Identification of α-BHC, TCTP, oxadiazon, CNP and chlomethoxynil by GC-MS and GC-ECD, and survey on level concentration in raw and finished water were previously reported.
We have since then examined the unknown peaks under GC-ECD, and consequently identified organophosphorus insecticides (diazinon, MEP), organochlorine herbicide (benthiocarb), organophosphate triesters (TBP, CRP, TPP, TBXP) and phthalic acid esters (DBP, DHP, DOP). Analysis of multicomponents identified in the previous and present studies has been established except for phthalic acid esters and TBXP.
Oxadiazon, CNP, chlomethoxynil and benthiocarb were detected at the level of ppt during the months these substances were used from a river (raw water) which ran through a paddy region. Diazinon and MEP were detected at the level of ppt also during such months from a river which ran through a cultivated field. TBP, CRP and TPP were detected at almost the same level of ppt throughout the year from the rivers under the influence of environment and industry.
The concentration of oxadiazon, CNP, chlomethoxynil, TBP, CRP, TPP, α-BHC and TCTP in raw water almost agreed with the concentration of them in finished water. However, diazinon, MEP and benthiocarb couldn't be detected from finished water. This fact is attributed to chlorination in water purification plants.

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The phosphorus budget model to predict phosphorus concentration in lake water was improved in order to be applied to a plug flow system. The model for a plug flow system was examined and applied to Lake Inbanuma, a shallow eutrophic lake in Japan. The retention coefficient (R) and the phosphorus concentration in lake water discharging from the lake (P_lout) were expressed for a plug flow system by the following equations : R = υ/ q_s, P _out = L (1- R) /q_s, where υ is the apparent settling velocity of total phosphorus, q_s is the areal water loading and L is the phosphorus loading per unit lake area.
The phosphorus concentrations in Lake Inbanuma were calculated by use of the improved phosphorus budget model. The predicted values and the observed values were in good agreement in the case of the data from 1979 to 1984 of which changes with time were smoothed by means of the moving average method.

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Secondary effluent of domestic wastewater was irrigated using sprinkler at sloping area in forest land, and changes in water quality during a penetration through soil layers in aerobic conditions or estimation on removed portion for each species was determined. The chemical composition of descending effluent was found to vary with modes of spraying. The concentrations of most cations, PO₄^3- and reducing substances (determined as COD) were decreasing, while those of Ca²⁺, SiO_2< and NO₃^- were increasing. An unfavorable influence of land application of secondary effluent on groundwater quality should be monitored by measuring continuously the concentrations of the species of the latter group in draining water. The removed portion for any species was defined as : (Total amount of the species contained in effluent-Total amount of the species remaining in drained water) /Total amount of the species contained in effluent. The calculation showed that the average removed portion (%) for some cations ranges from 94.3% (highest) for K⁺ to 56.7% (lowest) for Na⁺. The average values for Cl^- and SO₄^2- were 46.9% and 35.4%, respectively, demonstrating that the removal of anions during the penetration, therefore, is not effective. The removed portion as defined is a function of water recovery, or the volume ratio of drained water to effluent. The plot of removed portion against water recovery gave a linear relationship, and the slope of the linear equation is related to the retention of the species studied by soils. The retention was found to decrease in the order of K⁺, Fe³⁺, Mg²⁺ and Na⁺.

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he slope of phosphorus concentration against discharge of river reversed at the flux of 105, 000m³/day in Kurose River. On the contrary, such a tendency was not found in Minaga River. Under discharge of river of 105, 000m³/day the slope of DIP against the discharge was negative. In the cold season (October to April), its negative slope increased, while it decreased in the hot season (May to September).
On the other hand, the correlation coefficient of POP with discharge of river was high in the cold season, while it remarkedly decreased in the hot season. As a reason, it is considered that the mechanisms of sedimentation, formation of particles and so on are complicatedly entangled in the river.
Upon discharge of river of 105, 000m³/day which corresponds to the rainy season, POP and its slope against discharge of river were high in comparison with DIP and DOP, suggesting the important role of particle for the phosphorus transport. POP increased with an increase in discharge of river during the rainy season. However, the content of phosphorus in particle was highest at the first flush of rain and rather than decreased with discharge of river.

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[in Japanese]

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