Hajime Muto

PCDDs and PCDFs carried to the human body from the diet

Abstract This is a report of dynamic aspects of the selective accumulation of tetrato octa-chlorinated dibenzo-p-dioxins (PCDDs) and -furans (PCDFs) in food stuffs and human tissues in northern Japan. Large amounts of PCDDs and PCDFs were in fish/shellfish and meats with fats, while very little PCDDs and PCDFs were in vegetables. The cumulative amounts of PCDDs and PCDFs found in the Japanese human tissues was highest in adipose tissues, followed by lung, liver and kidney. On a fat basis, however, the levels of PCDDs and PCDFs were roughly similar for all tissues. The daily intake of PCDDs and PCDFs was approximated to 1,010 and 828 ng/day/capita, respectively. Regarding the route of PCDDs and PCDFs being taken up by the human body, importance seems to be presently living attributed to the uptake via food.

PCDD/DF formations by the heterogeneous thermal reactions of phenols and their TiO2 photocatalytic degradation by batch-recycle system

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/DFs) formation by the thermal reactions of phenols with CuCl2 under oxygen flux were carried out in relation to their formation mechanisms. To evaluate the effect of photocatalytic degradation of titanium dioxide (TiO2) thin film prepared by the sol-gel method, the photocatalysis of PCDD/DFs in acetonitrile/water solution by batch-recycle system was conducted. For the thermal reaction system of powder mixtures of 2,4,5-trichlorophenol (2,4,5-TCP) and CuCl2, the formation rates were 8.1 microg/g-2,4,5-TCP/min for total PCDD/DFs and 6.9 microg/g-2,4,5-TCP/min for PCDDs, and total PCDD/DF rate was higher by approximately 40 fold compared to phenol vapor/oxygen/CuCl2 powder system. For the system of 2,4,5-TCP, PCDDs were mainly formed via ortho-phenoxyphenols (POP) intermediate by the condensation of 2,4,5-trichlorophenate. For PCDD/DF photocatalytic degradations, most PCDD congeners photodecomposed rapidly and the rates presented more than 70% (as dechlorination rates of 76% for PCDDs) at 24 h after irradiation, using PCDD/DFs formed with 2,4,5-TCP. The rate constants were in the order of 4.8-6.1 x 10(-3) min(-1), assuming the pseudo-first-order reactions for their low levels.

Simultaneous multielemental analysis of daily food samples by inductively coupled plasma mass spectrometry

Several toxic elements in total composite food samples of hospital diets were determined simultaneously by inductively coupled plasma mass spectrometry (ICP-MS). Trace element concentrations of Be, Cr, As, Cd, Sn, Sb, Ce, Hg and Pb changed widely ranging from a few ng.g-1 to less than 3 micrograms.g-1 in all 24 samples collected through a year. Be, Sn, and Hg were not detected in rice sample alone, and other trace elements, with the exception of Cr and As, were less than approximately 50% levels, as compared with mixed diet samples. The daily intakes of these toxic elements were in the ranges of a few to several hundreds of micrograms.

Polychlorinated dibenzo-p-dioxins and dibenzofurans in plywood combustion gas

Polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/DF) levels in plywood combustion gas were investigated for the effects of ammonium chloride (NH4Cl) and paint. For combustion systems in which neither NH4Cl nor paint were present in the plywood samples, total amounts of PCDD/DFs in the combustion gas were in the order of 35-529 ng/Nm3, and were higher in the systems with softwood trees than broadleaf ones, depending on the Cl concentrations. For the systems with added NH4Cl and no paint, and those without NH4Cl but were painted, higher PCDD/ DF rates were observed at combustion temperatures of 270 degrees C and 500 degrees C, respectively. However, for the systems with both NH4Cl and paint, their amounts in the range of 0.6-13 ng/Nm3 were the lowest in all systems. The PCDD/DF abundance profiles were similar to their patterns in pentachlorophenol (PCP). Furthermore, it was found that the 2,3,7,8-chlorine substituted penta- and hexa-CDDs contributed more than other 2,3,7,8-chlorine substitutes to toxicity equivalency (TEQ).

Concentrations of various elements and inorganic ions in rice straw and ash

Various elements and inorganic ions in rice straw and ash samples were analyzed by using inductively coupled plasma atomic emission spectrometry (ICP‐AES) and ion chromatography (IC). Five major elements: Mg, Mn, Al, Ca, and Fe and eight minor and trace elements: Cr, Cu, Ti, Zn, La, Sr, Ba, and Hg were detected in these samples, at more than ppm‐level. In ash samples the trace elements such as Y, As, V, Se, and Sc were also identified. The concentrations of SO4, PO4, Cl, Na, and K ions in these samples were higher than those of other ions measured. These elements and inorganic ion concentrations were approximately one order of magnitude higher in the ash than in the straw samples. Gas chromatography/mass spectrometry (GC/MS) and library search showed the presence of fatty‐, carboxylic‐ and nicotinic acids, and their derivatives in small quantities in the straw samples.

