Anaerobic digestion system had been used in Japan for treatment of night soil, collected by vacuum cars, but this method produced many complaints of bad odor. Recently, standard method of treatment was designated by the Goverment, classified to three methods of anaerobic, aerobic, and physicochemical methods. Many newly constructed plants adopted the aerobic system. The aerobic treatment method is reviewed in this article ; history of night soil treatment, components of raw night soil, microorganisms found in night soil and the plants.

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A method for tertiary treatment of night soil by chlorination with calcium and sodium hypochlorites was studied. Removal of ammonium-nitrogen by hypochlorite was not affected by pH. When an excess of hypochlorite to the break point was added, color and ammonium-nitrogen were completely removed. To eliminate the color, the most effective pH on chlorination was at 1-2. Colored substances in the secondary treated water of night soil, such as humic acid, fulvic acid, hymatomelonic acid, and methanol and water-soluble substances, were easily decolorized by chlorination. Orthophosphate was effectively removed by flocculation at pH 10 or above. Orthophosphate was completely removed by treatment with calcium hypochlorite. But, when sodium hypochlorite was used, calcium hydroxide must be added in order to eliminate orthophosphate. The two-stage pH adjustment method is the most effective for the tertiary treatment of night soil by chlorination.

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The liver of Cyprinus carpio was capable of metabolizing benzo [α] pyrene to 3-hydroxybenzo [α] pyrene. The enzyme system, localized in the 105000×g sedimented pellet (microsomal fraction) of liver homogenate, has an absolute requirement for NADPH, and a partial requirement for MgCl₂. The enzyme activity was detected in the liver and kidneys, but not in the gill, intestine, heart, or spleen of the fish. The enzyme was inhibited by KCN, NaN₃, cytochrome c, and SKF 525-A, which are known to be the inhibitor of hepatic monoxygenase in mammals. It was also strongly inhibited by 7, 8-benzoflavone and vitamin A which are known as inhibitors of the mammalian cytochrome P 448-linked oxidative enzyme system.

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A method was developed for the determination of nonionic polyoxyethylene surfactants in low concentration (0.2-1.0 ppm) by atomic absorption spectrophotometry. This method is based on the bismuth contained in the precipitate which is produced by nonionic polyoxyethylene surfactants and modified Dragendorff reagent. It was possible to determine 0.02 mg of the surfactant in 11 of the sample when the foam separation method and ion-exchange resin column chromatography were used for the concentration and purification of the sample. The sensitivity of this method is about 10 times higher than that of ammonium tetrathioisocyanatocobaltate. This method was used to detect nonionic polyoxyethylene surfactants in the waste water from apartment houses.

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Examination was made on the simplified determination of a microquantity of sulfur dioxide in the atmosphere, using ordinary temperature collection and gas chromatngraphy. It was thereby found that the best method of sampling was suctional collection of the air into a Pyrex glass tube filled with 0.5-1g of porous polymer beads (Tenax GC) and suction of the air for 2-4 min at the rate of 20-50 ml/min, at ordinary temperature. For the determination of collected components, the Tenax GC beads are heated to 250°and the gas evolved is introduced into the gas chromatograph equipped with a flame photometric detector, consisting of a seperation column soaked in Chromosorb T filled in a Teflon tube (3.2 mm×2 m), with polyphenyl ether (5 rings) and 0.5 g of phosphoric acid and 12 ml of acetone. Collection of sulfur dioxide by the above method was found to be 100%, and recovery rate was over 95% at the coefficient of variation of 0.6-6%. The limit of detection was ca. 2 ppb with 100 ml of the test air collected. Stability of the sample was good, and there was no loss of sulfur dioxide even when Tenax GC beads were maintained at room temperature for 9 hr. The collection and analytical procedures of this method are simple, require only a short period of time, and analytical precision is good, so that this method is thought to be a useful method for the measurement of a microquantity of sulfur dioxide in the atmosphere. A good result was obtained by comparison of this method with automatic measurement of sulfur oxides in the actual environment.

