The distribution and speciation of antimony in river water, sediment and biota in Yodo River, Japan

Abstract

In 1993, the Japanese government set the guideline concentration of 2 μg 1−1 for antimony in natural water and drinking water as an item for precautionary monitoring in consideration of its chronic toxicity, however in 1999 the guideline value was tentatively canceled to examine the health risk of antimony through the accumulation of more information and data for detailed risk assessment. In this study, the distribution of antimony in the river water environment including water, sediment, aquatic plants and fishes was surveyed in the Yodo River basin. The characteristics of antimony distribution between river water and sediment were determined by the batch sorption experiments, focusing on the difference in oxidation state. This study suggests that biota in the Yodo River basin have antimony at concentrated levels. Some of the sewage treatment plants seemed to influence the concentration of antimony in river water. It was shown that the pentavalent antimony is dominant in river water and especially paramount downstream of the sewage treatment plants, though the trivalent antimony is dominant in industrial use. According to the sorption experiments of antimony on river sediment, the trivalent antimony is sorbed faster and more in partition than the pentavalent antimony.