Instead of toxic sodium mercuric tetrachloride solution, triethanolamine (TEA) solution was used as an absorbent for the determination of sulfur dioxide in air. Absorption efficiency of TEA solution for sulfur dioxide was more than 99%, and the resulting sulfite ion was quite stable against aeration and solar irradiation. This procedure is carried out as follows : In an absorption tube, 20 ml of 1% TEA solution containing 0.001% sodium azide is place and the sample gas is passed through this solution at the flow rate of 11/min. To 10 ml of this solution, 2 ml of p-rosaniline formaldehyde reagent (0.04 g of p-rosaniline hydrochloride, 20 ml of hydrochloric acid, and 100 ml of 0.2% formaldehyde solution mixed and diluted with water to 200 ml) is added, allowed to stand for 35 min, and absorbance of the mixture is read at 560 nm. The presence of NO^-₃, Cl^-, S^2-, SO^2-₄, and NH⁺₄ (the molar ratio of each ion/SO₂ was 100) does not interfere in this determination but NO^-₂ showed negative interference, and this interference was completely removed by the addition of sodium azide to the absorption solution. Accuracy, reproducibility, and sensitivity of this method were the same as the usual p-rosaniline method (West's method).

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The concentration of PCB, Hg, Cd, As, Cu, Pb and Ni in the estuarial sediments of the rivers in Nagoya city were determined. The concentration of PCB ranged from 0.25 to 26.6 ppm and of the heavy metals exceeded those of the less polluted river sediments. Thus these sediments examined showed to be highly polluted by man's activities. The sediments were separated into 6 fractions of 500, 149, 105, 74, 62 and 62 μ>sizes by wet sieving analysis. The 149 μ fractions were composed of sand and coarse organic debris. In certain case, the amount of 149μ fraction exceeded that of 62 μ>fraction. The concentrations of PCB in the 149 μ fractions were higher than those in the 62 μ>fractions. However, in case of the sediment rich in gravel and sand, the reverse trend was recognized. The concentrations of heavy metals tended to be lower in the 149 μ fractions than 62 μ>fractions. These trends would indicate that PCB has a greater affinity for the coarse organic debris than the heavy metals. It was suggested that the distribution percentages of PCB and heavy metal contents to 149 μ fraction would depend on the qualitative and quantitative differences in the composition of the fraction. The floatabilities of sediments were examined in relation to the aggregate size distributions. It was confirmed that sediments rich in 149μ fraction composed of greater amounts of coarse organic debris or rich in the fine fraction of 62 μ>gave a large amount of suspended solids by agitation. In these cases, about 50% of PCB contained in the sediments were distributed into the suspended solids.

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The mechanism of the removal of night soil components by bacteria at the aerobic treatment plant of undiluted night soil was studied. For the removal of volatile fatty acids by bacteria iselated from this plant, E. coli. communior, B. megaterium, and propionic acid-utilizing bacteria were examined. Dissimilation rates for acetic acid and propionic acid by E. coli were 41.1% and 49.1%, respectively, but butyric acid was not used. From the removal pattern of these acids by E. coli, it was recognized that acetic acid inhibited the removal of propionic acid. Dissimilation rates for acetic acid by B. megaterium was 20.3% but propionic acid and butyric acid could not be used. In the case of propionic acid-utilizing bacteria, dissimilation rates for acetic, propionic, and butyric acids were 50.0%, 62.9%, and 38.2%, respectively. These rates were higher than those by E. coli and B. megaterium, and the speed of removal of propionic acid was higher than that of butyric acid by propionic acid-utilizing bacteria. In this plant, removal of substrates were carried out by all kinds of these bacteria.

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A method for the determination of cadmium in rat femur by flameless atomic absorption spectrophotometry was studied. The solution obtained by digestion of the bone with nitric acid and perchloric acid was applied to the Dowex 50 W×8 column, and cadmium was selectively isolated from calcium, phosphorus, and other elements contained in the bone by elution with 0.5N hydrochloric acid. This isolated cadmium was determined using the flameless atomic absorption spectrophotometer. The recovery of cadmium added to 1 g of commercial bone powder by this procedure was 98.0-116.5%, and good recovery of cadmium was also obtained in the range of 0.1-2.0 g of sample weight of the bone. By using this procedure, the content of cadmium in femur of male Wistar strain rats without artificial exposure to cadmium was determined, and the values were in the range of 0.03-0.08 ppm, and the avarage of 0.06 ppm in the bone.

