Congener-Specific Composition of Polychlorinated Naphthalenes, Coplanar PCBs, Dibenzo-p-dioxins, and Dibenzofurans in the Halowax Series

Liu

et al. 2013

Environ. Sci. Technol.

ABSTRACT:The concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (dl-PCBs), and polychlorinated naphthalenes (PCNs) were determined in workplace air from eight secondary nonferrous metal processing plants to investigate occupational exposure to these toxic compounds. The total estimated daily intakes of PCDD/Fs and dlPCBs for workers by inhalation in the workplace were in the range of 0.15−9.91 and 0.13−8.59 pg of WHO-TEQ/kg of body weight (bw) for moderate and light activities, respectively. The daily inhalation doses for workers in the workplaces of three investigated plants exceeded the tolerable daily intake recommended by the World Health Organization. These results indicate that the risk of occupational exposure to dioxins by inhalation in the workplace of plants investigated was considerably high. For PCNs, the daily inhalation doses for workers in the workplace were in the range of 0.005−4.46 and 0.004−3.87 pg of TEQ/kg of bw for moderate and light activities, respectively, which were lower than those of dioxins. To identify the source of PCDD/Fs, PCBs, and PCNs in workplace air, their homologue profiles were compared with those in stack gas from the plants investigated. It was found that significant dioxin contamination in workplace air was mainly attributed to the emission of fugitive gas from smelting furnaces during reclamation processes. ■ INTRODUCTIONSecondary metal smelters primarily engage in the recovery of nonferrous metals and alloys from new and used scrap and dross. Scrap metal and metal wastes may contain organic materials, such as plastics, paints, and solvents. 1 High emissions of unintentionally produced persistent organic pollutants (UPPOPs) have been determined in stack gas of secondary nonferrous metal processing plants, caused by the combustion of these impurities in the presence of various types of metals during reclamation processes. 2−6 During the secondary nonferrous metal smelting process, the smelting furnace door would be open for feeding raw material, mixing, and other necessary operations. Therefore, fugitive UP-POP emissions can be directly released into the workplace air during the process. Several studies have been conducted to investigate polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) concentrations in the workplace air of some industrial thermal processes, such as sinter plants, municipal solid waste incinerators (MSWIs), and secondary aluminum and copper smelters. 7−10 Moreover, the results of these studies suggested that there was significant PCDD/F contamination in the workplace air of the industrial thermal process plants investigated. Shih et al. 8 investigated PCDD/F levels in the workplace atmosphere of a sinter plant, and their results indicated that PCDD/F concentrations in workplace air (0.55− 2.14 pg of I-TEQ/m 3 ) were obviously higher than that of the outside ambient environment (0.07 pg of I-TEQ/m 3 ). In a secondary aluminum smelter, PCDD/F concentrations during operation were ...

Section: ■ Results and Discussionmentioning

confidence: 99%

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

Liu

et al. 2013

Environ. Sci. Technol.

“…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).…”

Section: Concentration Of Pcns Emitted From Waste Incinerators Investmentioning

confidence: 99%

Characterization of polychlorinated naphthalenes in stack gas emissions from waste incinerators

et al. 2012

Environ Sci Pollut Res

Nine typical waste incinerating plants were investigated for polychlorinated naphthalene (PCN) contents in their stack gas. The incinerators investigated include those used to incinerate municipal solid, aviation, medical, and hazardous wastes including those encountered in cement kilns. PCNs were qualified and quantified by isotope dilution high resolution gas chromatography-high resolution mass spectrometry techniques. An unexpectedly high concentration of PCNs (13,000 ngNm −3 ) was found in the stack gas emitted from one waste incinerator. The PCN concentrations ranged from 97.6 to 874 ngNm −3 in the other waste incinerators. The PCN profiles were dominated by lower chlorinated homologues, with mono-to tetra-CNs being the main homologues present. Furthermore, the relationships between PCNs and other unintentional persistent organic pollutants involving polychlorinated dibenzo-p-dioxins and dibenzofurans, polychlorinated biphenyls, hexachlorobenzene, and pentachlorobenzene were examined to ascertain the closeness or otherwise of their formation mechanisms. A good correlation was observed between ΣPCN (tetra-to octa-CN) and ΣPCDF (tetra-to octa-CDF) concentrations suggesting that a close relationship may exist between their formation mechanisms. The results would provide an improved understanding of PCN emissions from waste incinerators.

“…The WHO-TEF 2005 values reported by Van den Berg et al [18] were used to calculate the TEQs for the PCDD/Fs and dlPCBs. The TEQs for the dioxin like PCNs (dl-PCNs) and HxCBz were calculated based on the relative potency factors (RPFs) reported by Noma et al [19] and van Birgelen [20], respectively. Table 2 shows that the average WHO-TEQ values of PCDD/Fs measured in the flue gas samples at P1 and P2 in this study were 47.1 and 11.…”

Section: Concentrations Of Unintentional Pops Emitted From Thermal Wimentioning

confidence: 99%

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

Nie

Journal of Hazardous Materials

Liu

et al. 2012

a b s t r a c tThermal wire reclamation is considered to be a potential source of unintentional persistent organic pollutants (unintentional POPs). In this study, unintentional POP concentrations, including PCDD/Fs, dioxin like PCBs (dl-PCBs), polychlorinated naphthalenes (PCNs), hexachlorobenzene (HxCBz) and pentachlorobenzene (PeCBz), were quantified in flue gas and residual ash emissions from thermal wire reclamation at scrap metal dismantling parks in Zhejiang Province, China. The total average TEQ emissions of the investigated unintentional POPs from flue gas and residual ash in two typical scrap metal recycling plants ranged from 13.1 to 48.3 ng TEQ N m −3 and 0.08 to 2.8 ng TEQ g −1 , respectively. The dominant PCDD/F congeners were OCDD, 1,2,3,4,6,7,8-HpCDD, OCDF and 1,2,3,4,6,7,8-HpCDF, while PCB-126 and PCB-169 were the main contributors to the toxicity of the dl-PCBs. There were clear differences in the distribution dl-PCBs congeners contributing to the TEQ concentrations in the flue gas samples from the two plants. The PCN TEQs were dominated by PCN-66/67 and PCN-73. Although thermal wire reclamation in incinerators has been proposed as an alternative to open burning, there are still considerable environmental risks associated with regulated incinerators, and unintentional POP emissions from thermal wire reclamation sites need to be controlled by local government agencies.