Recently, diesel engine powered cars has been increasing steadily in Japan, because diesel engine is powerful and the fuel is less expensive. Diesel exhausts emit some 2 to 20 times more nitrogen dioxide and some 30 to 100 times more particles than do gasoline engine cars. The exhausts are main cause of air pollutants in urban area, and people are anxious about that the exhausts may cause lung diseases such as asthma and lung cancers. There are clinical and epidemiological studies on relationship between asthma and diesel exhausts. However, it is not yet confirmed with experimental study. Here, I will introduce recent experimental data that essential features of asthma such as chronic inflammation with eosinophil-infiltration, mucus hypersecretion and airway hyperresponsiveness has been caused by diesel exhaust particles, and that the active oxygens generated from diesel exhaust particles may play an important role to cause asthmatic symptoms. The other hand, it is well established that diesel exhausts can cause lung tumors experimentally using F-344 rats. In this case, it is considered that carcinogens contained in benzene extract-fraction of the diesel exhaust particles are important. However, it has been found that diesel exhaust particles washed out sufficiently with organic solvent can also cause lung tumors. Therefore, the significance of carcinogens in diesel exhaust particles on the actual carcinogenesis is also introduced.

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Fluorene-2-diazonium salt (FD) is produced by the reaction of 2-amino fluorene with nitrite and is highly mutagenic to Salmonella typhimurium TA 98 and TA 100 strains without requiring metabolic activation. The reactivity of FD towards DNA and its components was investigated. FD was unstable around neutral pH being converted into a number of products including 2-hydroxyfluorene and fluorene. Electron spin resonance studies using spin-trapping agents, 5, 5-dimethyl-1-pyrroline N-oxide (DMPO) and N-tertbutyl-α-phenylnitrone (PBN), revealed that the carbon-centered radical, i.e., the fluorene radical, was generated from FD. FD effectively damaged Guo, dGuo, Ado, dAdo, dThd and dCyd, as demonstrated by high performance liquid chromatography, and cleaved supercoiled and double-stranded linear DNA as shown by agarose gel electrophoresis. The single strand breaking of supercoiled DNA by FD was inhibited by the hydrogen donors, ethanol, 2-mercaptoethanol and cysteine, as well as a spin-trapping agent DMPO, indicating the participation of the carbon-centered radical generated from FD in the DNA strand breaking.

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About 400 aerobic heterotrophic bacteria, including three pollution and one unpollution index bacterial types, isolated from a total of 22 stream waters were examined to determine their utilization of low molecular weight organic compounds and their hydrolysis of high molecular weight organic compounds. The results showed that the ability to utilize low molecular weight organic compounds of two yellow pigmented bacterial types of the pollution index bacteria was much lower than that of other bacterial types. Those two bacteria which could not completely utilize the low molecular weight organic compounds, Flavobacterium YA1 and Flavobacterium YI, were then investigated. The quality of stream water was found to be reflected only by these two types, because the ratio of these isolates positively correlated significantly with many water quality variables. In investigating the validity of these bacteria as pollution indicators, the bacterial number of Flavobacterium YA1 in polluted water with domestic waste was much higher than that in clean water such as tap water, whereas Flavobacterium YI was detected only in clean water. These results suggest that Flavobacterium YA1 may be a good candidate as a pollution indicator of domestic waste in stream water.

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It is suspected that pentachlorophenol (PCP), used as an organochlorine herbicide, has toxicity related with the lipid peroxidation. The lipid peroxidation by the in vitro metabolism of PCP in a microsomal system was inhibited by riboflavin tetrabutyrate (B₂-But), a fat-soluble riboflavin, but not inhibited by water-soluble flavins. The lipid peroxidation in the liver of mice exposed to 35 μmol/kg of PCP was suppressed by the simultaneous administration of B₂-But, but scarcely suppressed by other flavins. Moreover, the changes of mitochondrial ADP/O ratio and flavin contents in the liver of mice were also suppressed by B₂-But. It was considered that the suppressive effect of B₂-But on the liver injury by PCP due to the inhibition of the lipid peroxidation and the flavin supply by B₂-But in the liver.

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The possibility that the hepatic toxicity of trichloroethylene (TCE) relates to the increase of lipid peroxide in the liver is investigated. When 0.12 mmol/kg, 0.6 mmol/kg or 1.2 mmol/kg of trichloroacetic acid (TCA) or TCE was administered to a mouse at a single dose, the content of thiobarbituric acid reactive substances in the liver increased in a dependent manner, while the contents of flavin and GSH, and the activity of mitochondrial ATP synthesis in the liver decreased. There was a significant correlation between these parameters. These results suggest that the lipid peroxidation and the decrease of mitochondrial ATP synthesis in the liver of mice caused by TCA or TCE relate to the liver injury.

