In order to analyse oxidized sulfur compounds in air, determination of sulfate in rain water is important. For this purpose, it is necessary to analyse many samples containing a small amount of sulfate. Previously, a microbiological assay of sulfate in water using cultivation of Escherichia coli B was developed by Omura. We applied Omura's method on our object and defermined sulfate in rain water using Escherichia coli B (H). The standard curve was established by measuring turbidity of the culture medium, and showed lineality in the range from 0 to 12 ppm of sulfate. The amount of 0.5 to 20 ppm of sulfate in rain water was determined by this method with an accuracy of standard deviatio n<±3%.

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River pollution by pig farm waste and self-purification were investigated at Ishiuchi river in Hiroshima Prefecture. Following results were obtained. 1) BOD value of pig farm waste water discharged to Ishiuchi river was x^-=4029 (±2059) ppm. Volumes of discharged waste at point No. 2 were 0.002-0.005m³/sec, and the amounts of flow of Ishiuchi river at point No.2 were 0.03-0.21 m³/sec. Self-purification in this river was consisted of three steps : BOD removal by sedimentation, by biochemical process and oxidation of nitrogen compound. 2) Relationship between the amount of flow and self-purification in the river was observed in strongy polluted area. During the rainy season, effect of BOD removal might be raised as compared with that of draught season. Main factor of this phenomenon might be sedimentation of SS. 3) After the completion of SS sedimentation, self-purification was not affected by the amount of flow of the river. 4) Velocity of the BOD removal especially by biochemical process, which was one of the self-purification process in the river, was accerleated up to show the highest value after almost completed sedimentation of easily precipitable SS in strongly polluted area. 5) It is reasonable that self-purification in the river polluted with organic waste should be considered from the standpoint of oxygen balance. According to this consideration, rate of BOD removal in waste being discharged to Ishiuchi river might be required to be 90%.

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A new modified method for the spectrophotometric determination of carboxyhemoglobin was devised. Normal blood samples from 50 subjects including 20 no smokers were analyzed, and the coefficinent C which is the mean ratio of absorbance of carboxyhemoglobin to oxyhemoglobin at 419 mμ was experi-mentally determined. The following equation for the calculating of the concentration of carboxyhemoglobin was derived from the application of the coefficient. X (%)=131×(1.76×Ex/E₁₀₀-1) In this equation, Ex is the absorbance at 419 mμ of a blood sample diluted to 2000 times, and E₁₀₀ is the one of the same diluted blood saturated with carbonmonoxide. The technique of saturating carboxyhemoglobin was improved in the method. Dilution of blood sample with carbonmonoxide water showed better results in the point of saturation of carboxyhemoglobin and its deviation than the usual method blowing carbonmonoxide gas into diluted blood. It was also demonstrated that the change of the absorption spectrum and the decrease of the maximum absorbance of carboxyhemoglobin are caused by blowing enormous volume of gases such as oxygen, nitrogen and carbondioxide.

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The official method for the determination of Cl^- and SO^2-₄ in food coal-tar dyes gave low results because of the adsorption of significant amounts of the ions on activated charcoal. Automatic potentiometric titration method, which the titration stopped automatically at a setting potential, was applied to the determination of Cl^- in the dyes. The condition of electrode potential having a constant value at the end point was examined, and Cl^- was automatically determined rapidly and simply with less than 1% error. SO^2-₄ in azo and triphenylmethane dyes was separated from the dyes by extraction with Amberlite LA-2 and determined with less than 2% error by chelate titration method with EDTA after adding excess barium nitrate. SO^2-₄ in Acid Red was directly determined with less than 2% error by chelate titration method using potentiometric end point detection, because it was found that the dye containing sulfonic acid groups in the molecule was not precipitated by Ba²⁺.

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A T-shaped long absorption tube was applied to the atomic absorption spectrophotometric analysis of tin. The horizontal part of the absorption tube has a length of 50 cm and an internal diameter of 1.2cm. A sample is directry injected into an air-hydrogen flame by Jarrell-Ash Hetco atomizer burner, and light absorption of tin is measured at 2863 A. Employing the absorption tube, the linearity of calibration curve for tin was held in the range from 0.1 to 1.0 μg/ml, and the the limit of detection (1% absorption) was lowered to 0.02 μg/ml. The relative standard deviation was less than 3.4% at levels between 0.5 and 1.5 μg/ml. As a result of studies on interference, many substances were found to have a depressive effect on tin absorption, when present in more than a certain concentration. The date of analysis on canned fruit juices were in good agreement with those obtained by polarography.

