title: Description of spatial patterns of radionuclide deposition by lognormal distribution and hot spots.
abstract: Spatial distributions of activity density (kBq/m(2)) and activity concentration (Bq/kg) are studied on sites with non-cultivated soils. Fitting datasets with lognormal, Weibull and normal distributions with sampling size n ≥ 60 showed that radionuclide deposition ((90)Sr, (137)Cs, (238)Pu, (239+240)Pu, (241)Am) due to Chernobyl fallout no more than in 10% of cases are described by Weibull distribution, and in the rest of the cases--by lognormal distribution. However asymptotics of "righthand tail" of empirical (sample) distribution quite often differs from the right-hand tail asymptotics of lognormal distribution. Thereby lognormal distribution is only an approximate statistical model of radionuclides' spatial pattern. Estimates of site surface area with "hot spots" are considered. Also distributions of (137)Cs and (134)Cs activity concentration on the territory contaminated by Fukushima fallout are reviewed. Characteristics of activity concentration for Fukushima and Chernobyl fallouts are collated. The results obtained make it possible to suggest that in both cases spatial contaminations of soil are described by approximately the same statistical models.
authors.affiliation: CJSC TIMET, 220015 Minsk, Belarus. Electronic address: timet@inbox.ru.
authors.forename: Andry
authors.initials: A
authors.lastname: Grubich
authors.forename: V I
authors.initials: VI
authors.lastname: Makarevich
authors.forename: O M
authors.initials: OM
authors.lastname: Zhukova
mesh_terms: D000576:Americium / Q000032:analysis; D002588:Cesium Radioisotopes / Q000032:analysis; D011005:Plutonium / Q000032:analysis; D011868:Radioisotopes / Q000032:analysis*; D012990:Soil Pollutants, Radioactive / Q000032:analysis*; D013326:Strontium Radioisotopes / Q000032:analysis
chemical_list: D002588:Cesium Radioisotopes; D011868:Radioisotopes; D012990:Soil Pollutants, Radioactive; D013326:Strontium Radioisotopes; D011005:Plutonium; D000576:Americium
keywords: (90)Sr, (134)Cs, (137)Cs, (238)Pu, (239+240)Pu, (241)Am; Chernobyl fallout; Fukushima fallout; Hot spots; Lognormal distribution