In 1982, Dr Ito et al. reported that butyl hydroxy anisol (BHA : food additive) induced cancer for the forestomach of F344 rat. Four countries (Japan, United States, United Kingdom and Canada) and EC countries had meetings respectively and there experts evaluated the safety of all of the phenolic antioxidants including BHA. Each meeting concluded that as BHA could be a promoter the threshold might exist, and that the evaluation of the risks arising from the replacement of BHA was necessary. On the basis of the conclusions obtained at expert meetings, each country (excluding Japan) decided it unnecessary to take an administrative action on BHA. When a chemical was proved as a carcinogen in animal experiment, every government took an administrative action banning the chemical. However, BHA plays an important role in changing administrative principle on carcinogens. From now on, developed countries will adopt the evaluation system, based on estimating risk and benefit of a carcinogen, in taking an administrative action on it, and the studies concerning existence of threshold of a promoter and mechanism of development of cancer will be forwarded by each country.

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In order to investigate the effects of zinc on the contents of collagen and mineral in bone, femurs obtained from 9-day-old chick embryo were cultivated for 6 days in the presence of 58, 139 or 580μM ZnCl₂. Decreases in the contents of mineral and collagen were caused by zinc concentrations of 193μM and above. Zinc inhibited incorporation of ⁴⁵Ca into bone. Release of ⁴⁵Ca from bone was slightly inhibited by zinc. Zinc was shown to have an inhibitory effect on bone formation rather than on bone resorption. On the other hand, 27, 54 or 108μM zinc prevented a decrease in collagen content caused by cadmium, though zinc did not prevent a decrease in mineral content caused by cadmium. Cytosol obtained from zinc-treated bones was found to contain metallothionein-like protein, which might participate in zinc-induced tolerance to cadmium toxicity. These results indicate that the coexistence ef zinc at low concentrations with cadminm lowered bone mineral content but did not affect the matrix.

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A simple, precise and sensitive method for the determination of polyoxyethylene-type nonionic surfactants in water was established by using atomic absorption spectrophotometry with a graphite furnace atomizer. The proposed method is based on the atomic absorption spectrophotometric determination of cobalt in a chelate complex produced by the reaction of nonionic surfactants with ammonium cobaltothiocyanate reagent used in the spectrophotometric method of JIS K 3364 and K 0102. The interference by anionic and cationic surfactants could be removed by a cleanup procedure involving ion exchange resin column chromatography. The recoveries of polyoxyethylene-n-dodecyl ether as a standard compound in various environmental water samples were within the range of 93.0-111.3% and the coefficients of variation were within 9.0% ; these values are satisfactory. The proposed method does not require any preliminary concentration procedure because of the high sensitivity (detection limit : 0.001 mg/l). There was a highly significant correlation (γ=0.999) between the results obtained by the proposed method and those of the JIS K 3364 and K 0102 spectrophotometric method. The assayed values of nonionic surfactants in water samples obtained from 18 rivers were distributed between 0.001 and 0.895 mg/l.

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Metals in metallothionein and related metal-binding proteins in the soluble fraction of animal tissues were quantitatively determined by high performance liquid chromatography-atomic absorption spectrophotometry using ethylenediaminetetraacetic acid-metal complexes as internal standards. It was shown that peak areas rather than peak heights of metals have to be plotted versus internal standards and that the column has to be washed well with chelating agents to remove metals adsorbed on the column before application of internal standards.

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Instead of applying the glycerol coating method, the sample surface of a plastic food case was dipped with castor oil-ethanol solution (3%) and evaporated the solvent. Glass beads (50-75 mesh) stuck uniformly to the surface. As the glass beads weight was proportional to the surface area, the surface area could be determined by weighing the stuck glass beads. Spherical glass beads could be commercially obtained with ease and showed the good sticking ability. The accuracy and reproducibility of this method under several conditions were satisfactory. This method was suitable to determine the surface area of various plastic food cases.

