A novel device using optical fiber has been developed in order to measure the spectroscopic characteristics of sea water. The mechanism of this device is as follows.
1) The light passed through sea water is guided to the optical device by the optical fiber and the irradiance both just under the water surface and at certain depth of the sea is measured.
2) Absorbance (attenuance) is estimated from the irradiance determined at different depth of the sea. The spectra obtained by the present apparatus agree well with those by the conventional spectrophotometer. The result at cloudy weather is reliable, however, under clear sky with the seawater being transparent, the noise becomes remarkable. The noise originates from the fluctuation of the angle between the edge face of the optical fiber and the direction of the light in the sea ; this noise can be eliminated by covering the edge face with a ball of table tennis, by which the directivity of the light is relaxed.

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A precise and sensitive method was examined for the determination of beryllium in environmental sediments by electrothermal atomic absorption spectrometry. The ground sample was digested with HF/HNO₃/HClO₄, then beryllium was determined by standard addition method. Both use of a pyrolytic graphite-coated tube and addition of matrix modifier (0.4% aluminium nitrate) were effective in increasing sensitivity and precision. Constant absorbance was obtained in the charring temperature ranging from 1,200 to 1,700 °C.
Analytical results of beryllium obtained by proposed method showed in good agreement with the certified values for the environmental (sediments, rocks) reference materials.
In the presence of fluoride, the determination of beryllium by proposed method was seriously affected.
Beryllium concentrations in river, lake and marine sediments from Kanagawa prefecture, which obtained by digestion with HNO₃/HCl/HClO₄, were found in the range from 0.131 to 0.847μg·g^-1 (average 0.404μg·g^-1). These values were 17-71% lower values than the case of digested with HF/HNO₃/HClO₄.
The detection limit of the proposed metohds was 0.0013μg·g^-1 for 0.5g of sediment.

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A treatment of the wasted flower plants used for the waste water treatment process by the indoor drying and pressing method was studied for their effective reuse as columnar solid fuel. Three kinds of wasted flower plants were processed for making samples by indoor drying method for about two months. The samples which were chop plants about 10cm long, half powdery ones and powdery ones were made into the columnar solid fuels under 1-5 t·cm^-2 pressure.
According to the drop's strength test for the solid fuels, it was investigated that they lost their physical strength rapidly in proportion to the elaspsed time. The solid fuel made of powdery processed plants particularly lost its strength most lapidly.
In the case of solid fuels made of chops, when they were pressed by the method that the trunk and the branches filled into the press's vessel in the same direction against the press's one, their physical strength were maintained for a long time. Furthermore, the form of solid fuels processed by this method looked like keeping their original one for a relatively long term. It was found that their combustible efficiency was exellent because the combustible calorie of the wasted plants ranged from 3,600 cal·g^-1 to 3,800 cal·g-1.

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The purpose of this study was to examine the influence of turbid waters on phytoplankton biomass and flora in reservoirs. We examined water quality and phytoplankton in Tedori and Konade Reservoirs. Phytoplankton biomass increased and its flora changed when the turbidity of the lake waters reached about 20mg·l^-1 or above due to inflow of turbid waters or after that time. The flagellated chlorophytes, such as Pandorina, Carteria and Chlamydomonas, increased at that time. Concentration of T-P increased with the rise of turbidity (r≈0.8). From the relationship between T-P and D-P (dissolved T-P), it was considered that most of T-P was the insoluble type which was adsorbed on the mud particles in Tedori Reservoir. In Konade Reservoir, D-P was among the values from 0.004 to 0.012 mg·l^-1 in spite of the concentration of T-P, and Anabaena of cyanophytes, other than Chlamydomonas of flagellated chlorophytes, increased in the case of turbiditiy above 20mg·l^-1. It was presumed that the difference of flora at the turbidities above 20 mg·l^-1 between the reservoirs might be due to that of D-P concentration.

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The judgment of river water quality to the environmental standard is made based on 75% probability of BOD. The method recommended now by Japan Environment Agency is a simple one but is not accurate from statistical viewpoint. In this work, the following four analytical methods were examined with observed BOD in the report for environmental water quality of 1993 in Aichi prefecture : normal distribution, log normal distribution, and log normal distributions for the values subtracted the lower limit (estimated by Iwai method or constant) from observed values. All data conformed well to either normal distribution or log normal distribution types. Although one third of all points were satisfactory to the normal distribution, log normal distribution was assumed to be the most acceptable one because of their largest average correlation coefficient with smallest standard deviation. In comparing Japan Environment Agency method and other methods, it was indicated that the differences between 75% probabilities of BOD estimated by Japan Environmental Agency method and those by statistical analysis were not insignificant.

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The concentration of the trace elements in river water, drainage, sediment, periphyton and the larvae of an aquatic insect, caddisfly, Stenopsyche marmorata, which were sampled four times in a year from the water area of the upstream and midstream parts of Tama River, where the drainage from factories flows in, were measured.
The concentrations of nickel, copper, lead and zinc in river water were highest at the downstream of the place where the drainage from factories flows in, and showed the tendency of rapid decrease toward downstream. The concentrations of these elements in sediment were high only at the place where the drainage from factories flows in. The concentrations of these elements in periphyton and the larvae were highest at the downstream of the place where drainage flows in anytime, and gradually decreased toward downstream.
These results suggested that periphyton and the larvae are useful monitors of the contamina-tion with the trace elements in low concentrations for rivers in water areas for city water source, and those make the detection of the contamination with cannot be detected with river water and sediment possible.

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