Radiation contamination by Fukushima accident in Kashiwa campus of University of Tokyo, which is located in the northwestern part of Chiba prefecture, was surveyed and decontamination methods were tested in nursery lawn in the campus. In open space and forests in the campus, air dose rate at 1 m aboveground was 0.3–0.6 μSv/h, and soil radiation was 39–137 kBq/m2 in the campus green. From vertical profiles of the pollution in lawn soils, radioactive cesium was found to be concentrated in the 0–1 cm layer of the surface soil and the amount of cesium in the clay particles (35–107 kBq/m2) was significantly greater than cesium amount in turf leaves, roots and thatch. Decontamination by mowing the turf and vacuuming up the thatch with a reel mower and a rotary mower (A-method) was not effective, while stripping the turf and surface soil layer with a sod cutter (B-method) decreased the air dose satisfactory from 0.4–0.6 μSv/h to 0.11–0.21 μSv/h at 5cm aboveground. Around the drain of roof gutter, soil pollution was higher than 100 kBq/kg at the surface 2 cm layer and more than 10 kBq/kg at 4–6 cm depth, and soil replacement to 6 cm deep reduced the air dose rate at 5 cm aboveground only to 0.5 μSv/h.
The purpose of this research is verification of the heat insulation effect by sheet planting installed in metallic roof. The heat insulation effect of a grass and a Sedum was compared. And water supply and non-supply Sedum was compared. The temperature point was set to surface of each planting, the back side of planting, and surface of metallic roof under planting. The analysis object period was from Aug. 1 to 31 in 2011. The result is as follows. The surface of metallic roof amounted to 54.3ºC at highest during the experimental period. At the time of the highest temperature, the surface of grass was 44ºC and the surface of the Sedum under water supply was 46ºC. Simultaneously, the back side of grass base was 38.9ºC and the back side of Sedum under water supply base of the base was 34.5ºC. The same temperature fall effect was accepted for Sedum under water supply and Sedum under water non-supply after rain 4 days. That is, as for sedum planting, it was accepted that everyday water supply and water supply of 4 day interval have the same temperature fall effect.