The nature of the area seems to have not only survived, but flourished due to significant reduction of human impact. The zone has become a "Radiological Reserve", a classic example of an involuntary park. Currently, there is concern about contamination of the soil with strontium-90 and caesium-137, which have half-lives of about 30 years. The highest levels of caesium-137 are found in the surface layers of the soil where they are absorbed by plants, and insects living there today. Some scientists fear that radioactivity will affect the land for the next several generations.