Abstract
In Kuriyama Town, Hokkaido, slags that contained a high concentration of hexavalent chromium(Cr(VI))from a chromium factory was disposed in landfills, both inside and outside the town. Because leachate from landfills was caused environmental problems, we have carried out water quality surveys twice at the rivers and wastewater pipes of Kuriyama Town in 1971. It was found that although many sites had no concentration or relatively low concentration of Cr(VI), the rest of the sites had a high concentration of Cr(VI). The Cr(VI) concentration was lowered because the large-scale landfills were covered with a reducing substance, asphalt, and the small-scale landfills, which were used by households, was managed according to sewage guidelines. The ratio of Cr(VI) found in total Cr varied at different locations depending on whether a reducing substance was present or not. In most cases, Cr(VI) in the rivers was not detected when irrigation water flowed into the river. The Cr(VI) volume discharged from the Tagami landfill was calculated to be approximately 82ton and 27% of content Cr(VI). If other landfills were included, it was estimated that water-discharged Cr(VI) could be more than 100t.
