Characteristics of the rivers in Toyo River basin [Japan] shown by nitrogen and phosphorus
1983
Sano, M. (Aichi-ken. Environmental Research Center, Nagoya (Japan)) | Tsuruta, T. | Yamanouchi, T. | Sakabe, T. | Ito, M.
Nitrogen and phosphorus compounds in the river waters in Toyo river basin were measured yearly to study the character of the rivers. No seasonal changes of nitrogen and phosphorus compounds were shown in the upper reaches of Toyo river, whereas in the rivers around Toyo river, seasonal changes of them were clear. The proportions of inorganic constituents of nitrogen and phosphorus in total nitrogen and phosphorus were smaller in Toyo river than in the surrounding rivers. These two differences will mainly be due to the various sources flowing in the rivers. From the relations with components studied, it was shown that not only rain, ground water and agricultural, domestic animal's, domestic and industrial wastes, but also attached substance on the river bed will influence the water quality of the rivers. The inflowing proportion of them will decide the character of the rivers. The fluxes of the components were as much in the surrounding rivers as in Toyo river. The N/P value in the surrounding rivers were close to that of marine plankton. These findings suggest that the surrounding rivers will play an important role for the ecological system of Mikawa bay.
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