After a tsunami disabled the Fukushima Dai-ichi plant in March of 2011, residents of the nearby city of Minamisoma, just 14 miles from the plant, were evacuated.
But within a few months, most returned to their homes. Still, many communities near the plant have remained skeptical and concerned about possible radiation exposure.
To find out how much radiation exposure these people have received, Japanese researchers measured levels of radioactive cesium in nearly 10,000 residents starting six months after the incident.
The researchers' study, published today in the Journal of the American Medical Association, showed that about a third of the residents had detectable levels of radiation.
But only one person appeared to have received a radiation dose higher than the maximum recommended by public health officials (the equivalent of about two mammograms). And levels in children were generally lower than in adults.
Public health researchers are concerned that the bigger public health effects of the Fukushima disaster may be anxiety and trauma among plant workers.
Before the tsunami, workers who wore the blue uniform of the power company TEPCO were held in high esteem. But that changed after damaged reactors released radiation and triggered a massive evacuation.
Another paper in the JAMA finds that discrimination and slurs were a major source of psychological distress for TEPCO employees.
The study of more than 1,700 workers found that hostile treatment after the disaster was a more powerful factor than witnessing an explosion at the plant or even having a near-death experience.
And as NPR's Richard Harris has reported, physicians in Japan don't generally treat mental health issues.