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A simple method for measuring beryllium in environmental materials was investigated by the use of flameless atomic absorption spectrophotometer equipped with a graphite tube atomizer. Nitric acid was suitable for decomposing environmental materials such as precipitator dusts which were exhausted from refuse incinerators. Furthermore, 2 to 10 N nitric acid concentration stabilized absorbance of beryllium, and eliminated background absorptions of sodium, potassium, and calcium when the charring temperature was set at 900°. Background absorption caused by less than 1000 μg/ml of aluminium, sodium silicate, manganese, magnesium, and iron could be corrected completely by using a deuterium are lamp as a background corrector. As the atomic absorption signal of beryllium was interfered by aluminium, calcium, iron, sodium silicate, and zine, which are commonly present in the dust, a method for standard addition should be used to correct these interventions. By this method, beryllium in precipitating dust can be analyzed without any separation procedure. Beryllium content in the dust of electric precipitators and multicyclones averaged 0.17 and 0.43 μg/g, respectively. Beryllium in them scarcely dissolved in water.

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Odorous Compounds in a Blue-green algae, Oscillatoria sp. and the sorrounding water collected at the Saka river, an upper stream of the Edo river were examined by gas chromatography-mass spectrometry. The compounds were separated from the algae by steam distillation, and from the water by solvent extraction with dichloromethane and by subsequent column chromatography using Amberlite XAD-2. 2-Methylisoborneol, geosmin, p-cresol, indole and 3-methylindole were confirmed both in the algae body and the river water. Saturated aliphatic hydrocarbons (C₁₁-C₁₅, C₁₇) and heptadecene were also identified in the mass of the algae.

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The accumulation of 2, 6-diisopropylnaphthalene (2, 6-DIPN) in various tissues of male and female rats was investigated by feeding a diet containing 0.1 or 0.2% 2, 6-DIPN for 14-31 days. The 2, 6-DIPN contents in the blood, liver, kidneys, and adipose tissue were increased in proportion to the dose, but were not affected by the difference in administration periods. The 2, 6-DIPN content in the adipose tissue was much greater than that in the other tissues. In addition, the 2, 6-DIPN contents in the blood, liver, and kidneys were markedly decreased in the case of administration of the control diet for 24 hr after feeding of the experimental diet for 17 or 31 days, but the decrease of 2.6-DIPN content in the adipose tissue was only 10-30%. In the case of administration of the control diet for 7 days after feeding of the experimental diet (0.1% 2, 6-DIPN) for 14 days, 2, 6-DIPN completely disappeared from the blood, liver, and kidneys. However, 2, 6-DIPN was detected in the adipose tissue and skin even when the control diet was fed for 28-35 days after feeding of the experimental diet for 14 days.

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A rapid, simple, and accurate colorimetric method with hematein reagent was established for the determination of a trace of tin in canned juice. The sample was prepared by digesting 1.0-5.0 ml of canned juice with a mixture of sulfuric acid-nitric acid. To 0.2-1.4 ml of the sample, 0.1 ml of 10% tartaric acid and one drop of 1% phenolphthalein were added. After neutralization with alkali, 2 ml of 20% sulfuric acid and 2 ml of 1% acacia were further added. This mixture was diluted to 15 ml with water, and 5 ml of 0.3% hematein reagent was added and mixed well. This mixture was allowed to stand for 40 min at room temperature, and then was further diluted to 40 ml with 0.5% sulfuric acid. Absorbance of this solution was determined at 560 nm against the reagent blank. Under the above condition, tin content in two kinds of canned juice was determined with a recovery of 94-111% and coefficient of variation of about 5%. A more rapid method by the addition of hematein reagent directly without digestion of the sample juice was examined, and results obtained with canned orange and apple juice were very satisfactory, with a recovery of 96-109% and coefficient of variation of about 4%. The time required for determination of tin by this method was about 1 hr for 10 samples.

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