Influence of Industrial Mass Loads on Total Phosphorus Concentration in River Water

： Effects of the Fifth Regulation of Total Maximum Daily Loading

Abstract

Characteristics of total phosphorus (TP) concentrations in the Kinokawa River were clarified by using existing monitoring data. Numerical analysis to examine mass loads and river water quality were also conducted. The monitoring data showed that the TP concentrations increased markedly in the middle river reaches from 1996 to 2001. The numerical analysis also demonstrated large increases in industrial TP loads from 1996 to 1999, as well as decreases in TP due to reductions in industrial shipments and the promulgation of the fifth regulation of total maximum daily loading. The findings suggested that industrial TP loads and the river flow rate both affected TP concentrations in the river.