Yuichi Horii

Isomer-specific analysis of chlorinated biphenyls, naphthalenes and dibenzofurans in Delor: polychlorinated biphenyl preparations from the former Czechoslovakia.

Technical polychlorinated byphenyl (PCB) preparations--Delors 103, 104, 105, and 106--produced in the former Czechoslovakia were analyzed for their chlorobiphenyl (CB), chloronaphthalene (PCN) and chlorinated dibenzofuran (PCDF) composition and content using high resolution gas chromatography-mass spectrometry techniques. The congener patterns of Delors 103, 104, 105, and 106 resembled Aroclors 1242, 1248, 1254, and 1260. Delors contained PCNs and PCDFs, as impurities, at microgram per gram concentrations. Concentrations of PCNs and PCDFs in Delors were greater than those found in the corresponding Aroclors. The potential for the emissions of PCNs and PCDFs from Delor was estimated to be 3680 and 860 kg, respectively. Non- and mono-ortho PCBs were the major contributors to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents in Delor mixtures.

Flux of perfluorinated chemicals through wet deposition in Japan, the United States, and several other countries.

The widespread distribution of perfluorinated chemicals (PFCs) in different environmental matrices has prompted concern about the sources, fate, and transport of these classes of chemicals. PFCs are present in the atmosphere, but only a few studies have investigated their occurrence in precipitation. In this study, concentrations of 20 PFCs, including C3-C5 short-chain PFCs, were quantified using HPLC-MS/MS in precipitation samples from Japan (n = 31), the United States (n = 12), China (n = 5), India (n = 2), and France (n = 2). Among the PFCs measured, perfluoropropanoic acid (PFPrA) was detected in all of the precipitation samples. Average total PFC concentrations ranged from 1.40 to 18.1 ng/L for the seven cities studied. The greatest total PFC concentrations were detected in Tsukuba, Japan, whereas the lowest concentrations were detected in Patna, India. PFPrA, perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA) were found to be the dominant PFCs in Japanese and U.S. precipitation samples. No observable seasonal trend was found in precipitation samples from two locations in Japan. Annual fluxes of PFCs were estimated for Japan and the U.S. and the evidence for precipitation as an effective scavenger of PFCs in the atmosphere is reported.

Polybrominated diphenyl ethers, polychlorinated naphthalenes and polycyclic musks in human fat from Italy: Comparison to polychlorinated biphenyls and organochlorine pesticides

Prior to this study, reports of occurrence of polycyclic musks and polychlorinated naphthalenes (PCNs) in human tissues from Italy were not available. In this study, concentrations of PCNs and polycyclic musks were determined in human adipose tissue from Italy collected during 2005-2006; for comparison, legacy organohalogen pollutants such as organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) were determined. SigmaPCN concentrations ranged from 0.5 to 14 ng/g lipid wt (lw). Polycyclic musks such as HHCB and AHTN were found in 92% and 83% of the human samples, respectively. Concentrations of PBDEs in Italian adipose tissue ranged between 3.2 and 35.6 ng/g lw.

Environmental analysis of chlorinated and brominated polycyclic aromatic hydrocarbons by comprehensive two-dimensional gas chromatography coupled to high-resolution time-of-flight mass spectrometry

A method for the analysis of chlorinated and brominated polycyclic aromatic hydrocarbon (Cl-/Br-PAHs) congeners in environmental samples, such as a soil extract, by comprehensive two-dimensional gas chromatography coupled to a high resolution time-of-flight mass spectrometry (GC×GC-HRTOF-MS) is described. The GC×GC-HRTOF-MS method allowed highly selective group type analysis in the two-dimensional (2D) mass chromatograms with a very narrow mass window (e.g. 0.02Da), accurate mass measurements for the full mass range (m/z 35-600) in GC×GC mode, and the calculation of the elemental composition for the detected Cl-/Br-PAH congeners in the real-world sample. Thirty Cl-/Br-PAHs including higher chlorinated 10 PAHs (e.g. penta, hexa and hepta substitution) and ClBr-PAHs (without analytical standards) were identified with high probability in the soil extract. To our knowledge, highly chlorinated PAHs, such as C(14)H(3)Cl(7) and C(16)H(3)Cl(7), and ClBr-PAHs, such as C(14)H(7)Cl(2)Br and C(16)H(8)ClBr, were found in the environmental samples for the first time. Other organohalogen compounds; e.g. polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), and polychlorinated dibenzofurans (PCDFs) were also detected. This technique provides exhaustive analysis and powerful identification for the unknown and unconfirmed Cl-/Br-PAH congeners in environmental samples.

