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Numerous reports have elucidated different statistical approaches to identify temporal trends in atmospheric persistent organic pollutant (POP) time series. However, the correlation of industrial activity with concentrations of atmospheric POPs in Japan has not yet been determined. Herein, a panel data analysis of a 16-year monitoring program (2003–2018) conducted by the Japanese Ministry of Environment was used to investigate a range of POPs in the atmosphere above Japan. This work focuses on polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), polybrominated diphenyl ethers (PBDEs), hexachlorobenzene (HCB), and pentachlorobenzene (PeCBz) collected each year at 53 sites across Japan. The panel analysis revealed that PCB, PCN, and PBDE concentrations were influenced by a combination of factors including year, industrial activity (municipal and industrial waste incinerators, cement kilns, steel industry, and secondary zinc production), population, temperature, and atmospheric boundary layer. However, HCB and PeCBz were not significantly affected by these factors. Industrial activity showed stronger positive correlations with all homologues of PCBs, PCNs, and PBDEs as compared to those demonstrated by population. Significant decreasing trends were identified for the atmospheric ∑ P B D E s (half-life t1/2 = 9.4 years), ∑ P C N s (t1/2 = 8.9 years), and ∑ P C B s (t1/2 = 13.5 years) concentrations, while HCB and PeCBz showed slightly increasing or steady levels. As a statistical tool, panel data analysis can contribute to the assessment of spatial and temporal trends of POPs at a national scale, while elucidating different behavioral responses to numerous environmental variables.

This study analyzed polyhalogenated compounds (PHCs) such as brominated flame retardants (BFRs) in indoor air and dust samples from two modern homes in Japan. Concentrations of polychlorinated biphenyls (PCBs) and 2,4,6-tribromophenol (2,4,6-TBP) in exhaust and indoor air of two houses were detected at 10(2)-10(3)pgm(-3) order, which were well above those in outdoor air. For dust samples, the detected polybrominated diphenyl ether (PBDE) and polybrominated dibenzo-p-dioxins/furan concentrations resembled values found in our past study. Interestingly, compared to PBDE concentrations, two orders of magnitude higher concentration (13000 ng g(-1)) was observed for hexabromocyclododecanes (HBCDs) in a dust sample from one house. Based on the calculation of air/dust partition ratio values (Kad), low Kad values (log Kad

Aimed to give a preliminary image of dioxin pollution in China, chemometric analysis was performed to determine background dioxin levels during the period 1994-2002 and potential emission sources. Using principal components analysis (PCA), the congener profiles of 71 sediment samples from rivers, lakes, and sea bays around China were compared with the congener profiles of various known or suspected industrial, residential, and municipal dioxin sources to determine whether the dioxin residues typically found in a broad range of potential environmental sources could explain the presence of these chemicals in China. It was found that the background dioxin levels of China were similar to those of lightly polluted samples from other countries during the period 1994-2002. Primary ferrous ore sintering and secondary lead and aluminum smelters were the major sources of dioxin emission in China. Chloranil and wastewater from chemical plants, sodium pentachlorophenate, and pulp bleaching were also important sources of dioxin emission. Open burning of e-waste as well as diesel-fueled and leaded gas-fueled vehicles were additional possible sources of dioxin. In contrast to other countries, in China, flue gases from incineration of municipal waste, hazardous waste, and medical waste might be minor sources of dioxin emission.

We used polybrominated diphenyl ether (PBDE) data in air at 38 sites across Japan (2009-2012), which were measured by the Japan Ministry of Environment (JMOE), to elucidate the time trend and seasonality of atmospheric PBDEs. In order to address few (7% for BDE-47) to many (63% for BDE-153 and 183) non-detect data, Tobit model, also called a censored regression model was used. The model revealed that the concentrations of PBDE congeners were influenced by a combination of year, temperature, rainfall rate, and population density. Greater declines were observed for BDE-47, -99, -153 and -183 (-21, -25, -17, -23%/year, p < 0.05) than for BDE-209 (-6%/year, p = 0.065). These trends were consistent with the estimated trends of penta-, octa- and deca-BDE contained in in-use products based on domestic demand for PBDEs in Japan and product lifespan. Seasonal patterns were opposite for light congeners (BDE-47 and -99), which increased with temperature, and heavy congeners (BDE-183, and -209), which decreased with temperature. Temperature-dependent emission (evaporation) for light congeners and temperature-independent emission (abrasion) for heavy congeners, coupled with seasonality of atmospheric boundary layer height, might explain these seasonal patterns. Human population density showed a positive correlation with all PBDE congener concentrations, whereas PBDEs showed negative correlation with rainfall rate.

