Even low doses of background radiation lead to adverse health effects that can be measured in epidemiological studies. It is therefore misleading to claim that radiation exposure can be considered harmless as long as it falls within the dose range of “natural” background radiation. Even the normal routine operation of nuclear power plants leads to discernible adverse health effects in the surrounding population.

Depending on the distance, higher incidence rates of leukaemia and other forms of cancers in children under five years of age have been found in the vicinity of nuclear power plants.Workers occupationally exposed to ionising radiation show significantly higher rates of cancer than other groups, even when official dose limits are not exceeded. The health of their children is more damaged than that of other children.

As a result of low-dose exposure to radioactive iodine, thyroid disease - including cancer – has been observed in children, adolescents and adults. Furthermore,
low-dose ionising radiation causes severe non-malignant diseases such as meningioma and other benign tumour entities, cardiovascular, cerebrovascular, respiratory, gastrointestinal and endocrinological disease and disorders, psychiatric conditions, as well as cataracts.

Studies have also been able to show that in-utero and childhood exposure of the brain to ionising radiation leads to impaired cognitive development.

Subsequent to nuclear accidents, teratogenic effects have been observed both in animals and humans, even those only exposed to low levels of radiation. Some genetic effects can already be seen in the first generation of descendants, others only begin to appear in following generations. The latter may therefore be difficult to confirm. Numerous studies carried out in the “death zones” of Chernobyl and Fukushima on animals that have a high generational turnover show severe genetic defects that can be associated with the level of radiation exposure in their habitat. In humans, such defects have long been observed following low-dose radiation exposure. Transgenerational, i.e. genetically fixed radiation effects, have been frequently documented, for example in the children of Chernobyl 'liquidators'. Numerous other studies also suggest genetic or epigenetic long-term damage caused by ionising radiation.