Unintentional formed PCDDs, PCDFs, and DL-PCBs as impurities in Chinese pentachloronitrobenzene products.

Pentachloronitrobenzene (PCNB) products have been reported to contain relatively high levels of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) as impurities. No data was available for Chinese PCNB products which are still produced and used in China. Therefore, we analysed Chinese PCNB products, including two raw pesticides and three formulations available on the market. In all samples, PCDDs, PCDFs, and dioxin-like polychlorinated biphenyls (DL-PCBs) were detected at levels exceeding Japanese regulation limits. The concentrations of PCDDs and PCDFs (0.16 to 0.93 ng TEQ g(-1)) were lower than the PCNB formulations measured from the Australian market (3.9 ng TEQ g(-1)). However, the Toxic Equivalent (TEQ) contribution from DL-PCBs (0.7 to 2.5 ng TEQ g(-1)) to total TEQ was higher compared to PCDDs and PCDFs. This discovery demonstrated that it is necessary to consider the DL-PCBs impurity in organochlorine pesticides and other organochlorine chemicals in particular chlorinated aromatic compounds for adequate risk assessment. In addition to DL-PCBs, other unintentionally POPs-hexachlorobenzene (HCB) (3.7 to 52 ng g(-1)) and pentachlorobenzene (PeCBz) (0.04 to 0.3 ng g(-1)) which are listed in the Stockholm Convention-were detected in the PCNB samples. The PCNB production steps were assessed for their unintentional POPs formation potential. Thermolysis of the aromatic compounds using iron chloride (FeCl3) as catalyst is suggested as relevant production step for (DL-)PCBs formation. Since the levels in the formulated PCNB recalculated to active ingredient were higher compared to the raw pesticide, the formulation process (e.g., milling) may also have had an influence on additional PCDD/Fs and PCBs formation.

Congener-specific analysis of polychlorinated naphthalenes (PCNs) in the major Chinese technical PCB formulation from a stored Chinese electrical capacitor.

Impurity of polychlorinated naphthalenes (PCNs) in commercial polychlorinated biphenyl (PCB) formulations has been recognized as a relevant source of PCNs in the environment. Congener-specific analysis of most main PCB formulations has been accomplished previously, excluding the Chinese product. The insulating oil in a stored Chinese electric capacitor containing the major Chinese technical formulation "PCB3" was sampled and tested by isotope dilution technology using high-resolution gas chromatography coupled to high-resolution mass spectrometry (HRGC/HRMS). The detected concentration of PCNs in the Chinese PCB oil sample was 1,307.5 µg/g and therefore significantly higher than that reported in PCB formulations from other countries, as well as that in the transformer oil (ASKAREL Nr 1740) additionally tested in the present study for comparison. Based on the measurement, the total amount of PCNs in Chinese PCB3 oil is estimated to be 7.8 t, which would mean only 0.005 % of global production of PCNs of 150,000 t. The homolog profile is similar to those of PCN in Aroclor 1262 and Clophen A40, where the contributions from hexa-CNs and hepta-CNs are predominant and accounted for similar proportions. The Toxic Equivalent Quantity (TEQ) concentration of dioxin-like PCN congeners is 0.47 µg TEQ/g, with the dominant contributors of CN-73 and CN-66/67. This TEQ content from PCN is higher than that in most other PCB formulations with the exemption of the Russian Sovol formulation. The total TEQ in the historic 6,000 t of the Chinese PCB3 formulation is estimated to be 2.8 kg TEQ.

Characterizing the emission of chlorinated/brominated dibenzo-p-dioxins and furans from low-temperature thermal processing of waste printed circuit board.

This study focuses primarily on the inventory of PCDD/Fs and PBDD/Fs associated with the low-temperature thermal processing of scrap printed circuit boards (PCBs). Twelve 2,3,7,8-substituted PBDD/Fs congeners were found in various sample outputs, with a total content of 60,000 ng TEQ/kg at 250°C under air atmosphere. A rapid increase of PBDD/Fs was produced with 160,000 ng TEQ/kg, at 275°C-about twice that under the N(2) atmosphere. At 275°C, the total contents of PCDD/Fs were only 170 and 770 ng TEQ/kg under an N(2) and air atmospheres respectively. The results reveal that a large contribution of PBDD/Fs emission may be expected from the dismantling or any other thermal processing of PCB scrap. PCDD/Fs, however, are formed and released into the environment in a variety of ways. Additional research is required to look for the causal factors that affect emissions.

