Mutagens which have been detected in our living environment during the past 10 years are classified by their existence in air, water, soil, food or in animal/human body, and are reviewed by taking current environmental problems. into consideration. New detecting systems for DNA damages, which could be applied to monitor the environmental mutagens for the risk assessment of humans, are surveyed. Various inhibitors in mutagenesis and carcinogenesis including desmutagens and bioantimutagens are summarized on the basis of their modes of action. Importance of the development of new detecting systems for antimutagens/anticarcinogens are discussed on their possible application in the field of chemoprevention of cancer.

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This paper deals with the investigation of simple and rapid method to determine the toxicity value (IC₅₀) of chemicals to activated sludge by using oxygen electrode. In this method, activated sludge was added to various concentrations of test chemicals and 50% inhibition of the oxygen uptake rate (OUR) was measured within 10 min. The IC₅₀ values calculated to be 1.5 mg/l, 1.5 mg/l, 4.0 mg/1, 7.2 mg/l, 14 mg/1, 14mg/l, 20 mg/l, 75 mg/l, 108 mg/l and 2500 mg/l for mercury (II) chloride, copper (II) chloride, mercury (II) acetate, copper (II) acetate, 2, 3, 5-trichlorophenol, pentachlorophenol, p-nitrophenol, 3, 4-dimethylphenol, cyclohexylamine and aniline, respectively, agreed almost well with those reported in the literatures. In addition, the OUR of activated sludge inhibited specifically by mercury (II) chloride was easily recovered by the addition of thiol compounds such as 2-mercaptoethanol, thiosulfate and reductive glutathione, respectively. Reactivation by thiol compounds suggested that mercury (II) form reversible mercaptides with sulfhydryl groups of enzymes concerned in OUR. From these results, the OUR method would be applicable to a rapid determination for biochemical field or biodegradation test in the Law Concerning the Examination and Regulation of Manufacture, etc. Chemical Substances.

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The Gerber method was modified to determine the lipid level, and the relationship between metallothionein and lipid concentrations was studied in the mice liver. After the injection of several compounds including cadmium, the lipid level did not increase but the concentration of metallothionein increased. On the other hand, the starvation or the injection of carbon tetrachloride, colchicine, safrol, or tannic acid increased both the hepatic concentrations of metallothionein and lipid. Fatty liver caused by colchicine, which induced metallothionein, was prevented by cycloheximide. These results indicate that the concentration of metallothionein in the liver increased with increasing the lipid level in the tissue.

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Twelve sorts of foods were tested to investigate the changes in the contents of ascorbic acid, vitamin B₁ and vitamin B₂ by soaking in 0.5 ppm chlorine dioxide solution. These vitamins in food were extracted with ultrasonic generator for 30 min, and the percentages of the loss of ascorbic acid, vitamin B₁ and vitamin B₂ were determined by the dichlorphenolindophenol method, thiochrome fluorescence method and lumifulavin method, respectively. It was found that there were the loss of 0-5% in the contents of vitamins after soaking for 15 min and 15-30% after 60 min. However, the percentage of the loss induced by the chlorine dioxide solution was less than that induced by 0.5 ppm chlorite, 0.5 ppm hypochlorite and potable water. The existence of Fe³⁺, Cu²⁺ in the solution had an obvious effect which accelerates the decomposition of ascorbic acid.

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Several preconcentration methods for the detection of organic mutagens in water, including blue rayon and XAD-2 resin column methods, were compared. The mutagenicity test of the extracts from blue rayons hung at the six points of the Yodo river revealed similar frame-shift type mutagenicity to our previous report with the XAD-2 resin column method. For the quantitative concentration of polycyclic aromatic hydrocarbons in water, it was shown that the blue rayon column method was more efficient than the blue rayon hanging method or XAD-2 resin column method. Extracts from the Yodo river water and sewage treatment plant effluent obtained by the XAD-2 resin column and blue rayon hanging methods may contain nitroarenes and aminoarenes.

