抄録
Bromate ions exist in drinking water are by-products of ozonation of bromide-containing water and are also found in sodium hydrochlorate which is used as a disinfectant. Bromate ions cause the renal cell tumors in rats fed within aqueous bromate. In this paper, we present an overview of bromate ion concentrations in the Tama area of Tokyo, Tama River water, sewage treatment water and drinking water. Several samples of surface water and sewage treatment water were analyzed for bromate ion content from November 2002 to March 2003. Bromate ions were not detectable in the upper part of the mains tream and two tributary streams of the Tama River. However, in the mid-regions of the Tama River, the bromate ion concentration increased to 0.7-1.8 μg·l-1. Sewage treatment water samples from six treatment plants had bromate ion concentrations of approximately 0.1-6.3 μg·l-1, and we calculated that 0.7-1.7 kg of bromate ion flow into the Tama River daily. We also determined the concentrations of bromate ions in 449 drinking water samples provided by the Bureau of Waterworks of Tokyo, other waterworks in the Tama area and water supplies for individual use. Among these samples, bromate ions could not be detected at concentrations greater than 10μg·l-1.
