Naturally produced volatile and polar organohalogens in soils

目前对土壤中卤代有机化合物的自然（生物和非生物）形成和降解的了解非常有限。目前尚不清楚土壤是否以及在何种环境条件下可以作为这些化合物的汇或源。就大气丰度和环境意义而言，自然界中形成的最重要的卤代化合物无疑是气态卤代甲烷。最近，它已成为明显的，大多数大气中的CH 3Cl和CH 3Br有陆地而不是海洋的起源。除了单卤代有机卤素之外，多卤代化合物如挥发性（例如CH 2Cl 2、CHCl 3）和极性（例如卤代苯酚、卤代苯甲醚、卤代乙酸、卤代苯甲酸、卤代苯乙酸）化合物在陆地环境中产生。研究单位项目NAFOSA的中心假设是，大多数已知的陆地环境中的非生物卤化反应方案与自由基化学有关，这三种基本的氧化还原敏感土壤成分-有机物，铁和氧。卤化物参与这些土壤反应似乎是偶然的。为了解决卤化过程的热点，有必要量化生物过程与次生氧化矿物（Fe，Mn）的反应表面接触所提供的还原有机材料的反应周转数。虽然NAFOSA主要针对挥发性化合物，但NAVOPOS项目还打算揭开硬币的另一面：非生物降解过程中极性卤化化合物的识别和定量分析。

The present knowledge of the natural (biotic and abiotic) formation and degradation of halogenated organic compounds in soils is very limited. It is not clear whether, and under which environmental conditions soils can act as a sink or source of these compounds. In terms of atmospheric abundance and environmental significance the most important halogenated compounds formed in nature are undoubtedly the gaseous halomethanes. Recently it has become apparent that most atmospheric CH3Cl and CH3Br have a terrestrial rather than a marine origin. Besides monohalogenated organohalogens, polyhalogenated compounds such as volatile (e.g. CH2Cl2, CHCl3) and polar (e.g. halophenols, haloanisols, haloacetic acids, halobenzoic acids, halophenylacetic acids) compounds are produced in the terrestrial environment. The central hypothesis of the Research Unit project NAFOSA is that most of the known reaction schemes for the abiotic halogenation in the terrestrial environment are linked to radical chemistry by three essential redox-sensitive soil constituents - organic matter, iron, and oxygen. It seems to be by chance that halides are involved in these soil reactions. To address the hot spots of halogenation processes it is necessary to quantify the reaction turnover numbers of reduced organic material delivered by biotic processes in contact with reactive surfaces of secondary oxidic minerals (Fe, Mn). While NAFOSA is heading mainly for volatile compounds, the project NAVOPOS is additionally intending to unravel the flip side of the coin: Identification and quantitation analysis of polar halogenated compounds from abiotic degradation processes.