Abstract Chlorinated and brominated polycyclic aromatic hydrocarbons (ClPAHs and BrPAHs; XPAHs) are carcinogenic organic pollutants which are mainly produced and emitted from combustion processes. In some environmental matrices, XPAHs display similar toxic properties and even higher toxic equivalent quantities (TEQs) than dioxins. Understanding the sources and formation mechanisms of XPAHs is important for controlling their emissions and human exposure to these ubiquitous pollutants. Nevertheless, comprehensive knowledge on the sources, formation mechanisms, and environmental characteristics of XPAHs, which are considered as emerging persistent organic pollutants (POPs) is lacking. Here, we review and discuss the knowledge on the primary sources (i.e. formation mechanisms, levels, composition pattern, emission factors in combustion and other anthropogenic sources), and secondary formation (i.e. formation from reactions between emitted PAHs and halogens in environmental compartments). Congener profiles of XPAHs released from various anthropogenic sources are evaluated for their possible application as source tracers of XPAHs. Regarding the chlorination of PAHs, we suggest and discuss two possible mechanisms, which result in the production of different congeners under different processes. Finally, knowledge on environmental exposure to XPAHs is reviewed. Research needs with regard to formation, emission, analytical methods, environmental exposure and environmental risk assessment are outlined.

中文翻译：

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氯化和溴化多环芳烃：来源、形成机制和环境中的发生

摘要 氯化和溴化多环芳烃（ClPAHs和BrPAHs；XPAHs）是主要在燃烧过程中产生和排放的致癌有机污染物。在某些环境基质中，XPAH 显示出与二恶英相似的毒性，甚至更高的毒性当量 (TEQ)。了解 XPAH 的来源和形成机制对于控制它们的排放和人类对这些无处不在的污染物的暴露非常重要。然而，对于作为新兴持久性有机污染物 (POPs) 的 XPAHs 的来源、形成机制和环境特征缺乏全面的了解。在这里，我们回顾和讨论有关主要来源的知识（即形成机制、水平、组成模式、燃烧和其他人为来源中的排放因子）和二次形成（即由排放的 PAH 与环境隔间中的卤素之间的反应形成）。评估了从各种人为来源释放的 XPAH 的同系物谱，以了解它们作为 XPAH 源示踪剂的可能应用。关于多环芳烃的氯化，我们提出并讨论了两种可能的机制，这两种机制导致在不同过程中产生不同的同系物。最后，回顾了有关 XPAH 环境暴露的知识。概述了有关形成、排放、分析方法、环境暴露和环境风险评估的研究需求。评估了从各种人为来源释放的 XPAH 的同系物谱，以了解它们作为 XPAH 源示踪剂的可能应用。关于多环芳烃的氯化，我们提出并讨论了两种可能的机制，这两种机制导致在不同过程中产生不同的同系物。最后，回顾了有关 XPAH 环境暴露的知识。概述了有关形成、排放、分析方法、环境暴露和环境风险评估的研究需求。评估了从各种人为来源释放的 XPAH 的同系物谱，以了解它们作为 XPAH 源示踪剂的可能应用。关于多环芳烃的氯化，我们提出并讨论了两种可能的机制，这两种机制导致在不同过程中产生不同的同系物。最后，回顾了有关 XPAH 环境暴露的知识。概述了有关形成、排放、分析方法、环境暴露和环境风险评估的研究需求。回顾了有关 XPAH 环境暴露的知识。概述了有关形成、排放、分析方法、环境暴露和环境风险评估的研究需求。回顾了有关 XPAH 环境暴露的知识。概述了有关形成、排放、分析方法、环境暴露和环境风险评估的研究需求。