In order to find the mercury content levels in normal maternal body and newborns, total mercury and methylmercury contents in maternal blood, hair, placenta, umbilical cord, and umbilical cord blood (newborn blood) were examined. In 89 normal women after delivery, living in Nagoya City, the following results were obtained. Total mercury and methylmercury contents were 1.83±0.91 and 0.93±0.56 μg/100g, respectively, in maternal blood, 2.57±1.03 and 1.77±0.72 ppm, respectively, in mother's hair, 9.07±9.34 and 1.07±0.96 μg/100g, respectively, in placenta, 2.36±2.89 and 0.72±0.54 μg/100g, respectively, in umbilical cord, and 2.67±1.20 and 1.56±0.95 μg/100g, respectively, in umbilical cord blood. Both total and methyl-mercury contents in umbilical cord blood (newborn blood) were apparently higher than in maternal blood, and it seems that mercury compounds transfer through placenta to the fetus and accumulate there.

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In order to study the placental transfer of mercury compounds and their accumulation in fetus in normal maternal body, total mercury and methylmercury contents in maternal blood, placenta, and umbilical cord blood were examined in 89 women after normal delivery, living in Nagoya city, and the following results were obtained. 1) In methylmercury content, there was a highly significant correlation between maternal blood and placenta but highly significant correlation was not found between them for total mercury content. 2) There was highly significant correlation in methylmercury content between placenta and umbilical cord blood. 3) There was a highly significant correlation in total mercury and methylmercury contents in blood, between maternal blood and umbilical cord blood. It was concluded that mercury compounds, especially methylmercury compounds, transferred through the placenta to fetus and accumlated there, and that higher intake of mercury compounds into the maternal body resulted in the higher mercury content in umbilical cord blood.

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To examine the distribution and status of Cu, Cr, Pb, Zn, Cd, and Ni in the mud of Tsurumi River, surface mud samples were collected at 8 stations from the mouth to up the river. Total heavy metals of mud in the upper and middle part of the river showed values near the mean of heavy metals in Japanese rivers of the first category. Ethylenediaminetetraacetic acid (EDTA)-soluble Cu represented 30% of the total Cu, while Cd, Pb, and Zn 10 to 20% and Cr, Ni about 5%. Acid-soluble heavy metals were 10% higher than EDTA-soluble heavy metals. In the mouth of the river, near the Tsurumi industrial area, the total heavy metals were 2 to 6 times more than that in the upper and middle of the river. EDTA-soluble Cu and Cd showed about 60% of the total Cu and Cd, Zn and Pb about 70% and Cr and Ni 10 to 20%. Acid-soluble heavy metals were 10 to 20% more than that of EDTA-soluble metals. Therefore 1/2 to 2/3 of total heavy metals were extracted with 0.5 N HCl. These data indicated that a large portion of heavy metals in the mouth of the river came from industrial wastes and that such heavy metals can be extracted with 0.5 N HCl or EDTA.

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In order to evaluate the chlorinating effectiveness, inactivation of crystalline enzyme preparations was measured at various concentrations of hypochlorite, hypochlorite-isocyanuric acid mixture, and chloramine. Urease inactivation occurred at the same rate by the three different chlorine preparations. Trypsin was inactivated similarly by hypochlorite and hypochlorite-isocyanuric acid mixture, but not by chloramine. In the case of alcohol dehydrogenase, chloramine reacted more effectively than hypochlorite, and hypochlorite-isocyanuric acid mixture was more effective than the other two. In the present work, added chlorine was consumed entirely by the enzyme solution within 1 min. Therefore it is apparent that the difference in the degree of enzyme inactivation among these chlorine preparations cannot be due merely to the difference in the amount of chlorine actually reacting with each enzyme. This fact implies that the mode of reaction between chlorine and the active site of each enzyme differs among these chlorine preparations.

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Determination of phenols with 4-aminoantipyrine is stated in the Standard Method of Analysis for Hygienic Chemists authorized by the Pharmaceutical Society of Japan and in various standard methods. This method is not evident from the viewpoint of the applicability for determination of various phenols, and the meaning and evaluation of results obtained by the method. Therefore, comparison of color development of phenol derivatives with 4-aminoantipyrine, reactivity of phenols with free residual chlorine, and the effect of reactants on the formation of antipyrine dye were examined. Results of recovery tests and intensity of color development using phenol derivatives indicated that this method can measure at ppm levels phenol derivatives such as o- and m-cresols, o, m-, and p-chlorophenols, dichlorophenols (except 2, 3-, 3, 4-, and 3, 5-dichlorophenols), p-bromophenol, o-, m-, and p-methoxyphenols, and o-allylphenol in city water and fresh water. The relationship between absorbance at 460 nm and phenol derivative concentration showed liniality below 80 μg of phenols. Concerning the effect of reactant phenol derivatives and free residual chlorine on the formation of antipyrine dye, phenol showed decrease of absorbance at 460 nm with increasing concentration of free residual chlorine and length of reaction time. Phenol derivatives have three patterns of changes ; rapidly decreasing, nonchangeable, and slightly increasing.

