Abstract
In a tributary watershed of the Kuji River of Japan, the hydrological components of runoff associated with a precipitation event were investigated using isotope tracers of hydrogen (2H) and oxygen (18O) in precipitations and stream water. The runoff was separated into “old water” (pre-existing in the ground before the precipitation event) and “new water”(from the precipitation). It was found that the discharge of several hazardous trace elements (Sb, Cu, Cr) was largely (24-54%) attributable to that of the new water in spite of its small contribution to the total water discharge. These investigations suggest that the new water may play an important role in the migration of atmospherically derived, hazardous trace elements to streams during precipitation events. The present findings will contribute to current necessity of assessment of a risk of long-term exposure to pollutants at low concentrations by providing information on their transport among different environmental media.