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Fifty percent of ethanolic extracts from the immature fruits of Citrus reticulata BLANCO, C. tamurana hort. ex TANAKA, C. natsudaidai HAYATA and C. unshiu MARKOVICH showed a significant inhibitory effect on the activation of inactive hyaluronidase induced by compound 48/80. This effect decreased with the maturation of the fruit in all cases. Among the citrus fruits tested, the extract from the immature C. reticulata BLANCO showed the strongest inhibitory effect. The data of gel permeation chromatography and gas chromatography-mass spectrometry showed the hyaluronidase inhibitor in the fruit to be a pectin with a molecular weight of 1.1×10⁵. The content of D-galacturonic acid in the pectin was determined to be 58% using the carbazole method. The pectin showed almost the same inhibitory effect (IC₅₀ : 91 μg/ml) as a commercial pectin from oranges or a current anti-allergic agent, disodium cromoglycate. Hyaluronidase has been suggested to be one of the target enzymes controlling the degranulation of mast cells, and the inhibitory effect on the activation of inactive hyaluronidase has been reported by Kakegawa et al. (Chem. Pharm. Bull. 33 [1985]) to be an index of anti-allergic activity. Therefore, it is expected that the pectin in C. reticulata BLANCO might possess anti-allergic potential.

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For the evaluation of 2-alkenal as a precursor of thiobarbituric acid reactive substance (TBA-RS), 2-alkenal (C₃-C₉ and 2, 4-hexadienal) was incubated with tert-butyl hydroperoxide (t-BuOOH) at 40°C for 2 hr, Fenton reagent (H₂O₂/Fe²⁺) or hypoxanthine-xanthine oxidase (Hx-XOD) in citrate buffer at 37°C for 1 hr. A reaction mixture was made to react with thiobarbituric acid (TBA) in 70% acetic acid at 100°C for 30 min. The amount of red pigment formed from the 2-alkenal greatly increased by addition of t-BuOOH. These results indicate that the red pigment was formed from 2-alkenal by the addition of t-BuOOH during the incubation, but that was formed in the TBA reaction process. Then, the usage of TBA reagent containing Sn²⁺ (5 μmol), which prevents t-BuOOH oxidation in the TBA reaction, 14.6 and 12.5 mol% of TBA-RS were formed from 2-hexenal and 2, 4-hexadienal by heating with t-BuOOH at 100°C for 60 min, respectively. In Fenton reagent (H₂O₂/Fe²⁺), the amount of TBA-RS from 2, 4-hexadienal decreased to 28% during the reaction at 100°C for 60 min. In Hx-XOD, TBA-RS from 2-alkenal (C₃, C₄ and C₆) and 2, 4-hexadienal increased with superoxide oxidation. From the above results, it is suggested that 2-alkenal was decomposed with t-BuOOH oxidation and Hx-XOD system, and thiobarbituric acid reactive substances were formed.

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A case of contact dermatitis from a T-shirt was reported. The patient reacted to the polyurethane elastomer (PUE) tape used in the T-shirt, Tinuvin P which is a benzotriazole-type UV absorber, and one of 5 brands of commercially available PUE fibers. The analytical procedures for the determination of benzotriazole-type UV absorbers (Tinuvin P, 234, 326, 327, 328 and 329) were as follows : 1) extraction by shaking with a mixture of acetone : chloroform (1 : 1) at room temperature ; 2) fractionation by column chromatography on silica gel by using hexane, dichloromethane, ethyl acetate and methanol as eluting solvents ; 3) qualitative and quantitative analyses by gas chromatography (GC), GC-mass spectrometry (GC-MS) and high performance liquid chromatography (HPLC). Chemical analysis revealed that Tinuvin P was contained in the causative PUE tape and one brand of PUE fiber showing the positive patch test reaction at the concentration of 9150 and 3110 μg/g, respectively. In addition, another brand of PUE fiber with the negative patch test reaction contained Tinuvin 327 (3230 μg/g) and Tinuvin 328 (3200 μg/g). From these results, it was clarified that Tinuvin P in the PUE tape used in the causative T-shirt was a causative chemical in this case and Tinuvin P was present in a brand of commercially available PUE fibers.