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In continuation of the preceding work on the water quality of the moat around the Imperial Palace in Tokyo, which is considered important as source of drinking water during emergency, yearly changes in the quality of moat water were measured and detailed examinations were made of the moat in two places during August, 1974. The moat was divided into five or six sections of equal distance, and water was sampled from upper and lower layers of each section. Laboratory tests were also made on removal of nutrients from moat water by filtration. It was thereby found that the quality of moat water did not differ greatly among sampling stations, and between upper and lower layers, so that measurement would be sufficient by sampling at one or two stations in each moat. Characteristic pattern of water quality was the high correlation between DO and pH, and this was especially so in November when the correlation coefficient was γ=0.765 and the regression line, Y=4.962X+0.272. Filtration was found to remove over 50% of total nitrogen, total phosphorus, and COD, and that removal of phytoplanktons from the moat will decrease nutrients in the moat water.

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Comparative studies were made on the bactericidal effect of hypochlorite, hypochlorite and isocyanurate, and chloramines. Survival of Escherichia coli exposed to hypochlorite for about 15 sec was not affected by the addition of 30 ppm of isocyanurate. In contrast, chloramines required 4-6 times of available chlorine concentration to obtain the same effect as that of hypochlorite, or 3-5 times longer exposure with the same concentration of chlorine.

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The"Standard Methods of Analysis for Hygienic Chemists"authorized by the Pharmaceutical Society of Japan (published in 1973) prescribe the use of acetanilide as an internal standard for the gas chromatographic determination of dehydroacetic acid, sorbic acid, benzoic acid, and esters of p-hydroxybenzoate, using the FID gas chromatograph fitted with columns packed with 5% DEGS+1% H₃PO₄. When only the three preservatives (sorbic acid, dehydroacetic acid, and benzoic acid) have to be examined in one sample (such cases are often encountered), the retention time of acetanilide seems to be too long compared with those of the three preservatives. Moreover, the broad peak of acetanilide might make it impossible to carry out an accurate determination of the three preservatives. Accordingly, replacement of acetanilide with another suitable internal standard was examined and p-toluic acid was finally chosen as the new internal standard. The use of p-toluic acid increases the measurement accuracy of the three preservatives by three times.

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Quaternary ammonium chloride is being used increasingly to give a glossy appearance on the surface of bamboo sheath, which is used as a food wrapping. Extraction of this quaternary ammonium chloride is rather difficult because it may have combined with some constituents of the bamboo sheath. A method was therefore devised to isolate and determine the quaternary ammonium chloride. Bamboo sheath is cut into small pieces, heated with 0.1 N HCl for 30 min, and then the acidic solution is extracted with two 30 ml portions of ethanol. Ethanol is steam distilled from this extract and quaternary ammonium chloride in the residual aqueous solution is determined by the Bromophenol Blue method, the amount being expressed as mole of benzethonium chloride.

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The usual method of preserving the samples for NO₂-N analysis in a strong acid condition was found to be unsuitable because NO₂-N decreases with time. This decrease rate after 24 hr was found to be 3% at pH 4.0, 22% at pH 3.5. and 55% at pH 2.0 for 20.0 ppm of NO₂-N. Decrease rate of NO₂-N at pH 2.0 was found to be different according to its initial concentration. The rates after 27 hr were 9.5% with 2.0 ppm of NO₂-N, 30.5% with 10.0 ppm, 34.5% with 20.0 ppm, 28.0% with 50.0 ppm, and 25.5% with 100.0 ppm of NO₂-N. NO₂-N in water and wastewater did not change by the addition of 40 mg/liter of HgCl₂, 5 ml/liter of CHCl₃, or 5 ml/liter of CH₂Cl-CH₂Cl. When NO₂-N is to be analyzed within 24 hr of sampling, it is recommended that the sample be preserved at 5°.

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For the purpose of establishing a sensitive method for the determination of streptomycin in organic materials, the colorimetric method reported by Duda was investigated and the two main procedures in the original method were modified. With this modified method, 2.5-60 μg/ml of streptomycin in water was successfully determined and sensitivity of the method was twice that of the original method. The effect of protein coexisting with streptomycin on the colorimetry was examined. In lower concentration, protein suppressed the color development, and the absorbance in 1.5 mg/ml of albumin solution decreased the most and was as low as 80% of the control. On the contrary, in higher concentration of more than 6 mg/ml, protein promoted the reaction and the absorbance in 16 mg/ml of albumin solution was as high as 136% of the control. Thorough elimination of protein from the sample is therefore necessary to obtain an accurate streptomycin value in organic materials, but the technique is not yet established.

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The influence on the discoloration of two dyed clothes by nitrogen dioxide was measured. The apparatus of constant nitrogen dioxide generation was made in order to see the influence of nitrogen dioxide on the discoloration of dyed cloth. The nitrogen dioxide concentration is measured by NO₂ auto analyser. The dyed cloth is exposed to the nitrogen dioxide for a certain time in reaction chamber. For the detection of what extent the discoloration is occurred, the spectroreflectance (400-800nm) was used. In the dry air, the remarkable color fading and change of the materials did not happen. In the wet air (relative humidity 60%), the color of the silk cloth dyed with Acid blue 127 was only faded slightly and the color of the acetate rayon cloth dyed with Diacelliton fast brilliant blue B was faded and changed markedly.

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