びわ湖流入河川の水質の季節変動と粘土鉱物生産量の推定

Abstract

Several observations have been carried out from Oct. 1972 to Sept. 1973 in order to study theseasonal variation of chemical compositions in the eighteen rivers which flow into Lake Biwa andestimate the amounts of clay minerals produced by weathering processes through the chemicalcompositions in natural waters of them.The results are as follows: The concentration of bicarbonate ions among dissolved chemicalspecies shows a largest seasonal variation, the total transported amount of dissolved chemical speciesis estimated as 120 tons/year-k㎡ and the amounts of kaolinite and montmorillonite produced byCO2 bearing water reacting with parent rocks are estimated as 20 tons/year-k㎡ and 1.2 tons/year-k㎡, respectively.It seems that seasonal variation of chemical species in rivers is controlled mainly by dischargevariation.