The wastewater of a chemical plant manufacturing acetaldehyde with mercurial catalyst had been emitted into the Suimon River in Gifu Prefecture. Monitoring surveys were made by measuring total mercury in bottom sediments from 124 sites in the Suimon River and the relevant rivers. The highest level, 180μg/g of mercury was detected at the site close to the outfall of the chemical plant and the mercury level ranged from the order of 10 to 10²μg/g at the sites downstream, whereas they represented the order of 10^-1to 10⁰μg/g at the sites upstream.
Therefore, the plant was proved to have been the source of mercury pollution of bottom sediments. The mercury pollution apperared to extend to the Makita River but not to the Ibi River. From the results of the survey of the horizontal distribution of mercury concentrations in sediments at 14 sites, it was found that the coefficient of variation of mercury concentrations in sediments from varied positions at a site reached 81.8% on the average, and mercury concentrations were generally lower in the centre of the channel but increased towards the shore. From the results of vertical distribution of mercury concentrations, a fairly regular relationship was obtained between depths of sampling positions and mercury concentrations. However, at some sites the relationship was observed to be inverse.

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Transport phenomena of contaminants is an interesting problem in the light of the water quality control of rivers. In a tidal river it is affected by the tidal oscillation. Observation data, however, often show the behavior which can not be explained only by the tidal oscillation. In such cases the effect of the secondary undulation which is often observed in the harbour and the canal opening to the sea may also have to be examined. It has been investigated for the sake of the prevention of disasters, but scarcely studied in the field o f water pollution research.
In this paper the effect of such tide induced motions on the water quality are discussed. The river flowing through Tokushima city was chosen as the site of the study, and the field survey was carried out. On the basis of the observation data the characteristics of the oscillatory motion of water is discussed in detail. Concerning the water quality variation, the importance of not only the tidal oscillation but also the secondary undulation is pointed out. Furthermore their effects on the water quantity and quality exchange are described.

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The painting waste water from a factory which had high concentrated zinc and nickel within it, was selected as a sample for foam separation treatment. In addition, model waste water contained zinc, nickel, magnesium, manganese and calcium was prepared like as the actual waste water. Then removing those ions from both model waste water were being studied by Foam Separation.
The three kinds of chelating reagents, DMDTC, DEDTC and SPDC were examined if they were effective as collectors for zinc or nickel from the model waste water and the actual waste water. F-W type mineral flotation machine was used as the Foam Separation apparatus.
Nickel and zinc could be removed selectively by DMDTC and DEDTC from both waste water, nickel and zinc could be removed from both waste water at the same time by SPDC.

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The well waters (sampling number 127) of the Tama area in Kawasaki City were analyzed for volatile chlorinated organic substances, such as trihalomethanes (THMs).
Small amounts of chloroform, I, I, I-trichloroethane, carbon tetrachloride, trichloroethylene and tetrachloroethylene are found in the well waters.
I, I, I-trichloroethane, tetrachloroethylene, carbon tetrachloride and chloropicrin, besides THMs, may be produced by chlorination of the well waters.
It is showed that volatile chlorinated organic substances formation potential by chlorination significantly correlated with KMnO4 consumption of the well waters, that is, KMnO4 consumption : TTHMs and KMnO4 consumption : chloroform.

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Surface sea waters were taken from June 1980 to November 1981 in the northern area of Hiroshima Bay. On shipboard they were each time incubated under the natural condition and the concentrations of chlorophyll a and POC were determined at about one hour intervals. POC_detri and POC_phyto were evaluated from the interrelationship between POC and chlorophyll a concentrations. POC_phyto/POC ratio ranged from 0.23 to 0.98 and the average value was 0.72.
In order to evaluate conveniently these fractions, a relationship between POC_phyto/POC and photosynthetic activity was studied. It was found that the former could be expressed as a natural logarithmic function of the latter.
Using this equation, POC_detri and POC_phyto of surface water in winter months and those of middle water were estimated. POC_detri/POC ratios of surface water in winter months were somewhat higher than those in other months. These ratios of middle water were generally larger than those of surface water.

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A simple and rapid method is presented for routine analysis of total nitrogen in environmental and waste water samples. Samples are taken into screw top glass bottles, and the bottles are closed with a teflon lined cap after addition of potassium peroxodisulfate and sodium hydroxide solution. After autoclaving at 121°C for 30min, samples are filtered or centrifugated if necessary, and acidified by adding sulfuric acid. Thus all nitrogen compounds in samples are quantitatively oxidized to nitrate. The absorbances at 220nm (A₂₂₀) and 240nm (A₂₄₀) are measured, and total nitrogen is determined by calculating the difference between both absorbances (A₂₂₀-A₂₄₀). The calibration curves of nitrate follow Beer's law and the applicable range is 0.05-5 mg/l as nitrate nitrogen.
When samples were digested completely, there would be no interference of organic chemicals. Moreover interferences of inorganic chemicals at levels occurring in waste waters were eliminated by subtracting A₂₄₀ from A₂₂₀. This proposed method was compared favourably with the Kjeldahl digestion method for river and waste water samples, and with the determination by T-N analyser for sea water samples.

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Aqueous solution of polyethylene glycol (PEG) was treated by ozone under UV irradiation (15 W lowpressure mercury lamp) at pH 2, 7 and 11. The degradation of PEG by ozone was enhanced by UV irradiation under all pH conditions. Under acidic conditions under which PEG was not degraded without UV irradiation, the UV light enhanced remarkably the consumption of ozone and the lowering of molecular weight but the TOC of the solution did not appreciably declined. The production of aldehydes by ozonization was enhanced also by UV irradiation under all pH conditions. Formaldehyde which is inhibitory to bactreria, however, was very small under neutral. UV irradiation enhanced exceedingly also the TOC decline under neutral conditions.

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