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In order to elucidate the mechanisms of mutagenic activation of nitrobiphenyls in Salmonella typhimurium TA98 by use of a mammalian activation system, 2, 4, 6-trinitrobiphenyl (TNBp, 0.09 rev./nmol+S9) and 2, 4, 2', 4'-tetranitrobiphenyl (TNBp^*, 457.19 rev./nmol+S9) were incubated with 10% S9 mix, separately, and their mutagenic metabolites were separated by SiO₂ and Al₂O₃ column chromatography. In 2, 4, 6-TNBp, 4-amino-2, 6-dinitroBp (0.11 rev./nmol-S9) and 2, 4-diamino-6-nitroBp (0.50 rev./nmol-S9) were isolated from the reaction mixture of TNBp with S9 mix at 37°C for 48 h, and their structures determined by their mass and ¹H-NMR spectra and the GC/MS data of their deamination products. In 2, 4, 2', 4'-TNBp^*, 2, 4'-diamino-2', 4-dinitroBp (25460.01 rev./nmol-S9) and 2, 2'-dinitrobenzidine (33.79 rev./nmol-S9) were isolated from the reaction mixture, and their structures also determined by their physico-chemical and the GC/MS data of their deamination products. From the high-performance liquid chromatographic analysis of these metabolites, the mutagenicity of 2, 4'-diamino-2', 4-dinitroBp (-S9) contributed 100% of the mutagenicity of 2, 4, 2', 4'-TNBp^* (+S9), whereas the mutagenicity of 4-amino-2, 6-dinitroBp and 2, 4-diamino-6-nitroBp contributed only 0.8 and 0.4% of that of 2, 4, 6-TNBp (+S9), respectively. Mutagenicity of 2, 2'-dinitrobenzidine was reduced to a half by the treatment with S9 mix, whereas the mutagenicity was expected to be enhanced by a mammalian metabolic activation system.

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Contamination of groundwater by volatile chlorinated hydrocarbons is a serious problem today all over our country. In this paper, the adsorptive removal of trichloroethylene (TCE), one of the major contaminants, onto activated carbon fibers (ACFs) in liquid phase was investigated focusing on adsorption isotherms. The adsorption capacity of ACF was larger than that of granular activated carbon (GAC). The adsorption isotherms of TCE onto ACFs and GAC were of Freundlich-type. The amount of TCE adsorbed was inversely proportional to the pore volume, the specific surface area of ACFs, as well as the amount of water adsorbed onto ACFs in gaseous phase. It is considered that the more hydrophobic is the surface of ACF, the larger is the amount of TCE adsorbed onto ACFs in liquid phase.

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A method for the quantitative determination of oxine-copper [bis (quinolin-8-olato) copper], a fungicide used widely in golf links, in water was developed. Oxine-copper was extracted from the sample water with dichloromethane. The dichloromethane solution was evaporated to dryness. The residue was dissolved in methanol and the solution analyzed by high performance liquid chromatography. The analytical conditions were as follows : column, Inertsil ODS-2 equipped with ceramic filter (GL Sciences, 5 μm, 250 mm×4.6 mm i.d.) ; mobile phase, acetonitrile-50 mM phosphate buffer [pH 3.5, containing 0.1% ethylene-diaminetetraacetic acid disodium salt] (EDTA-2Na) (40 : 60, v/v) ; flow rate, 0.8 ml/min ; detection wavelength, 240 nm. Under these conditions oxine-copper was converted to 8-hydroxyquinoline by EDTA added to the mobile phase, and the resulting 8-hydroxyquinoline determined quantitatively. The calibration curve for oxine-copper was linear in the range of 1-100 ng. The minimum detectable amount of oxine-copper was 0.1 ng. This method is widely applicable to the determination of trace amounts of oxine-copper in water.

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