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

Abstract

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 ...

Characterization of polychlorinated dibenzo- p -dioxins and dibenzofurans, dioxin-like polychlorinated biphenyls, and polychlorinated naphthalenes in the environment surrounding secondary copper and aluminum metallurgical facilities in China

“…Although there were also large variation in the UP-POPs concentrations in the stack gases emitted from different plants (Hu et al, 2013a), we found that there were clear correlations between the ambient air and the stack gas concentrations of the PCDD/Fs, dl-PCBs and PCNs among the five investigated plants, respectively (Fig. 1).…”

“…We have previously reported the details of the methods used to analyze the samples for UP-POPs (Guo et al, 2008;Hu et al, 2013a). Briefly, the samples were spiked with known amounts of 13 C 12 -labeled PCDD/Fs, 13 C 12 -labeled PCBs, and 13 C 10 -labeled PCNs, for use as internal standards (Table S1), then they were Soxhlet extracted with toluene for approximately 24 h. Each sample extract was concentrated and then subjected to a series of adsorption chromatography clean-up procedures, which were an acidified silica gel column, a multilayer silica gel column (filled, from top to bottom, with anhydrous sodium sulfate, 1 g activated silica gel, 8 g silica gel containing 44% (w/w) of H 2 SO 4 , 1 g activated silica gel, 5 g silica gel containing 33% (w/w) of 1 M NaOH, 1 g activated silica gel, 2 g of silica gel containing 10% (w/w) of AgNO 3 , and 1 g activated silica gel), and a basic alumina column.…”

“…The stack gas emitted from the investigated plants was also collected and analyzed during ambient air sampling period, which we have previously reported (Hu et al, 2013a). The concentrations and homolog profiles of the UP-POPs in the ambient air were compared with those in the stack gases emitted from the same plants to determine if UP-POPs emissions from each plant affected their surrounding environment.…”

“…Air samples were collected from downwind of each plant, and, at the same time, air samples were collected from upwind of each plant, to act as control samples. Additionally, the stack gas emitted from these investigated plants was also collected and analyzed during ambient air sampling period, which we have previously reported (Hu et al, 2013a). The concentrations and homolog profiles of the UP-POPs in the ambient air were compared with those found in stack gases emitted from the same plants.…”

Formation and potential mechanisms of polychlorinated dibenzo-p-dioxins and dibenzofurans on fly ash from a secondary copper smelting process

“…The release of PCDD/Fs from a metal smelter might cause increased risks to workers in the metallurgical industry (Hu et al 2013a). The exposure of metallurgical smelting workers to PCDD/Fs has been assessed in several studies (Abballe et al 2013;Hu et al 2013a; Lee et al 2009;Shih et al 2008).…”