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Behavior of chromous and chromic ions in the atomie absorption spectroscopy was investigated in neutral aqueous solutions and various acid solutions in the presence, and absence, of sodium sulfate, using air-hydrogen and air-acetylene flames. In 0.1-1 N sulfuric acid solution containing 60-4000 ppm sodium sulfate, both chromium ion exhibited the same and constant sensibility and the maximum sensibility was obtained under the conditions as shown below ; Flow rate : air 8.0 liter/min, acetylene 2.8 liter/min and burner height : 5 mm. These results were applied to determination of chromium in food coal-tar dyes and a simple and rapid method for analysis were established.

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A rapid and convenient method for the determination of microamount of lead in foods and pharmaceuticals by atomic absorption spectrophotometry was described. The absorption tube 50 cm in length was used to improve the analytical sensitibity for lead. The samples were decomposed by the oxygen bomb method, and the combustion products were dissolved in 0.1 N nitric acid. pH of the solution was adjusted to 9-10, and the lead chelated with APDC (ammonium pyrrolidine dithiocarbamate) was extracted into chloroform. The chloroform solution was sprayed into the absorption tube by a mixture of air and hydrogen, and the absorption of lead was measured at 2833 A. Experimental conditions such as analytical lines, extraction of APDC-Pb complex into chloroform and the influence of coexsisting elements, were examined and the optimal conditions for the determination of lead were established. The linearity of calibration curve for lead was maintained in the range from 0.05 to 1.2 μg/ml. In the recovery test, mean value of recovery of lead added to glucose at levels between 5 and 15 μg was 93.0%. The analytical results obtained by present method for lead contained in polished rice, green tea and P. V. P. (polyvinylpyrrolidone) agreed well with those found by other methods including polarography.

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The determination of microamount of arsenic by atomic absorption spectrophotometry using absorption tube was described. Air-hydrogen flame, having low background absorption at 1937 and 1972 A for arsenic resonance lines, was able to be obtained by forcible exhaust of the flame gases from near the end of the absorption tube. Using this flame, operating conditions, sensitivity, interfering substances and determination of arsenic in foods were investigated. The calibration curves at two arsenic resonance lines were straight up to 1.0 μg/ml of arsenic, and the sensitivity (concentration giving 1% absorption in aqueous solution free from interfering substances) at 1937 and 1972 A were 0.02 and 0.03 μg/ml of arsenic, respectively. Sulfuric acid, glucose, sodium chloride and many other substances interfered remarkably the determination of arsenic, but only hydrochloric acid in the range of 0.01-1.0 N did not interfere. The determination of arsenic in foods could be facilitated by the extraction of arsenic with iodide-benzene system followed by re-extraction process from the organic phase. The results of analysis were in good agreement with those obtained by other methods.

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The self-purification ability of river water was investigated on the two rivers in the northern parts of Kobe city, and the following results were obtained. 1. While the river water of the Arima goes about 4.5 km downstream, the COD and BOD value were decreased by 78.0% and 83.3%, respectively. 2. For increasing BOD value, a definite amount of glucose was added in the river water of the Shijimi. While going about 4.5 km downstream, the BOD value and glucose amount were decreased by 63.9% and 72.7%, respectively. 3. According to the measurement of the decrease of glucose amount in the river water by jar test, it was proved that 15 m³ of air were consumed to decompose 1 g of glucose.

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Concentration of sulfur oxides and nitrogen dioxide in atmosphere was measured by alkaline filter paper method in summer (June 1968) and winter (January 1969) at 100 places in Kyoto, including the grounds of shrines and temples in which the designated Important Cultural Properties were placed. A rather higher concentration of both sulfur oxides and nitorogen dioxide was generally observed in winter than in summer. Further effect of these air-pollutants on metallic luster of these Properties was investigated, and the rate or decrease in metallic luster was about 10% lower on the average in winter than in summer. Although it was supposed that the weather conditions might be largely responsible in decreasing the metallic luster, correlation between the concentration of sulfur oxides and the rate of decrease in metallic luster was observed generally in both summer and winter (correlation coefficient found, 0.458 in summer, 0.416 in winter). There was no correlation between the concentration of nitrogen dioxide and decrease in the luster of metals (correlation coefficient found, 0.180 in smmer, 0.138 in winter).

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