Rapid changes in concentrations of essential elements in organs of rats exposed to methylmercury chloride and mercuric chloride as shown by simultaneous multielemental analysis.

An in vivo study of rats given a dominant lethal dose of methylmercury chloride (MMC) or mercuric chloride (HgCl2) was conducted to elucidate the rapid biotransformation of essential elements. The elements were measured by inductively coupled plasma atomic emission spectrometry. For the rat brain Zn concentrations were higher in the MMC group than in the HgCl2 and control groups. The highest Cu concentration was found in HgCl2 dosed rat liver. For the rat kidney the highest Zn concentration was seen in the MMC group. From principal component analysis on the time dependent behaviour of each element in rat organs, characteristics specific to Cu in the liver and kidney and Mn in the brain were found after exposure to HgCl2 and Ca and Zn in the brain after exposure to MMC.

Concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans from chemical manufacturers and waste disposal facilities

Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were measured in various source and environmental samples obtained from eight chemical manufacturers producing agricultural chemicals, synthetic dye, or resin and eight chemical waste disposal facilities. The concentrations of PCDDs and PCDFs ranged from 3.0 to 3504 ng/g for PCDDs and from 1.2 to 1668 ng/g for PCDFs in fly ash. Their concentrations in emission were in the ranges of 21.8 to 3205 ng/m3 for PCDDs and not detected to 4344 ng/m3 for PCDFs. PCDD and PCDF concentrations were higher in fly and bottom ashes and in emissions from two manufacturers that incinerate waste plastics than in those from other manufacturers. For emission and liquid samples from the manufacturers. For emission and liquid samples from the manufacturers of agricultural chemicals, significantly high concentrations of tetra-CDDs were detected. Furthermore, the high concentrations of PCDFs, especially hepta- and octa-CDF congeners, existed in emissions from waste incinerators that manufacture rubber. Among manufacturers and disposal facilities, the total emission equivalent (2.94 ng/m3) of PCDDs and PCDFs was highest for a certain manufacturer of agricultural chemicals, showing that more 2,3,7,8-chlorine-substituted PCDDs and PCDFs were present in their emissions.

Induction of phospholipid peroxidation and its characteristics by methylmercury chloride and mercuric chloride in rat kidney

Abstract The structural interaction between mercurials and phospholipids has been suggested, and in this paper, we report the formation of individual phospholipid peroxide by mercurials using multi-channel ultra violet (UV)-high-performance liquid chrpmatography(HPLC) system combined with the potentiometric determination. Rats were dosed with HgCl 2 (0.5 mg/kg/day) for 3 days or methylmercury chloride(MMC) (10mg/kg/day) for 5 days. Produced peroxides in HgCl 2 dosed rat kidney were mainly phosphatidylserine(PS), phosphatidylethanolamine(PE) and phosphatidylcholine(PC) peroxides. Formation of peroxides was decreased by the administration of vitamin E(vit. E). These results led us to suggest that one aspect of the induction of lipid peroxidation by mercurials might result from the interaction of mercurials with the primary amine group of phospholipids, as well as the other suggested mechanisms such as the effects of the radicals on the unsaturated fatty acids and the influences on some antioxidative enzymes.

Filtering effects to bacteria and improvement of water quality by granite porphyry materials

Abstract The authors have investigated the filtering effects to bacteria and E. coli and the elution/adsorption for minerals, residual chlorine, COD, and organochlorine compounds by using granite prophyry, Bakuhanseki. The filtering effects of Bakuhanseki to bacteria were appeared, particularly the reduction rates of E. coli were 24.5 ± 8.32 and 84.4 ± 1.50% for Taihei river water samples and more than 50% for bath water samples, and the effects were accelerated by silver-coated Bakuhanseki materials. Residual chlorine and COD components in tap water reduced rapidly by one-pass flow through Bakuhanseki layer, and in the cyclic treatment system with the layer, the increases in concentrations of essential elements of Na, K, Fe and Ca were particularly shown, as well as the decreased concentrations of trihalomethanes and related compounds.

The tissue distribution of 2,3,7,8-chlorine substituted dibenzo-p-dioxins in humans who died of cancer

The tissue distribution of 2,3,7,8-chlorine substituted dibenzo-p-dioxins was conducted in 11 patients who died of cancer. The concentration of octachlorodibenzo-p-dioxin (octa-CDD) was the highest in each organ and tissue and hepta-CDD was also found at relatively high levels, second only to OCDD. The levels of 1,2,3, 7,8-penta-CDD and 1,2,3,6,7,8-hexa-CDD in the spleen were the highest, respectively. 2,3,7,8-Tetra-CDD was also detected and its concentration was the highest in the gonad (0.8-3.2 pg/g-range). From the 2,3,7,8-TCDD toxic equivalent calculations, the highest equivalent value was obtained from a 54-year-old female who died of cancerous goiter. This individual had the highest concentrations of 2,3,7,8-substituted penta- and hexa-CDDs among the 11 patients.