Determination of PCBs, PCDDs and PCDFs in insulating oil samples from stored Chinese electrical capacitors by HRGC/HRMS.

Homologue and congener profiles of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in commercial PCBs formulations are key information for the source identification of PCBs contamination as well as for the risk assessment caused by potential exposure. The isotope dilution technology in combination with high resolution gas chromatography-high resolution mass spectrometry (HRGC/HRMS) has made the accurate determination of such profiles possible. So far, various commercial PCB formulations except Chinese products have been successfully determined. Two PCBs containing insulating oil samples from stored Chinese electrical capacitors have been determined with the same methodology for comparability. The total concentration PCBs in two oil samples were 790,000 µg g(-1) and 720,000 µg g(-1), respectively. TriCBs, TetraCBs, and DiCBs were found to be most abundant. Concentration of dioxins contamination in two samples is 650-670 ng TEQ g(-1), of which 69-71ngTEQg(-1) from PCDD/Fs with the predominant congeners of 1,2,7,8-TeCDF; 2,3,7,8-TeCDF; 2,3,4,7,8-PeCDF and 1,2,3,7,8-PeCDF. The contributions of DL-PCBs in total TEQ in both samples were more than 85%. The dioxin-like toxicity in insulating oils contained in electrical capacitors could be considered receive attention as an important dioxins source if such wastes are not managed in an environmentally sound manner.

Characterization and inventory of PCDD/Fs and PBDD/Fs emissions from the incineration of waste printed circuit board.

Many developing countries have not significantly changed their course with regard to electronic waste contamination, and they are still facing the specter of mountains of hazardous electronic waste, with serious consequences for both the environment and public health. An efficient and stable analytical method was developed to determine the inventory and emission factors of polybrominated dibenzo-p-dioxin and dibenzofurans (PBDD/Fs) and polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs) formed from the incineration of scrap printed circuit boards (PCBs). Both PBDD/Fs and PCDD/Fs have been found in all experimental sections with a maximum formation rate at temperatures between 250 and 400 °C. The amounts tended first to increase and then began to decrease as the temperature rose. When subjected to a heating temperature of 325 °C, the total content of twelve 2,3,7,8-substituted PBDD/Fs congeners (tetra- through octabromo-) gathered from three outputs was the largest, at 19 000, 160 000, and 57 ng TEQ/kg in solid, liquid, and gaseous fractions, respectively; the total content of seventeen 2,3,7,8-substituted PCDD/Fs congeners (tetra- through octachloro-) was 820, 550, and 1.4 ng TEQ/kg. The formation of PCDD/Fs was remarkably less than that of PBDD/Fs because bromine concentrations considerably exceeded chlorine concentrations. The ingredients and conditions necessary to form PCDD/Fs or PBDD/Fs were definitely present, such as products of incomplete combustion, halogenides, an oxidizing atmosphere, and a catalyst-Cu salts being the most effective, significantly increasing the yields of PCDD/Fs and PBDD/Fs and decreasing the optimum temperature range.

HRGC/HRMS analysis of mirex in soil of Liyang and preliminary assessment of mirex pollution in China.

China is a country with the most severe termite damage in the world. Mirex is one of the two effective orgochlorine pesticides used in China for termite control. A high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) was employed for mirex analysis in soil samples from Liyang city, which once was an important mirex production base in China. The detected mirex levels in soil in Liyang were 2.9-4300pgg(-1)dw (dry weight), with the geometric mean 26.83pgg(-1)dw and the geometric standard deviation 5.02. The highest level occurred at the site near the Liyang Guanghua Chemical Factory. It implies the contribution of industrial activities to the mirex pollution in the surrounding environment. However, the factory only influenced very limited adjacent areas. A Level III fugacity model was developed to study the mirex pollution in Chinese provinces. The results show that the highest concentration occurred in Jiangxi Province, which has the largest consumption of mirex among Chinese provinces. On a regional scale, the calculated concentrations of mirex in the environment are generally so low that it indicates no harm to human and organisms. The total amount of mirex in the environment in China was estimated to be about 25.12tons, most of which exists in soil.