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Coloring is added to many foods and beverages to compensate for the loss of color during processing and to enhance their visual appeal. We have been studying the effect of food additives around the ADI level on cellular functions using washed rabbit platelets. The present study has been carried out to investigate the effect of artificial red colors on rabbit platelet functions both in vitro and ex vivo. Among seven red colors used, Nos. 3, 104 and 106, which are xanthene dyes, had an inhibitory effect on A-23187 induced TXB₂ synthesis at the concentration of 0.01-0.05% when added simultaneously in vitro. On the other hand, all seven colors affected thrombin induced TXB₂ synthesis at the concentration of around 0.01%. Namely, Nos. 2, 3, 40, 102, 104 and 105 inhibited and No. 106 stimulated thrombin induced TXB₂ synthesis. In the pretreatment, only No. 106 had a reversible inhibitory effect on A-23187 induced TXB₂ synthesis, but thrombin induced ones were inhibited by Nos. 2, 3, 40, 102, 104 and 105. These inhibitions were irreversible in the cases of Nos. 3 and 104. Thrombin induced TXB₂ synthesis in the platelet from rabbit fed ADI levels of Nos. 3, 102, 104, 105 and 106, with the diet for 5 d was stimulated. These results indicate that the amount of these compounds added to foods should be reduced to the minimum necessary to lower the risk of their potential hazard to humans.

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We developed a new time series analysis [TSA] for long-term variation with seasonal variation in concentrations of environmental components. The regression curve with two terms is used in this TSA. One term means long-term tendency of an increase or a decrease in concentration of the component. Another gives numerical information about seasonal variation, i.e. time when the highest concentration is observed in a year and regularity on seasonal cycle. The proposed TSA was successfully applied for characterizing the long-term variation in the amount of soluble and insoluble compounds in deposit samples collected for 12 years in Kanazawa. Variations in inorganic components in deposit samples were divided into three classes and five groups. This classification was in good agreement with that obtained by the factor analysis [FA]. Our TSA seemd to be helpful in characterizing the factors in FA.

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Tributyl phosphate (TBP) in flame retardant textiles was analyzed by capillary gas chromatography using a flame photometric detector (FPD). A successfully cleaned up preparation using the difference in liquid-liqiud partition behaviour and a florisil cartrige column has been developed for the determination. The detection limit by this method was 10 pg. For the determination of TBP in textiles, TBP was extracted from samples with methanol under reflux at 70°C. For the removal of polar materials, distilled water was added to the extract, and TBP was reextracted into dichrolomethane from the methanolic phase. After evaporating the extract, the residue was dissolved in n-hexane, and applied to the florisil cartrige column. After washing nonpolar materials with n-hexane, TBP was eluted with n-hexane containing 10% methanol. After evaporating the elute, the residue was dissolved in n-hexane, and applied to the GC. The recoveries of TBP added to textiles at the amounts of 2, 20, 200, 2000 μg were 93-96% on the average. TBP was detected in 3 out of 8 brands in textiles finished as flame retardant by this proporsal method.

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Sorbic acid isolated from foods through steam distillation was extracted with ether, followed by the addition of dioxane and concentration under reduced pressure until the ether vapor was removed. Sorbic acid in the resulting solution was treated with 4-phenyl-1, 2, 4-triazoline-3, 5-dione in dioxane at 70°C, followed by methylation of the resultant Diels-Alder adduct with an ethereal diazomethane to give the corresponding methyl ester as a volatile compound for the determination using the GC method. Compared with the detection by FID, that by FTD was found to be about 100 times, since the volatile compound has three nitrogen atoms which are characteristic for FTD in the molecule. Accordingly, the GC method using 4-phenyl-1, 2, 4-triazoline-3, 5-dione is applicable to the microanalysis of sorbic acid

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A simple and sensitive method was developed for the determination of total iodine in iodine-enriched eggs (IEs). The egg yolk and white of IE were homogenized with ethanol. The homogenate was decomposed by oxygen flask combustion with an alkaline absorbing solution. After the combustion, iodide (I^-) obtained in the absorbing solution was concentrated by solid-phase extraction with an anion-exchange column. The concentrated I^- was determined by reversed-phase HPLC with a UV detector. The reproducibility obtained for the determination was good. The recoveries of iodine added to the egg yolk and white were about 90%. The method was applied to the determination of total iodine in commercial IEs.

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