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Air samples were collected, using a high-volume air sampler, at an urban site in Beijing from April 2014 to March 2015. The polychlorinated naphthalene (PCN) concentration in the atmosphere in each season was determined. The total PCN (total target tri- to octachloronaphthalene congeners) concentrations were 1.99-19.0 pg/m(3), and the mean was 7.20 pg/m(3). The PCN concentrations were higher in fall than summer, indicating that the concentrations varied significantly over time. The trichloronaphthalene homolog was the predominant PCN homolog in all four seasons. The PCN toxic equivalent (TEQ) concentrations were 0.42-6.89 fg/m(3), and the mean was 1.74 fg/m(3). The CN-66/67 and CN-73 congeners were the predominant contributors to the TEQ concentrations. The mean seasonal TEQ concentration decreased in the order fall (3.18 fg/m(3)) > winter (1.41 fg/m(3)) > summer (1.11 fg/m(3)) > spring (1.03 fg/m(3)). The TEQ concentrations and the PCN concentrations did not follow the same seasonal trends, but the highest TEQ and PCN concentrations were both found in fall. Correlation analysis, ratio analysis, and principal component analysis were used to investigate the sources of PCNs to the Beijing atmosphere. The results suggested that combustion processes may be the main sources of PCNs to the Beijing atmosphere.

The concentrations and patterns of polychlorinated naphthalenes (PCNs) were determined in surface sediment samples from Wuxi, Suzhou, and Nantong, in the Yangtze River Delta (East China), which has become urbanized rapidly. The total PCN (tri- to octachlorinated naphthalenes) concentrations in the samples from Wuxi, Suzhou, and Nantong were 0.89-40, 2.8-4600, and 0.60-34 ng/gdry weight, respectively. Unexpectedly high PCN concentrations were found in four of the sediment samples. The PCN concentrations were much higher in the samples from the Beijing-Hangzhou Grand Canal than in the samples from the Yangtze River. The toxic equivalent (TEQ) concentrations (determined from the concentrations of the "dioxin-like" PCNs) ranged from 1.45×10(-7) to 2.16 ng TEQ/g, and the congeners CN-66/67 and CN-73 were the predominant contributors to the TEQs. Independent samples t-tests were performed, and no significant differences were found between the PCN concentrations in the samples from the metropolitan area and the development zone when the four development-zone samples that contained very high PCN concentrations were excluded. The PCN profiles were dominated by the hexa- to octachlorinated naphthalene homologs. The CN-66/67 to CN-71/72 and CN-66 to CN-67 concentration ratios were used to identify specific PCN sources. Emissions from chemical and other industrial plants were found to have strongly influenced the PCN concentrations in sediment in the study area.

The formation of unintentionally produced persistent organic pollutants (POPs) may occur during various chlorination processes. In this study, emissions of unintentionally produced POPs during the methanol-based production of chlorinated methanes were investigated. High concentrations of highly chlorinated compounds such as decachlorobiphenyl, octachloronaphthalene, octachlorostyrene, hexachlorobutadiene, hexachlorocyclopentadiene, hexachlorobenzene, and pentachlorobenzene were found in the carbon tetrachloride byproduct of the methanol-based production of chlorinated methanes. The total emission amounts of hexachlorocyclopentadiene, hexachlorobutadiene, polychlorinated benzenes, polychlorinated naphthalenes, octachlorostyrene, and polychlorinated biphenyls released during the production of chlorinated methanes in China in 2010 were estimated to be 10 080, 7350, 5210, 427, 212, and 167 kg, respectively. Moreover, polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) were formed unintentionally during chlorinated methanes production, the emission factor for PCDDs/DFs was 364 μg toxic equivalency quotient (TEQ) t−1 product for residues, which should be added into the UNEP toolkit for updating. It was worth noting that a high overall toxic equivalency quotient from polychlorinated naphthalenes and PCDDs/DFs was generated from the chlorinated methanes production in China in 2010. The values reached 563 and 32.8 g TEQ, respectively. The results of the study indicate that more research and improved management systems are needed to ensure that the methanol-based production of chlorinated methanes can be achieved safely.