Two rivers of different landuse-type were observed weekly to evaluate the amounts and changes of annual pollution loadings. The observation was made for the first two years and last one year during a 1978-88 period. The observed river discharges were not affected by the annual precipitation but by the influencing rainfall for ten days preceding the observation. The loadings of almost all water quality items usually increased with increasing the annual river discharges, except that those of PO₄-P and T-P decreased by the use of synthetic detergents without phosphorus. The loading of an urban river decreased by the laying of sewer system which cut a part of gray water loading. The loadings of NO₃-N and T-N showed a tendency to increase by the increments of rainwater loading, waste of imported foodstuffs, accumulation of land-applied fertilizer and so on. The ratios of NO₃-N to T-N increased as a secular change, but those of NH₄-N and Org-N decreased. To know the amounts of natural and artificial pollution loadings from three watersheds of different landuse-type (mountainous, agricultural and urban areas), those specific pollution loadings were compared each other and with rainwater loading as a common base loading of the watersheds.

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Distribution of linear alkylbenzenesulfonates (LAS) between the dissolved and adsorbed phase was examined as one of the most important processes in the fate model of LAS in aquatic systems.
Adsorption experiments using solid and sediment taken from a river and lake were performed between 0.39 ppm of the initial solution concentrations of LAS. Coefficient k in the Freundlich isotherm equation (Q=kc^1/n) varied by nearly 1 order of magnitude. This was due to the fact that not only alkyl chain length and phenyl position, but also the fractional organic carbon content of the suspended solids, the concentration of the suspended solids, and the fraction of each LAS isomer were varied.
The experimental equation used to estimate the Freundlich coefficient k of each LAS homologue (C₁₂C₁₄) and isomer (2φ, 3φ, 4φ, 57φ) was verified by using adsorption data from field observations. Values of the observed k in the river and lake were obtained by the field observations using the Freundlich isotherm equation (n=1.75). Freundlich coefficient k of LAS in natural aquatic systems was estimated reasonably (correlation coefficient was between 0.63 0.87).

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[in Japanese]

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[in Japanese]

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[in Japanese]

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