琵琶湖および瀬田川表層水中の溶存反応性アルミニウム濃度とpHの季節変化琵琶湖および瀬田川表層水中の溶存反応性アルミニウム濃度とpHの季節変化AA12714371 Seasonal variation of pH and dissolved reactive aluminum concentration in the surface water of Lake Biwa and Seta River water
Relationship between the pH and the dissolved reactive Al concentration in the surface water of Lake Biwa and Seta River was examined and compared with the results of other laboratory. In the surface water of them, the dissolved Al concentration was reported to show the clear seasonal variation, i.e., high in summer and low in winter. In the North Part of Lake Biwa, the pH began to increase from April (or May) and about one month later, the dissolved Al concentration was reported to begin to increase. On the contrary, we reported that, in the Seta River, the increase of pH and dissolved Al concentration occurred in parallel.We reexamined the data of Seta River and found that the increase in pH occurred sometimes beforethe increase in dissolved Al concentration. The degree of the difference was changed from year to year.In 2014 (from April 2014 to January 2015), the pH began to increase about one week before the increaseof dissolved Al concentration in Seta River water. In the North Part of Lake Biwa, it was failed todetermine the time lapse correctly, although it was confirmed that the pH increase occurred before theincrease of dissolved Al concentration. It was also discussed how to determine the correct pH in lake orriver water.