A few observations:

Chernobyl was a stupid and entirely avoidable incident.  The reactor was not located in a containment building.  That's the reason cesium and radio-iodine got dispersed.  The Three Mile Island reactor that had a partial meltdown had a containment building, so no cesium escaped.  

Twenty years later the death toll stands at 60, with 51 of the victims having died either because of the steam explosion or because of being exposed to extremely high levels of radiation while working to mitigate the accident.  The remaining 9 have died of thyroid cancer from radio-iodine.  If they had received potassium iodide promptly their thyroids never would have taken up the I-131.  If they had received good medical care they would not have died of thyroid cancer, which is a highly treatable malignancy.

The background radiation of the Chernobyl area is naturally low due to an absence of uranium in the soil.  The accident brought the radiation level in the Exclusion Zone to that of parts of Spain and France.  If you were evacuated from the contaminated Exclusion Zone and moved to Finland or the Colorado Plateau you would have increased your exposure to radiation.

Villagers around Chernobyl continued living in mildly contaminated areas.  The rate of death and disease for them is as it was prior to the accident.  For 40 years cancer rates have been steadily rising in E. Europe and are continuing to rise at the same rate.

The biggest public health problem for Chernobyl is the same as the one for Katrina:  diseases and disorders associated with post traumatic stress syndrome in populations that have been suddenly uprooted and have had to live with meager health care and poor nutrition.  Smoking, alcohol and drug abuse, spousal and child abuse are all up.  As with Katrina, this aftermath was preventable.  

Humans evolved in Africa, which has areas that are naturally high in radiation.  Some of the richest uranium is found in Africa. In fact, natural reactors occurred there 1.8 billion years ago. The body knows how to cope with higher levels of radiation than we receive today.  Low-level radiation stimulates the DNA repair mechanisms.