Polychlorinated naphthalene contamination of some recently manufactured industrial products and commercial goods in Japan

Abstract A follow-up case study was performed after two incidents of recent illegal import and use in Japan both of technical PCNs mixture and contaminated with those compounds an industrial raw material. In case 1, above 18 tons of PCNs mixture, resembling Halowax 1001, which is a technical PCNs formulation, were imported from the United Kingdom. An illegally imported PCNs mixture was used for manufacture of a wide spectrum of industrial materials and commercial goods including sealants, putty, shock absorbing materials, adhesive materials, insulating materials and rubber belts. About 1.3 tons of PCNs contained in the Neoprene FB manufactured reached domestic market and 9.3 tons could reach other markets. In case 2, which became known in 2001, the Japanese company imported from Canada 54 tons of PCNs contaminated raw rubber material for industrial use. In weathering test (40°C for up to 168 h) of the feral rubber coated sheets for rubber bands 98% of di- and 66% of tri-CNs vaporized. A loss rate of tetra-, penta-, and hexa-CN during initial 12 h of the weathering test ranged from ˜10 to ˜20%, while from 12 to 168 h remained negligible.

Airborne PM2.5/PM10-associated chlorinated polycyclic aromatic hydrocarbons and their parent compounds in a suburban area in Shanghai, China.

Chlorinated polycyclic aromatic hydrocarbons (ClPAHs) have been reported to be formed during incineration processes. Despite dioxin-like toxicities of ClPAHs, little is known on the occurrence of these chemicals in the environment. In this study, concentrations of 24-h airborne PM10 and PM2.5-associated ClPAHs and their corresponding parent PAHs were monitored from October 2011 to March 2012 in a suburban area in Shanghai, China. In addition, daytime and nighttime particle samples were collected for 7 days in April from the same sampling site. Twelve of twenty ClPAH congeners were found in PM10 and PM2.5 at concentrations ranging from 2.45 to 47.7 pg/m(3) with an average value of 12.3 pg/m(3) for PM10, and from 1.34 to 22.3 pg/m(3) with an average value of 9.06 pg/m(3) for PM2.5. Our results indicate that ClPAHs are ubiquitous in inhalable fine particles. The concentrations of ∑ClPAHs and specific congeners such as 9-ClPhe, 3-ClFlu, 1-ClPyr, 7-ClBaA, and 6-ClBaP in particles collected during nighttime were higher than those collected during daytime, which suggests not only diffusion of ClPAHs in air by atmospheric mixing but also photochemical degradation during daylight hours. Among the individual ClPAHs determined, 6-ClBaP, 1-ClPyr, and 9-ClPhe were the dominant compounds in PM10 and PM2.5. The percent composition of 6-ClBaP, 1-ClPyr, 7-ClBaA, and 3-ClFlu between PM10 and PM2.5 was similar. Significant positive correlations were found between concentrations of ClPAHs and their corresponding parent PAHs, particle mass, and total organic carbon (organic carbon plus elemental carbon), indicating that ClPAHs are sorbed onto carbonaceous matter of PM. Concentrations of parent PAHs predicted by multiple linear regression models with PM mass, total organic carbon, temperature, and relative humidity as variables reflected the measured concentrations with a strong coefficient of determination of 0.917 and 0.946 for PM10 and PM2.5, respectively. However, the models generated to predict ClPAH concentrations in PM did not yield satisfactory results, which suggested the differences in physical-chemical properties and formation processes between ClPAHs and their corresponding parent PAHs. 7-ClBaA and 6-ClBaP collectively accounted for the preponderance of the total dioxin-like TEQ concentrations of ClPAHs (TEQClPAH) in PM samples. Exposure to toxic compounds such as ClPAHs and PAHs present in PM2.5 can be related to adverse health outcomes in people.

Dioxin-like compounds in pine needles around Tokyo Bay, Japan in 1999.

Pine needle samples collected at ten spatially distant sites around Tokyo Bay in 1999 indicated a widespread lower troposphere pollution with ultra-trace dioxin-like compounds such as chlorodibenzo-p-dioxins (PCDDs), -furans (PCDFs), non-ortho- and mono-ortho-chlorobiphenyls (pPCBs), and -naphthalenes (PCNs). Elevated concentration of planar PCBs and the total PCNs were found at the sites which are located innermost to the Bay, suggesting the regional importance of the evaporative nature of the source of pollution by those compounds over this vast area. The concentrations and profiles for PCDDs and PCDFs remained largely uniform. An exception was the site near the town of Tateyama in the Chiba Prefecture, which is the southernmost but also relatively separate from the inner Bay. The site near Tateyama showed somehow background contamination with all compound groups and highly different profiles of PCNs. The principal component analysis (PCA) of the data matrix has revealed that around the Tokyo Bay, apart from the evaporative emission sources for PCNs and PCBs, combustion related processes also play an important role as sources of the ambient air contamination not only with PCDDs/Fs but also with chloronaphthalenes and planar chlorobiphenyls.

Transport of perfluoroalkyl substances (PFAS) from an arctic glacier to downstream locations: implications for sources.

