Atmospheric Emission of PCDD/Fs, PCBs, Hexachlorobenzene, and Pentachlorobenzene from the Coking Industry

Abstract

The coking process is considered to be a potential source of unintentionally produced persistent organic pollutants (UP-POPs). However, intensive studies on the emission of UP-POPs from the coking industry are still very scarce. Emission of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (dl-PCBs), hexachlorobenzene (HxCBz), and pentachlorobenzene (PeCBz) covered under the Stockholm Convention were investigated for the coking process in this study. Stack gases from some typical coke plants in China were collected and analyzed to estimate the emission of UP-POPs from the coking industry. Emission factors of 28.9 ng WHO-TEQ tonne -1 for PCDD/Fs, 1.7 ng WHO-TEQ tonne -1 for dlPCBs, 596 ng tonne -1 for HxCBz, and 680 ng tonne -1 for PeCBz were derived based on the investigated data. The annual emissions from the global coking industry were estimated to be 15.8 g WHO-TEQ for PCDD/Fs, 0.93 g WHO-TEQ for dl-PCBs, 333 g for HxCBz, and 379 g for PeCBz, respectively (reference year 2007). According to the distribution of PCDD/Fs, we argued for the de novo synthesis to be the major pathway of PCDD/F formation. With regard to the characteristics of dl-PCBs, the most abundant congener was CB-118, and the most dominant contributor to the total WHO-TEQ of dl-PCBs was CB-126. IntroductionPersistent organic pollutants (POPs) are extremely harmful to human health and the environment because of their high toxicity, persistence in the environment, and bioaccumulation through the food web. Once released into the environment, they can be transported and distributed on a global scale by the grasshopper effect and global fractionation (1,2). Minimizing environmental exposure to POPs is an important public goal for environmental protection, also with respect to sustainable development. As it is very difficult to eliminate POPs by photodegradation, chemical degradation, or biodegradation under environmental conditions due to their high stability and persistence (3), controlling and regulating the emission of unintentionally produced POPs (UP-POPs) from key sources is one of the most effective measures for protecting our environment and human health from .Evaluating the emissions of UP-POPs from sources is important for applying the best available technology/best environmental practice (BAT/BEP) to priority sources and developing a POP inventory. Many sources for the emission of UP-POPs have been identified and quantified (7,8), and the effects of various parameters on the formation of UPPOPs have been demonstrated in many studies (9-13). Sources of POPs and their relative importance have changed substantially over the past several decades. Municipal waste incineration was previously a major contributor of UP-POPs to the environment, but following the implementation of various regulations, and improvements in combustion technology and emission cleaning techniques, this is now generally considered to have a lower contribution to the total emissions to air. Thus, some other potential sources ...

Characterization of polychlorinated naphthalenes in stack gas emissions from waste incinerators

“…In other incinerators, the most dominant toxic congeners were CN66/77 and CN73 owing to their relatively high RPFs compared with other PCN congeners. The toxic profiles of PCNs in this study were similar to that of the coking industries and secondary nonferrous metallurgical facilities (Liu et al 2009;Ba et al 2010). In these studies, CN1, CN2, CN66/ 77, and CN73 were also the main toxic contributors.…”

“…The dioxin-like toxicity of PCNs has been investigated in previous studies (Hanberg et al 1990;Blankenship et al 2000;Villeneuve et al 2000). The relative potency factors (RPFs) of individual PCN congeners to 2378-TCDD estimated in these studies have been used to evaluate the toxicity of PCNs (Noma et al 2004;Guo et al 2008;Liu et al 2009). In this study, the TEQs of PCNs were defined by the sum of the products of the concentration of each congener multiplied by its RPF reported by Noma et al (ESM Table S1).…”

Occupational Exposure to Polychlorinated Dibenzo-p-dioxins and Dibenzofurans, Dioxin-like Polychlorinated Biphenyls, and Polychlorinated Naphthalenes in Workplaces of Secondary Nonferrous Metallurgical Facilities in China

“…21 −23 The relative potency factors (RPFs) of individual PCN congeners to 2378-TCDD estimated in these studies have been used to evaluate the toxicity of PCNs. 14,24,25 In this study, the TEQs of PCNs were defined by the sum of the products of the concentration of each congener multiplied by its RPF reported by Noma et al 24 (Table S2 of the Supporting Information). The dioxin-like PCNs (dl-PCNs) were defined as those congeners whose toxic equivalent factors have been calculated (Table S2 of the Supporting Information).…”

A preliminary investigation of unintentional POP emissions from thermal wire reclamation at industrial scrap metal recycling parks in China

“…PCB-118 is generally considered to be the dominant congener among the dl-PCBs for many thermal related sources [38][39][40][41]. The concentrations of the dl-PCB congeners are shown in Fig.…”