Intake fractions (iFs) for emissions to air, water, and soil for 17 PCDDs/DFs and 12 Co-PCBs were calculated with a level III multimedia model and a food-chain exposure model in succession. The two integrated models were tested by comparing the predicted and measured concentrations in the environment and by comparing intakes through food. Measurement-based iFs were also calculated and compared with the model-based iFs. The air concentrations predicted by the fate model were close to the median of the observed concentrations, whereas the predicted soil and water concentrations were one-third to one-tenth the observed concentrations. This difference was large in case of PCDDs and Co-PCBs, which was explained by the past pollution such as commercial PCB products and PCDD impurities in chloronitrofen (CNP) and pentachlorophenol (PCP). For fish, the predicted and observed exposures agreed well each other. For meat and milk, the predicted exposures were about 10 times the observed exposures for PCDDs/DFs, whereas the predicted and observed values agreed well for Co-PCBs. When the model was modified to consider feeding of fish meal to livestock and geographic bias in feed-grass production, the predicted congener profile was comparable to the measured profile. The comparison also suggested that chickens should be modeled separately from other terrestrial livestock. The model-based iFs for air emission of OCDD and 2378-TCDD were 0.001% and 0.1%, respectively. The iFs of most Co-PCBs were higher than those of PCDDs/DFs. These iF differences suggest the importance of the fate factor in assessing emissions of the 29 congeners.

Television (TV) set components are highly flame resistant, with their added brominated compounds such as polybrominated diphenyl ethers (PBDEs). These compounds might be released indoors via dust, which presents a potential exposure pathway for humans in the home environment. In this study, we collected dust from inside TV sets and TV set component samples (parts of housing front cabinets, rear cabinets and circuit boards) of five sets used in Japan. We measured BFRs (i.e., PBDEs, tetrabromobisphenol A (TBBPA) and hexabromocyclododecanes (HBCDs)) and polybrominated dibenzo-p-dioxins/dibenzofurans (PBDD/DFs). Analytical results of the TV components showed that the concentrations of PBDEs, TBBPA and PBDFs (48,000 microg/g, 19,000 microg/g and 9600 ng/g as mean values, respectively) were all highest in the rear cabinets. The SigmaPBDD concentrations (460 ng/g as a mean value) detected were highest in the circuit board samples. The respective SigmaPBDE and SigmaPBDF concentrations in the dust samples were 67-500 microg/g (mean 300 microg/g) and 180-650 ng/g (mean 410 ng/g). Such concentrations were 2-3 orders of magnitude higher than those previously reported for house dust samples, which suggests that the brominated compounds are transferred from TV components into dust. Comparison of congener patterns of the brominated compounds in the dust identified the components as the source of these BFRs.

The Chinese Government ratified the Stockholm Convention on Persistent Organic Pollutants (POPs) on 25 June 2004. As a party to the Convention, China is preparing its National Implementation Plan (NIP), which must be finished and submitted to the Conference of the Parties before November 11, 2006. The emission inventory and strategy for reducing unintentionally formed products is a very complex and difficult part of the NIP. In this paper, we analyzed the potential sources of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in China and calculated their possible emissions. We included municipal solid waste incineration, hazardous and medical waste incineration, pulp bleaching, sodium pentachlorophenate production and usage, illegal electrical and electronic waste ("e-waste") recycling, and ferrous and non-ferrous metal production, and prepared a preliminary analysis of dioxin emissions in China. The results show that ferrous metal production (104.2-6648.3g TEQ), non-ferrous metal production (2.6-3389.8 g TEQ), and sodium pentachlorophenate production and usage (120-368.0 g TEQ) should be major potential sources of dioxins and furans. Moreover, municipal solid waste and hazardous and medical waste incineration (35.5 g TEQ) should also be considered high priority sources owing to a rapidly increasing incineration ratio anticipated for the near future.