ORIGINS OF BROMIDE ION IN THE LAKE BIWA-YODO RIVER BASIN

Abstract

  A basin-wide survey on bromide ion concentration was conducted in the Lake Biwa-Yodo River Basin. Bromide ion concentration in the downstram area was approxymately three to four times higher than in the upstream areas of the rivers flowing to Lake Biwa. This result indicated that the contribution of the bromide ion from anthropogeic activities to total bromide ion load was much greater than naturally occuring bromide ion. Also, bromide ion loads from wastewater treatment plants were compared with the land use of corresponding coverage areas, and it was found that significat amount of bromide ion was discharged from commercial and industrial activities rather than domestic activities.