Sewage sludge adsorbs a large amount of harmful organic pollutants, particularly the persistent and hydrophobic polyhalogenated compounds (PHCs). PHCs have been subjected to biological and chemical oxidation treatments during wastewater treatment processes; however, the species and concentrations of their transformation products (TPs) in sludge remain unknown, and the transformation pathways are unclear. In this study, 234 TPs of PHCs, including 77 TPs of chlorinated paraffins (CPs-TPs), 102 TPs of organochlorine pesticides (OCPs-TPs), 45 TPs of dechlorane plus (DPs-TPs), and 10 TPs of brominated flame retardants (BFRs-TPs), were identified in sludge through PhPCl-enhanced ionization coupled with ultra-performance liquid chromatography–Orbitrap–mass spectrometry. Based on the chemical structures of the identified TPs, we identified three major transformation pathways: dehalogenation-hydroxylation, carbon chain decomposition, and desulfurization. Approximately 97 TPs were newly discovered through the pathways. Carbon chain decomposition products of OCPs and DPs were detected for the first time at relatively high abundances. More hydroxylation products of DPs and hexabromocyclododecane (HBCD) and multi-dehalogenation products of heptachlor, toxaphene, DPs and HBCDs were detected at relative intensities higher than those of the known TPs. The oxidation treatment of sludge achieved up to 13 %–94 % of PHCs to be removed, with dehalogenation-hydroxylation as the main transformation pathway. Advanced treatment technologies are needed for degradation of both PHCs and their TPs.

中文翻译：

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鉴定约 200 种多卤化合物的转化产物，以表征其在污泥中的转化途径


污水污泥吸附大量有害有机污染物，特别是持久性和疏水性多卤化合物（PHC）。 PHC 在废水处理过程中经过生物和化学氧化处理；然而，污泥中其转化产物（TP）的种类和浓度仍然未知，转化途径也不清楚。本研究中，PHCs 234 TPs，其中氯化石蜡（CPs-TPs）77 TPs、有机氯农药（OCPs-TPs）102 TPs、二氯乙烷加（DPs-TPs）45 TPs、溴化阻燃剂 10 TPs (BFRs-TPs)，通过 PhPCl 增强电离结合超高效液相色谱-Orbitrap-质谱法在污泥中进行鉴定。根据已确定的TP的化学结构，我们确定了三种主要的转化途径：脱卤-羟基化、碳链分解和脱硫。通过这些途径新发现了大约 97 个 TP。首次以相对较高的丰度检测到 OCP 和 DP 的碳链分解产物。检测到更多的 DPs 和六溴环十二烷 (HBCD) 羟基化产物以及七氯、毒杀芬、DPs 和 HBCDs 的多重脱卤产物，其相对强度高于已知 TPs。污泥氧化处理可去除13%~94%的PHCs，以脱卤-羟基化为主要转化途径。降解 PHC 及其 TP 需要先进的处理技术。