Most of the monitoring points involved in the program for the measurment of water quality in coastal areas were arranged within several years after the setting of Environmental Water Quality Standards. The arrangement of these points were designed according to the qualitative guideline as to the water quality survey method released by Enviornmental Agency in 1971. Then the monitoring points should be verified whether the arrangement satifies the objectives of survey such as the compliance with Environmental Water Quality Standards and detection of trends when the sufficient data to analyze the arrangement are accumulated.
The arrangement method for coastal areas, however, have been scarcely reported. The water quality in coastal areas presents a variety and complexity of factors absent in rivers and lakes. These render monitoring points in coastal areas difficult to study.
This paper presents a statisitical method to aggregate the monitoring points in coastal areas. This method is characterized by selection of the parameters for analysis based on the calculation results of the partial lambda statisitics and use of the probability of misdiscrimination as a similarity index to aggregate points, which are obtained from the discriminate analysis. The proposed method was applied to Sagami Bay as a case study and reasonable results were obtained.

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Zn, Cd and Mn bearing ferrites suspensions were obtained by air oxidation of heavy metal and ferrous hydroxide, Fe²⁺/M²⁺ molar ratio in the initial suspensions were 2-32 at initial pH 12 and 60°C. The pH of ferrite suspensions were adjusted to 1-7 and the dissolution of heavy metals from these suspensions was studied. The metal ions corporated into the ferrite are stable at pH 2.5-4.5.
The ferritization of Zn, Cd and Mn ions was estimated by the stability (=1 - the dissolved heavy metal ratio at pH3-3.5.)
The stability in the ferritization linearly increased with aeration time and stopped at completion of Fe²⁺ oxidation, detected by DO concentration of the suspension. The optimum initial pH was near 12 by considering the effects on final pH in the ferritization, heavy metal ions concentration of treated water and the stability.

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Mutagenic activity of leachate from a municipal solid waste landfill was surveyed with reference to clarification treatment by means of the Ames Salmonella assay. Mutagenicity for TA98 without metabolic activation by S9 was observed among 29% of raw leachate samples, whereas the mutagenicity rate was increased up to 72% in effluent water samples from a pre-aeration tank where leachate was received ca. 12 h of preliminary aeration. Further treatment of leachate by contact aeration, coagulation-sedimentation, sand filtration, and chlorination did not alter the mutagenicity rate as a mean. Effluent water from pre-aeration tank, however, did not show any increase in mutagenicity when no aeration took place, suggesting that the increase in mutagenicity in leachate at the pre-aeration tank was due to the aeration of leachate. Further investigation showed that mutagens could be removed during treatment on several occasions. This result indicates a possibility of establishing effective treatment to remove mutagens from landfill leachate.

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In order to investigate appropriate microbiological indicators for organic pollution of river water, water samples were collected from 10 rivers distributed in northeast Kyushu, and the following points were examined : (i) cell number of colony-forming bacteria on nutrient-poor and nutrient-rich agar medium, (ii) cell number of directly-counted bacteria, (iii) a flora of heterotrophic bacteria, (iv) cell number of LAS-assimilable bacteria, (v) biodegradability of LAS, (vi) a range of environmental variables. The results indicated that the ratio of the cell number of bacteria grown on nutrient-poor medium (1/20 PYG medium) to that grown on nutrient-rich medium (PYG medium : polypeptone 5.0g, yeast extract 2.5g, glucose 1.0g and agar 15g in 1,000ml of distilled water) is important as an indicator of organic pollution, as well as both the cell number of colony-forming bacteria and that of directly-counted bacteria. The ratio of bacterial number decreased with increase of BOD in the river water (ratio 3 or more, BOD 0.8-0.9mg·l^-1 ; ratio 2-3, BOD 0.9-2.0mg·l^-1 ; ratio 1-2, BOD 2.0-2.9mg·l^-1).
Biodegradability of LAS were more useful as an indicator of bacterial activity in river water contaminated by some domestic waste water than the cell number of LAS-assimilable bacteria.

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