title: Radioactive cesium in dirt accumulations on the roof of buildings.
abstract: The concentrations of 137Cs and 134Cs in dirt deposits on the roofs of buildings are much higher than those in the surface of soil at ground level. Thus dirt on roofs concentrates radioactive cesium in fall-outs. The 137Cs concentration in dirt deposits on the roofs of older buildings is not consistently higher than that on the roofs of new ones, but the 137Cs/134Cs ratio is higher in deposits on older buildings constructed before the first half of the 1970s, and decreases exponentially with decrease in age of the buildings gradually reaching 1.9 +/- 0.2, the value in the air-borne dust at the time of the Chernobyl accident. From this relationship, the contribution of Chernobyl radioactivity to accumulated 137Cs was calculated as 32% on buildings constructed in 1962. The radioactive cesium concentrations in dirt deposits in gutters of private houses and on the roofs of university buildings in Japan were also determined.
authors.affiliation: Department of Hygiene, School of Medicine, University of Tokushima, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Fujita
authors.forename: H
authors.initials: H
authors.lastname: Mikasa
authors.forename: N
authors.initials: N
authors.lastname: Fujii
authors.forename: Y
authors.initials: Y
authors.lastname: Suzuki
authors.forename: K
authors.initials: K
authors.lastname: Nishiyama
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D002588:Cesium Radioisotopes / Q000032:analysis*; D006798:Housing; D007564:Japan; D013997:Time Factors
chemical_list: D000393:Air Pollutants; D002588:Cesium Radioisotopes