Radioactivity in Soils (Cesium-134 and Cesium-137)
The repercussions of the reactor disaster in Chernobyl on 26 April 1986 continue to this day. Over several weeks, radioactive caesium-134 and caesium-137 were released in the wake of the disaster at the nuclear power plant. Through fallout and washout, i.e. descending radioactive dust and rain, these substances ultimately infiltrated the soils, thousands of kilometres away from the site of the accident in Ukraine.
In Germany, Bavaria, southern Thuringia and parts of Baden-Württemberg were particularly strongly affected. The Federal Office for Radiation Protection (BfS) reported even in 2018 that wild growing berries and mushrooms as well as game meat are still contaminated today.
In Berlin, too, radioactive caesium accumulated in the soil. Four maps of the Environmental Atlas illustrate the contamination before and directly after the reactor accident as well as on 1 May 1987 and 1 May 1991. Five years after the disaster, caesium-134 had already been degraded by about 80 percent, while about 90 percent of caesium-137 was still detected in the soil. Because it degrades extremely slowly, forest fruits, mushrooms and animals growing and living on undisturbed, humus-rich forest soils of the city may still display increased levels of radiation.
Another reason why radiation levels were monitored in Berlin even before the Chernobyl reactor accident: in the 1950s and 1960s, the nuclear-weapon states the United States, the Soviet Union, the United Kingdom, France and China carried out atmospheric nuclear weapons tests in various regions of the world. These tests caused varying levels of radiation that had to be monitored.