Perfluoroalkyl substances (PFAS) have been globally detected in various environmental matrices, yet their fate and transport to the Arctic is still unclear, especially for the European Arctic. In this study, concentrations of 17 PFAS were quantified in two ice cores (n=26), surface snow (n=9) and surface water samples (n=14) collected along a spatial gradient in Svalbard, Norway. Concentrations of selected ions (Na(+), SO4(2-), etc.) were also determined for tracing the origins and sources of PFAS. Perfluorobutanoate (PFBA), perfluorooctanoate (PFOA) and perfluorononanoate (PFNA) were the dominant compounds found in ice core samples. Taking PFOA, PFNA and perfluorooctane-sulfonate (PFOS) as examples, higher concentrations were detected in the middle layers of the ice cores representing the period of 1997-2000. Lower concentrations of C8-C12 perfluorocarboxylates (PFCAs) were detected in comparison with concentrations measured previously in an ice core from the Canadian Arctic, indicating that contamination levels in the European Arctic are lower. Average PFAS concentrations were found to be lower in surface snow and melted glacier water samples, while increased concentrations were observed in river water downstream near the coastal area. Perfluorohexanesulfonate (PFHxS) was detected in the downstream locations, but not in the glacier, suggesting existence of local sources of this compound. Long-range atmospheric transport of PFAS was the major deposition pathway for the glaciers, while local sources (e.g., skiing activities) were identified in the downstream locations.

Clophen A60 Composition and Content of CBs, CNs, CDFs, and CDDs after 2D-HPLC, HRGC/LRMS, and HRGC/HRMS Separation and Quantification

Abstract Chlorobiphenyl (CB) and by-side chlorodibenzofuran (CDF), chlorodibenzo-p-dioxin (CDD), and chloronaphthalene (CN) homologue group and congener composition, and concentrations have been examined in technical CBs mixture Clophen A60. 101 peaks representing 116 CB congeners were quantified in Clophen A60, and most contributing were CBs nos. 138, 153, 134/144/149, and 180 with 15.4, 12.3, 8.2, and 6.5%, respectively. Di-, tri-, tetra-, penta-, hexa-, hepta-, and octa-CBs constituted, respectively, 0.03, 0.03, 0.32, 9.9, 52.7, and 4.9% of chlorobiphenyls content of the Clophen A60, while mono-, nona-, and decaCB were not quantified. Tetra- to octaCDDs were absent in Clophen A60 at concentration above the method limit of quantification of <0.01 μg/g, while the total CDFs and CNs were found at 12 and 42 μg/g, respectively. Tetra-, penta-, hexa-, and hepta-CDF with 27, 46, 19, and 7% contribution, respectively, dominated in homologue group profile of CDFs, while octa-CDF was absent in Clophen A60. In compositional profile of CDF congeners the most abundant were 1,2,4,7,8-PeCDF, 2,3,4,7,8-PeCDF, and 1,2,3,4,7,8-HxCDF and each had >5% contribution. Amongst the CN homologue groups the profile in descending order followed by hepta-, hexa-, octa-, and penta-CNs with 56, 26, 16, and 2%, respectively. In compositional profile of CNs the most abundant were the congeners such as 1,2,3,4,5,6,7-HpCN (no. 73), 1,2,3,4,6,7-/1,2,3,5,6,7-HxCN (nos. 66/67), and 1,2,3,4,5,6,7,8-OcCN (no. 75) with 55, 21, and 16%, respectively. In terms of dioxin-like toxicity of Clophen A60 the contribution from planar non-ortho and mono-ortho CBs, CDFs, and CNs was 5280, 594.5, and 33.1 ng TCDD TEQ/g, respectively, and the total TEQ of planar analogues was 5908 ng/g.

Mechanisms of olfactory toxicity of the herbicide 2,6-dichlorobenzonitrile: Essential roles of CYP2A5 and target-tissue metabolic activation

The herbicide 2,6-dichlorobenzonitril (DCBN) is a potent and tissue-specific toxicant to the olfactory mucosa (OM). The toxicity of DCBN is mediated by cytochrome P450 (P450)-catalyzed bioactivation; however, it is not known whether target-tissue metabolic activation is essential for toxicity. CYP2A5, expressed abundantly in both liver and OM, was previously found to be one of the P450 enzymes active in DCBN bioactivation in vitro. The aims of this study were to determine the role of CYP2A5 in DCBN toxicity in vivo, by comparing the extents of DCBN toxicity between Cyp2a5-null and wild-type (WT) mice, and to determine whether hepatic microsomal P450 enzymes (including CYP2A5) are essential for the DCBN toxicity, by comparing the extents of DCBN toxicity between liver-Cpr-null (LCN) mice, which have little P450 activity in hepatocytes, and WT mice. We show that the loss of CYP2A5 expression did not alter systemic clearance of DCBN (at 25 mg/kg); but it did inhibit DCBN-induced non-protein thiol depletion and cytotoxicity in the OM. Thus, CYP2A5 plays an essential role in mediating DCBN toxicity in the OM. In contrast to the results seen in the Cyp2a5-null mice, the rates of systemic DCBN clearance were substantially reduced, while the extents of DCBN-induced nasal toxicity were increased, rather than decreased, in the LCN mice, compared to WT mice. Therefore, hepatic P450 enzymes, although essential for DCBN clearance, are not necessary for DCBN-induced OM toxicity. Our findings form the basis for a mechanism-based approach to assessing the potential risks of DCBN nasal toxicity in humans.