Radioactive substances have been found in rainwater from the nation's southernmost island of Jeju.

The Korea Institute of Nuclear Safety on Thursday said that rainwater taken from Jeju on Wednesday and Thursday contained up to 2.77 becquerels of radioactive iodine per liter and 1.901 becqerels of radioactive cesium per liter.

The institute said that the figures are a mere one twentieth or one 110th of the level respectively that amounts to a human’s yearly allowance to radiation exposure.

The test results of radioactive substances in rainwater from other regions will be announced on Friday.

Meanwhile, radioactive iodine and cesium were found in the air at all 12 monitoring stations nationwide.