Evaluation de la qualité de vie et du handicap fonctionnel au cours de la polyarthrite rhumatoïde Étude transversale de 80 cas dans la région de Marrakech

Abstract

The first and second environmental releases of man-made 239 + 240Pu came from nuclear explosions at Alamagordo and Nagasaki in 1945. The release at Nagasaki was more serious than at Alamagordo, because it happened in an area with a high population density. Unfissioned 239 + 240Pu and various fission products (e.g. 90Sr and 137Cs) have been interacting here with various environmental materials (soils, sediments, and plants) under wet and temperate conditions for more than 45 years. To assess the environmental mobility of 239 + 240Pu, the distributions of radionuclides from this release were investigated at Nishiyama (3 km east of the hypocenter) where heavy black rain containing unfissioned plutonium and fission products fell 30 minutes after the nuclear explosion. The vertical distributions of 90Sr, 137Cs and 239 + 240Pu were determined in unsaturated soil cores up to 450 cm deep. Most radionuclides were found in the soil column 30 cm from the ground surface (95% of 90Sr, 99% of 137Cs and 97% of 239 + 240Pu). However, 90Sr and 239 + 240Pu were detected in the groundwater as well below a depth of 200 cm. No 137Cs was found below 40 cm from the ground surface or in groundwater. These observations reveal that about 3% of the total 239 + 240Pu has been migrating in the soil at a faster rate than the remaining 239 + 240Pu. Sharp peak of 137Cs and 239 + 240Pu, indicating heavy deposition from the Nagasaki local fallout of 1945, were found in sediment cores collected from the Nishiyama reservoir. On the other hand, since 90Sr is mobile in fresh water sediments, there was no 1945 90Sr peak in the sediment cores. 239 + 240Pu peaks were unexpectedly discovered in pre-1945 sediment core sections. Although 90Sr was found in these sections, no 137Cs was found. By contrast to the distribution in sediment cores, 137Cs in tree rings had spread by diffusion from the bark to the center of the tree without holding a fallout deposition record. Most of the 239 + 240Pu was distributed in the tree rings following a similar deposition record to that found in sediment cores. Furthermore, a very small amount of 239 + 240Pu (about 1%) was found unexpectedly in pre-1945 tree rings. The only reasonable explanation for these unexpected discoveries is the existence of mobile 239 + 240Pu in the environment.