REPORT COPYRIGHT VIOLATION IN REPLY
|
Message Subject
|
*** Fukushima *** and other nuclear-----updates and links
|
Poster Handle
|
Anonymous Coward |
Post Content
|
The total amounts of radioactively contaminated materials in forests in Fukushima, Japan There has been leakage of radioactive materials from the Fukushima Daiichi Nuclear Power Plant. A heavily contaminated area (≥ 134, 137Cs 1000 kBq m−2) has been identified in the area northwest of the plant.
The majority of the land in the contaminated area is forest. Here we report the amounts of biomass, litter (small organic matter on the surface of the soil), coarse woody litter, and soil in the contaminated forest area.
The estimated overall volume and weight were 33 Mm3 (branches, leaves, litter, and coarse woody litter are not included) and 21 Tg (dry matter), respectively.
Our results suggest that removing litter is an efficient method of decontamination. However, litter is being continuously decomposed, and contaminated leaves will continue to fall on the soil surface for several years; hence, the litter should be removed promptly but continuously before more radioactive elements are transferred into the soil.
A massive earthquake occurred in eastern Japan on March 11, 2011, and a very large earthquake-induced tsunami washed over the Fukushima Daiichi Nuclear Power Plant. The damage to the cooling system of the power plant resulted in several explosions. Radioactive materials leaked as a result of the explosions and the ventilation intended to avoid further explosions.
Radioactive contamination has been widely but inhomogeneously found in eastern Japan, even in areas hundreds of kilometres away from the plant1, 2, 3, 4. Airborne surveys revealed that the contamination spread widely, but areas northwest of the plant, from the immediate vicinity of the plant to approximately 60 km away, were found to be notably heavily contaminated (e.g. ≥ 134, 137Cs 1000 kBq m−2)1, 2.
The two major radioactive elements found to be widely deposited are iodine (131I) and cesium (primarily 134Cs and 137Cs). Because the half-lives of 131I, 134Cs, and 137Cs are 8 days, 2 years, and 30 years, respectively, the decontamination of cesium (especially 137Cs) is now the crucial issue.
The majority of the land in the contaminated area is forest. Forest ecosystems consist of tree biomass (aboveground: boles, branches, and leaves; belowground: roots), small dead organic matter on the soil surface (termed litter), dead trees on the soil surface (termed coarse woody litter), and soil.
Litter includes fallen dead leaves and branches and their decomposed materials. Usually, several centimetres of litter cover the surface of the soil, whereas coarse woody litter is very sporadically distributed on the surface. Two independent, preliminary surveys conducted by the Forestry and Forest Products Research Institute and Forestry Agency of Japan (FFPRI and FAJ) and by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) revealed that radioactive materials primarily remain in the aboveground tree biomass, litter, and shallow soil (0–0.05 m) in forests5, 6. Removing the contaminated components is a potential method of decontamination for forest ecosystems7, 8, 9.
Although the amounts of contaminated forest components are unknown, this information is essential to reveal the extent of the contamination by this tragic, historic nuclear accident and guide decontamination efforts. Here we have estimated the volume and weight of contaminated forest components in the contaminated forest area by combining forest statistics, databases of the distributions of vegetation and soil types, and compilations of data from Japan's forests.Much more Data, Infos and Graphics: [ link to www.nature.com]
|
|
Please verify you're human:
|
|
Reason for copyright violation:
|