<；P>；PROBLEM TO BE SOLVED: To provide a water area environment improving material for improving a bottom material much in the content of organic matter of a closed water area and the water quality in its periphery, and a water area environment improving method. <；P>；SOLUTION: The water area environment improving material containing diatom bonded slag obtained by bonding a diatom to steel making slag, is sprinkled over the water area having the bottom material much in the content of organic matter. The propagation and photosynthetic activity of benthic fine algae are raised by inorganic nutrients eluted from the steel making slag, and the bottom material and water quality are improved by oxygen discharged from the benthic fine algae. <；P>；COPYRIGHT: (C)2006,JPO&NCIPI