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When the effluent from night soil treatment plant was chlorinated, chloroform was formed. The condition for chloroform formation and the substances that formed chloroform were examined. Mass of chloroform formed did not depend on pH, but was in proportion to the added calcium hypochlorite and to reaction time. Humic acid, fulvic acid, hymatomelonic acid, and methanol-water soluble substance were fractionated from the effluent, and all of the fractions formed 7-48 ppb of chloroform, chlorinated with 100 ppm calcium hypochlorite. Besides chloroform, humic acid formed C₂H₃Cl₃, C₅H₉Cl, and methanol-water soluble substance formed CH₂Cl₂, CCl₄, C₂H₄Cl₂, C₂H₃Cl₃, C₃H₂Cl₂, and C₆H₅Cl by chlorination.

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Kinetic studies on the inhibition of phospholipase A₂ (from Agkistrodon halys blomhoffii) activity with cadmium ion demonstrated that cadmium ion inhibits the enzymic activity competitively with respect to calcium ion and phosphatidylcholine. The Km value was 6.3×10^-3M for phosphatidylcholine and the Ki value of cadmium ion was 1.4×10^-4M, while, for the calcium ion, the K_m value was 2.8×10^-4M and K₁ value of cadmium ion was 1.4×10^-4M. Cadmium-metallothionein isolated from the liver of cadmium-injected mouse did not show any effect on the phospholipase A₂ activity and this fact suggests the protective effect of metallothionein against toxic effect of cadmium on lipid metabolism in living cells.

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Effect of cysteine on the transfer of mercury (methylmercury and inorganic mercury) compounds to fetus across the placenta was examined in pregnant rats. Either of 4 kinds of mercury solutions, methylmercury solution (MM), MM added with cysteine solution (MM-cys), inorganic mercury (HgCl₂) solution, and HgCl₂ added with cysteine solution (HgCl₂-cys), was injected intravenously into pregnant rats at 18 the day of gestation. After 2 hr, they were killed by blood letting from femoral vein and mercury concentration in blood, liver, kidneys, brain, placenta, and fetus was determined. In both placental and fetal mercury, MM-cys group showed significantly higher content that MM group but there was no difference between HgCl₂-cys group and HgCl₂ group. The ratio of fetal to placental mercury content in MM-cys group was significantly higher than that in MM group. These facts indicate that cysteine was one of the materials which promoted the transfer of methylmercury to fetus across the placenta.

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The formation ratios of reduction metabolites formed by R. glutinis and rat liver homogenate from 2, 3-, 2, 4-, 3, 4- and 2, 5-dinitrotoluene (DNT) were investigated. The reduction metabolites formed by both systems consisted of two kinds of monoaminonitrotoluenes and hydroxylaminonitrotoluenes from each substrate. The relation of major and minor products in the microbial system paralleled that in the mammalian system in vitro. The usefulness of the microbial system for metabolic and toxicological studies of DNTs is discussed. In addition, the formation ratios of the two monoamino compounds formed by both species were consistent with theoretical reactivity indices calculated by the molecular orbital method, suggesting that quantum chemical methods may be applicable to studies of the enzymatic reduction reactivities of DNTs.

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A rapid method for high-speed liquid chromatographic determination of micro amounts of estradiol or ethynyl estradiol in cosmetics was investigated. This method is based on the technique of direct dilution or solvent extraction of the samples by high speed liquid chromatography with octyl silane (LiChrosorb RP-8, 5 μ) as a stationaly phase, a mixture of acetonitrile-water as the eluent, and fluorescence spectrophotometer as a detector. The retention time of n-butyl-p-hydroxybenzoate in some creams that interfered in the determination was controlled by the addition of trioctylmethylammonium chroride to the eluent. Estradiol or ethynylestradiol in cosmetics at the level of 0.00015-0.00100% was determined by this method with a recovery rate of 93-103%.

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An improved determination system for arsenic was developed by using the apparatus of the hydride generator. The optimum concentration of reducing agents was 4-8 N hydrochloric acid, 0.1-0.5% potassium iodide, and 0.015-0.3% stannous chloride. Evolution of arsine was quantitative in the range of 40-75° of the zinc column. Sensitivity of this method for 1% absorption was evaluated to be 0.8 ppb of arsenic and a calibration curve obtained was linear up to 2.0 μg of As/50 ml. Coefficients of variation in the determination of 0.6 and 1.5 μg of As/50 ml were 3.9% and 2.35%, respectively, in the runs. The recovery of arsenic added to hot-spring, river, and sea water was 93-100%, with a relative standard deviation of 2.35%. Presence of most metal ions in the sample did not interfere in the determination of arsenic by this method, while selenium (IV), even at concentrations as low as an amount equal to arsenic, interfered in the determination of arsenic.

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