A water quality survey was conducted at the Tsuto River. The water transparency was decreasing from upstream to downstream, and the concentrations of chloride ions and organic matter were high in the middle
portion of the stream. This trend was considered to be due to an influx of drainage from household and factories. The concentration of nitrate nitrogen was high in the upstream region, and the concentration of ammonia nitrogen was high in the middle region. It was suggested that the higher concentrations of ammonia nitrogen are due to the feces and urine of many aquatic organisms such as fish and ducks. Organic phosphoric
acid triesters which are used as plasticizers, were detected in water samples from the Tsuto River. The level was lower than the acute toxicity value for fish. Ultraviolet absorbers that were used to prevent the deterioration of plastic were not detected in water samples.
津門川の水質調査
202012_185-04
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