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A rapid and simple procedure for the determinaion of methamphetamine and its metabolites in the rat urine was described by using gas chromatography with flame-thermoionic detector. The extraction procedure, the formation of heptafluorobutyryl derivative, the percentage recovery of the methamphetamine and its metabolites from the rat urine and the determination of methamphetamine metabolites in the rat urine were described. The sensitivity of methamphetamine and its metabolites by gas chromatography with flamethermoionic detector revealed that the detection limits of heptafluorobutyryl derivatives of methamphetamine and amphetamine were ca. 0.1 ng, p-hydroxyamphetamine and p-hydroxymethamphetamine were 0.14, 0.16 ng, respectively, norephedrine and p-hydroxynorephedrine were 0.26, 1.04 ng, respectively. In the rats, about 89% of the dose of methamphetamine (2.5 mg/kg, i.p.) and 74% of the dose of methamphetamine (5.0 mg/kg, i.p.) were excreted in the 2 days urine. The main metabolites excreted in the urine were p-hydroxymethamphetamine (56-47% of dose), p-hydroxyamphetamine (21-15% of dose) and amphetamine (2.7-3.3% of dose) in addition to the unchanged methamphetamine (9.0-8.6% of dose). The gas chromatography equipped with flame-thermoionic detector used for the determination of methamphetamine and its metabolites in the rat urine was satisfactory, and rapid, simple and highly sensitive method, and thus the method would be applicable for the determination of those drugs in the urine of the abusers.

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The mutagenicities of particles in automobile exhaust gas emitted under different driving conditions, i.e. constant speed driving (20, 40, or 80 km/h) and variable speed driving according to a typical traffic pattern in Tokyo, were studied. The gasoline-engined automobile was run on a chassis dynamometer. Exhaust samples collected on glass fiber filters, which were extracted with benzene, and the extracts were tested by the Ames Salmonella assay. Strains TA 100 and TA 98 were used, with and without a metabolic activation system (S9 mix). The mutagenic activity per km driving increased with increase of the speed, and the particles produced by variable speed driving showed higher mutagenicity than those produced by constant speed driving.

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The accumulation and clearance of mercury and selenium in the various tissues of rats injected with mercuric chloride and/or sodium selenite were studied. The concentrations of mercury and selenium in the blood of rats receiving both elements decreased with time and reached the blood levels of untreated rats about 56 days after dosing. Clearance rates of mercury and selenium in the liver and spleen were much lower when administered simultaneously than when administered alone. The same phenomenon was found on clearance rate of selenium in the kidney. However, the clearance rate of mercury in the kidney of rats injected with both mercury and selenium approximately agreed with that in the kidney of rats receiving mercury only between 14 and 112 days after administration. The molar ratio (Hg/Se) in the kidney of rats receiving both elements was much greater than 1 during the 112 days observation period. The results of this study indicated that the mercury and selenium accumulated in the various tissues of rats by the interaction of both elements were gradually eliminated.

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In order to clarify the variations of anionic surfactants level and BOD value in river water, the former was determined by the atomic absorption spectrophotometric method reported previously and the latter was determined by the testing method for industrial waste water described in JIS K 0102. Water samples were taken from three rivers close to Kobe Women's College of Pharmacy daily, except on Sundays and holidays, for one month. Both anionic surfactants levels and BOD values showed significant daily variations.

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It is well known that ion-specific electrodo method to determine fluoride in many kinds of samples such as water, industrial drainage, hot spring water and air is rapid, simple and accurate. However, an application of this method to determination of fluoride in foods is not investigated in detail yet. The results of reexamination which involve the analytical procedures of this method (i. e., digestion, distillation and determination) were described. By using the condition established here, it was found that fluoride in some kinds of foods could be conveniently determined with recovery 98.5-105.0% and coefficient of variation about 0.7%. Furthermore, fluoride contents in twenty six kinds of foods were satisfactorily determined by this method.

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