组成变化的原因，对多瑙河沉积物和悬浮颗粒物（SPM）中的不同类有机物质（OM）进行了系统研究。分析性热解揭示了大多数样品中天然有机物质（NOM）的优势。水生生物量的优势主要从有机氮化合物和苯酚分布的丰富程度上表现出来。随着河流进入森林峡谷，沉积物中 NOM 的陆地成分变得更加显著。这反映在丰富的甲氧基苯酚和非常高的碳优先指数上。支流的 SPM 样品显示出独特的地球化学特征。它在热解产物中含有丰富的羧酸、胺和异戊二烯，在提取物中以植醇和 24-甲基-胆甾-5,24（28）-二烯-3β-醇为主，由硅藻大量繁殖产生。蜡酯与相对较高比例的短链、甲基支链烷基链一起出现，与一些样品中的大量植二烯和正 C（17）烷一起，表明其具有微生物起源。来自径流和大气沉降的人为 OM 从混合燃烧源产生的少量多环芳烃（PAHs）输入中可以明显看出。使用 PAH 数据进行的多元分析使我们能够定义简单的分子比，以区分砂质和粉质沉积物中的 PAH 组成。新定义的比值是烷基化菲和蒽比值（APA；C（1）-C（3）/C（0）-C（3）菲和蒽）和 PAH 环数比值（RN；5-6 环母体 PAHs/所有母体 PAHs）。这表明，烷基化的以及 5-6 环 PAHs 在较细的颗粒中比在较粗的颗粒中保存得更好。所有样品中都存在普遍存在的、但含量较少的与石油相关的污染，其组成均匀，这是通过对石油生物标志物的分析揭示的。本研究表明，对不同类型的河流有机物质的研究需要详细的分子分析，应用一系列分析技术和适当的统计数据处理。
