The spatial pattern of global fallout is expected to follow latitudinal bands, in areas characterised by similar levels of precipitation 1. caesium-137 ( 137Cs T 1/2 = 30 years) and most plutonium isotopes including plutonium-239 ( 239Pu T 1/2 = 24,100 years) and plutonium-240 ( 240Pu T 1/2 = 6,560 years) are strongly particle-bound, and thus remain concentrated in the uppermost surface layer of the soil. The main long-lasting radionuclides of radioecological concern emitted during these tests, i.e. After their emission in the stratosphere, they were mainly brought to the soils as a result of dry and wet fallout (i.e., rainfall and snowfall). Understanding the magnitude of these fallout sources is crucial not only to establish a baseline in case of future radionuclide fallout but also to define a baseline for geomorphological reconstructions of soil redistribution due to soil erosion processes.Īrtificial fallout radionuclides (FRN) have been released into the environment during the atmospheric nuclear weapon tests that took place from the mid-1950s to 1980.

Spatial prediction models allowed for a first assessment of the global versus Chernobyl fallout pattern across national boundaries. Accordingly, we used plutonium to quantify contributions of global versus Chernobyl fallout to 137Cs found in European soils. We show that both fallout sources left a specific radionuclide imprint in European soils. Fallout radionuclides ( 137Cs, 239Pu, 240Pu) were measured in soil samples (n = 160) collected at flat, undisturbed grasslands in Western Europe in the framework of a harmonised European soil survey. However, to date, the spatial patterns of these fallout sources remain poorly constrained. Global nuclear weapon testing and the Chernobyl accident have released large amounts of radionuclides into the environment.

Fallout west coast map