Richard Morin, a medical physicist with the American College of Radiation, said the agency's evacuation limits are "intended to be extremely conservative," and that none of the levels found would pose a risk to human health. They all fell well below the radiation contained in a heart scan.
Separately, agency officials said Singapore authorities had measured radiation readings from cabbage imported from Japan that were up to nine times above international recommended safety levels — iodine 131 readings of up to 936 becquerels per kilogram.
Earlier, IAEA head Yukiya Amano told reporters that he had issued invitations to government ministers from the agency's 151 member nations to attend a June conference on safety procedures at nuclear plants worldwide in the wake of the Japan disaster.
Amano said the conference will focus on assessments of the Fukushima Dai-ichi disaster and lessons that need to be learned from it.
Veronika Oleksyn contributed to this report.