Tadaaki Wakimoto

Isomer-specific determination of polychlorinated dibenzofurans in Japanese and American polychlorinated biphenyls

Abstract Extremely toxic Polychlorinated dibenzofurans (PCDFs) were identified in several Japanese and American commercial PCB preparations. These isomerspecific analyses revealed several toxic PCDFs including 2,3,7,8-tetra-, 1,2,4,7,8-penta-, 1,2,3,7,8-penta-, 2,3,4,7,8-penta- and 1,2,3,6,7,8 hexa-chlorodibenzofurans in commercial PCB preparations. The concentrations (μg/g) of PCDFs in unused Kanechlor 300, 400, 500, 600 were 7.5, 26, 7.2, 5.4 and in Aroclors 1242, 1248, 1254, 1260 were 0.60, 3.7, 4.2, 7.5 respectively. An attempt for the detection of polychlorinated dibenzo-p-dioxins (PCDDs) at

Polychlorinated dibenzo-p-dioxins and dibenzofurans in human adipose tissues of Japan

Abstract Thirteen samples of human adipose tissue from cancer patients in Japan were analyzed for tetra- to octa- chlorinated dibenzo- p -dioxins (PCDDs) and dibenzofurans (PCDFs). These compounds were identified in all the samples analyzed. All isomers identified have a pattern of chlorine substitution in 2, 3, 7 and 8 positions with the only exception of 1,2,3,4,6,7,9-hepta-CDD. In the case of PCDFs, the relatively higher persistency was found in the isomers with chlorine atoms at 4- (or 6-) position as compared with 1- (or 9-) position. Total PCDD concentrations were in the range of 160 to 1400 pg/g on wet weight basis, in which increasing levels were found from tetra- to octa-CDD. Total PCDF concentrations were in the range of 7 to 120 pg/g and the levels of individual congeners are rather uniform.

Composition of chloronaphthalene congeners in technical chloronaphthalene formulations of the Halowax series

Abstract Normalised pattern (DB‐5 capillary column) of polychlorinated naphthalenes (PCNs; CNs) for all seven technical Halowax formulations and mass percent contribution (CN %) for an equivalent mixture of Halowax 1031, 1000, 1001, 1099, 1013, 1014 and 1051 (Equi‐Halowax) is presented. 2,3‐DiCN (PCN no. 10), 1,6,7‐and 2,3,6‐TrCNs (PCNs nos 25 and 26) and probably also 1,3,5‐TrCN (PCN no. 19), 1,3,6,7‐, 1,2,3,6‐and 1,2,3,8‐TeCN (PCNs nos. 44, 29 and 31), and 1,2,3,6,7,8‐HxCN (PCN no. 70) were absent in commercial PCNs formulations. The congeners such as 1,2,3‐TrCN (PCN no. 13), 1,3,8‐TrCN (PCN no. 22) and 1,2,3,6,7‐PeCN (PCN no. 54) were present in the mixtures at very low concentrations. The congeners most abundant in Halowax mixtures are usually chlorinated at α‐positions (1, 4, 5, 8‐positions) of the naphthalene nuclei. Because of some unresolved peaks observed on the chromatograms due to insufficient separation power of DB‐5, and also of many other liquid phases used in capillary gas Chromatographie separation of PCNs even when mass spectrometric detection was used, a perfect isomer and congener composition of PCN mixtures still has to be elucidated.

Organochlorine pesticides, polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins and dibenzofurans in human adipose tissue from western Kyungnam, Korea

Hexachlorocyclohexanes (HCHs), dichlorodiphenyl trichloroethane and its metabolites (DDTs), hexachlorobenzene (HCB), polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/DFs) were determined in human adipose tissue samples collected from western Kyungnam, Korea. The residue levels of organochlorine compounds were in the order of DDTs followed by PCBs > HCHs > HCB > PCDDs/DFs. The mean concentrations of 2,3,7,8-TeCDD in male and female tissues were 2.8 and 1.7 pg.g-1 on lipid weight basis, respectively. No significant difference was found in the residue levels of PCDDs/DFs between sexes. In contrast, PCBs and DDTs showed a significant difference between sexes. Unlike the age trend observed for HCHs, PCBs and DDTs, PCDDs/DFs revealed a constant or rather decreasing pattern with increasing age. This is the first report on PCDDs/DFs contamination in human adipose tissue from Korea. Organochlorine concentrations in human adipose tissues from western Kyungnam were generally much lower than those of other countries.

