Scheme for riverine input of toxic trace elements at different flow stages in a rainfall event

Matsunaga, Takeshi; Yanase, Nobuyuki; Kritsananuwat, R.*; Tsuzuki, Katsunori  ; Hanzawa, Yukiko  ; Naganawa, Hirochika  

The input of toxic trace elements to river water in a rainfall event was studied in a forested watershed in Japan. The riverine input of particulate trace elements varied with their different enrichment in suspended particles at low and high flow stages. This input was suspected to cause an increase in the levels of their dissolved components earlier in the rainfall and at a high flow stage. We also found that dissolved organic carbon from a soillayer can carry rare earth elements to a stream at a latter stage of high flow rate.