Ertunç Tanya, Hartlieb Nicola, Berns Anne, Klein Werner, Schaeffer Andreas
Department of Biology V-Environmental Chemistry, University of Technology Aachen, Germany.
Chemosphere. 2002 Nov;49(6):597-604. doi: 10.1016/s0045-6535(02)00333-8.
14C-labelled simazine was composted together with biowaste on a pilot (m3) scale. The herbicide was quickly bound to the compost matrix. By aqueous extraction of 29 and 200 days old compost (equivalent to thermophilic and mesophilic phase of composting) only 4.2% and 3.1% respectively of the radioactivity in the compost samples could be extracted with water. Analysis of the extracts using high-performance size exclusion chromatography (HPSEC) revealed that the dissolved organic matter (DOM) had molecular weights ranging between 2 and 28 kDa. The amount of DOM-associated radioactivity increased from 53% (day 29) to 65% (day 200) of total extractable radioactivity. The type of binding of the 14C-labelled residues and the DOM was elucidated by silylation of humic matter and subsequent HPSEC. The data demonstrated that besides polar metabolites also intact simazine was bound to the DOM. A distinct shift from rather weak interactions to strong covalent linkages of simazine and its metabolites with increasing age of the compost was observed. The results showed that only low amounts of free simazine and its degradates can be extracted with water. We concluded that the shift towards stable covalent linkages is equivalent to a detoxification of the contaminant in aged compost. Consequently, the use of the analysed compost in its mature stage should not pose an environmental risk to the groundwater or the subsoil.
将14C标记的西玛津与生物废弃物在中试（立方米）规模下进行堆肥处理。该除草剂迅速与堆肥基质结合。通过对29天和200天龄的堆肥（分别相当于堆肥的嗜热阶段和中温阶段）进行水萃取，堆肥样品中分别仅有4.2%和3.1%的放射性能够被水萃取出来。使用高效尺寸排阻色谱法（HPSEC）对萃取物进行分析显示，溶解有机物（DOM）的分子量在2至28 kDa之间。与DOM相关的放射性量从总可萃取放射性的53%（第29天）增加到65%（第200天）。通过腐殖质的硅烷化及随后的HPSEC阐明了14C标记残留物与DOM的结合类型。数据表明，除了极性代谢物外，完整的西玛津也与DOM结合。随着堆肥龄期的增加，观察到西玛津及其代谢物从相当弱的相互作用向强共价键明显转变。结果表明，用水只能萃取出少量游离的西玛津及其降解产物。我们得出结论，向稳定共价键的转变等同于老化堆肥中污染物的解毒。因此，在成熟阶段使用分析过的堆肥对地下水或底土不应构成环境风险。