Dibenzofurans a greater global pollutant than dioxins ?: Evidence from analyses of open ocean killer whale

Abstract Three specimens of killer whales (Orcinus orca), an open ocean carnivore, were analysed for extremely toxic polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) to understand their long-range distribution patterns. Several PCDF congeners, including the highly toxic 2,3,7,8-tetra- and 2,3,4,7,8-penta-CDFs were identified in the blubber of those specimens. The PCDF isomeric pattern in killer whale is more complex than the reported patterns in humans and birds, indicating the weaker metabolic potency of killer whales for these toxic compounds. High levels of PCBs (about 400 mg kg−1) have also been detected in those specimens. The 2,3,7,8-substituted PCDF congeners identified in commercial PCBs were also found in killer whale, indicating PCBs as the possible source. Isomer-specific and trace level determinations of PCDD in killer whale, revealed no detectable quantities. The detection of comparatively high levels ( > 300 ng kg−1) of PCDFs and undetection of PCDDs in open ocean killer whales suggest that PCDFs are more ubiquitous than PCDDs.

A simple method for determining non-ortho substituted PCBs in Kanechlors, Aroclors and environmental samples

Abstract 3,3′,4,4′-tetra, 3,3′,4,4′,5-penta and 3,3′,4,4′,5,5′-hexachlorobiphenyl are known to be the most toxic PCBs. We developed an isomer specific analytical method for these congeners by combining alkali digestion, carbon chromatography, HR-GC-ECD and GC-MS. Our method revealed the presence of these toxic congeners in wildlife and humans at ppb and higher ppt levels. They were also detected in Aroclors and Kanechlors ranging from several hundred to thousand ppm of tetra, few ppm to several ten ppm of penta and several hundred ppb or less of hexachlorobiphenyl.

Dioxin-like potencies and extractable organohalogens (EOX) in medical, municipal and domestic waste incinerator ashes in Japan

Ash samples collected from medical, municipal and small-scale domestic incinerators in Japan were tested for dioxin-like activity using bioassay technique (ethoxyresorufin-O-deethylase: EROD assay) and for extractable organohalogens (EOX) using instrumental neutron activation analysis in order to estimate potential toxicity and responsible chemicals in those samples. Crude extracts and fractions cleaned-up for dioxin analysis from the samples were used for the analysis. The ranges of dioxins in the ashes were between 2.23 and 12.29 ng TEQ/g (dry weight). Relative potency ranges estimated by EROD assay in the medical incinerator ashes were 3.8-17.6 times higher than the results of conventional chemical analysis. EOX analysis suggested that ash samples contained plenty of organochlorine compounds apart from chlorinated dioxins. In addition, medical waste incinerator ashes were considered to have relatively higher amount of organoiodine compounds. In the cleaned-up fractions, bioassay potency ranges were lower than those in the crude extracts. However, some samples still exhibited higher potency than expected from chemical analysis. Though some polycyclic aromatic hydrocarbons were found in the fractions, the amounts were relatively low (0.39-10.56 ng/g). The results imply that some bioactive organohalogens that cannot be detected in the conventional chemical analysis might have potential for dioxin-like toxicity, and contribute to higher bioassay activities. The combination of the chemical analysis with the bioassay and EOX provides rough figure of dioxin-like toxicity and suggests types of organohalogen compounds that should be identified as a part of dioxin analysis for control emission from an incineration plant.

PCDDs in the sediments accumulated about 8120 years ago from Japanese coastal areas

Abstract PCDDs, PCDFs and PCBs were found in the surface sediments after about 1950 of sediment cores in Japanese coastal areas. However, only PCDDs could be detected in the deep sediments, but any other related compound could not found. The levels of PCDD found in deep sediments exceeded blank levels by far. These PCDDs were not due to contamination. We must assume that some PCDDs existed before industries developed.

Persistent organochlorines in Japanese coastal waters: an introspective summary from a Far East developed nation

Abstract Japan has emerged as one of the leading industrialized nations and economic powers in the world. The rapid modernization and industrial development required to achieve this have in certain cases created environmental deterioration and instances of adverse impacts upon public health. This review summarizes the historical, present and likely future impacts of persistent organochlorine contaminants on the health of the coastal waters of Japan. It is noted that contaminants such as DDT, HCH, and PCBs are generally exhibiting decreased abundances in Japanese coastal waters with time. However, new environmental challenges are emerging in Japan, including the contamination of coastal ecosystems by chlordane, particular organophosphate compounds, dioxins, dibenzofurans, and coplanar PCBs. Extensive studies are continuing on these contaminants, some of which are of considerable toxicological concern in aquatic environments.

Daily intake of PCDDs and PCDFs by Japanese through food

Abstract Based on the standard energy and food compositions of Japanese, food items for a week (21 meals) were purchased from Matsuyama markets and analyzed for tetra- through oct-chlorinated dibenzo- p -dioxins and dibenzofurans. PCDDs/PCDFs were detected at low ppt levels from all categories of analyses. The daily intake of PCDDs/PCDFs was estimated to be about 6000 pg. 2,3,7,8-TCDD equivalent (USEPA) of daily intake from food was calculated to be 63 pg/man/day or 1.3 pg/kg body weight/day for a person weighing 50 kg. This is fairly close to the tentative ADIs (1–5 pg/kg/day) established in several countries.