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The excretion and the uptake of Ca in rats were investigated in detail after the oral administration of CdCl 2 for various periods of time. The rats which had been pretreated with CdCl 2 for 1 month excreted 55% of orally administered 47 Ca in feces, whereas the rats which had not been pretreated with CdCl 2 for the same period excreted only 20% of the orally administered 47 Ca into feces. These facts indicate that the absorption of Ca from the gastrointestinal tract was lowered by the exposure of rats to Cd. Most of the excreted 47 Ca was found in feces, even when Ca was administered iv. Thus, the rats which had been pretreated with CdCl 2 for 3 months excreted 80% of the iv administered Ca into feces. Furthermore, the uptake of iv administered 47 Ca into bones was found to decrease up to 30% by the pretreatment of rats with CdCl 2 for 3 months. These observations support the hypothesis that Cd is one of the important factors in the development of the so-called “itai-itai” disease, which is a form of osteomalacia and an endemic disease in Cd-polluted areas in Japan.

Fundamental studies were carried out on the removal of polychlorinated biphenyls (PCB) contained in polluted source of supplying water. Activated carbon and coagulants such as aluminium sulfate and polyaluminium chloride (PAC) were used for removing PCB from water. In the present work, method for determination of PCB was also studied. Gaschromatographic determination of decachlorobiphenyl (DCB), which was obtained by complete chlorination of PCB with SbCl5, gave a good result. Among several preparations of PCB, Kanechlor-600 in water was determined as DCB in a good yield by gaschromatography, after extraction with n-hexane, concentration with Kuderna-Danish condenser, and chlorination with SbCl5 in a sealed glass tube at 200°for 1 hr. Removal of PCB from water was tested with Kanechlor-600 usnig the above method of determination. Two processes of treatment for aqueous solution containing 1ppm of Kanechlor-600 showed about 90% removal. One of them was the addition of activated carbon powder and coagulant at the same time, and the other was to pass the solution through a column of granular activated carbon. These processes were used in the purification system of water supplying work in some instances. It is considered that such higher purification system will be effective in removal of PCB from polluted water.

In order to examine the effect of multi-stage flash distillation on the conversion of polluted sea water, fundamental experiments and quality test of fresh water were carried out. The plant used in this study was a coal mining company in Ikeshima, Nagasaki, and has a distilling capacity of 2650 ton/day. The results were as follows : 1) It was possible to prevent the NH3-N distillation completely when the pH value of sea water was adjusted to 4.0 with sulfuric acid. 2) Efficency of purification of sea water by this plant was excellent, but total hardness, Cl-, PO3-4, and metaphosphate of supply water were higher than those of total distilled water, because of the addition of metal-masking reagents and brine water in this supply water.

The present series of work was undertaken to prove that there is no possibility for the presence of either ferulic acid or p-hydroxycinnamic acid in purified city water supplied by authorized water works. Both ferulic and p-hydroxycinnamic acids consume chlorine and are rapidly decomposed. They consume about 4 moles of hypochlorite for each mole of the substance, and the reaction is completed when the residual chlorine detected in the reaction mixture becomes about 0.1 ppm or less. This test for ferulic and p-hydroxycinnamic acids was carried out because some investigators attributed the incidence of a chronic bone disease, the so-called Kaschin-Beck disease, to city water, even if supplied by qualified water works, because of the presence of p-hydroxycinnamic (p-cumaric) and 4-hydroxy-3-methoxycinnamic (ferulic) acids, which were reported to have been detected in polluted river water used as a source of city water and which were found to produce changes in the cells of artilage tissue and salivary grands in young rats.

To confirm air pollution caused by automotive exhaust gas, it is necessary to know its relation to traffic densities and amount of air pollutions. Measurements of carbon monoxide, sulfur dioxide, nitrogen oxides and dust particles contained in atmosphere were carried out at Kasumigaseki and Itabashi, heavy traffic area in Tokyo, from Jan. to Dec., 1964 to explain the correlation between traffic densities and air pollution in urban atmospheric pollution. Concentrations of carbon monoxide and sulfur dioxide has a high degree coefficient of correlation to traffic densities, especially the concentration of carbon monoxide marks out the pollution caused by automotive exhaust gas in the atmosphere. From the correlation of traffic densities and resulting pollutants, we can presume the degrees of air pollution in future caused by automotive exhaust gas. The correlation between traffic densities and amounts of nitrogen oxides in atmosphere is not so remarkable. The amount of dust particles was partially varied with the other factors, such as meteorological and geographical conditions.

For the purpose of comparing air pollution in urban and rural area by the automotive exhaust gas, Pb concentration in the hair of regional inhabitants was examined and the following results were obtained. 1. In the determination of Pb in hair, it was found that the amount was larger in female than in male. 2. As for the difference in Pb concentrations by regions, the average and maximum values were larger in inhabitants in Tokyo than those in rural areas. 3. As for the difference in Pb concentrations by occupations, the average and minimum values were larger in traffic policemen in Tokyo than in men of other occupations in the same city.