Traces of radioactive materials have been discovered across South Korea due to the inflow of contaminants from Japan's stricken nuclear power station, a state nuclear safety body said Saturday.

The Korea Institute of Nuclear Safety confirmed diminishing traces of iodine-131, cesium-137 and cesium-134 have been detected by the country's 12 detection centers.

It, however, stressed that concentration levels posed no real health threats to humans and would not impact the environment.

The latest announcement was based on air samples taken from the 12 detection sites across the nation from 10 a.m. Thursday through 10 a.m. Friday.

The highest concentrations of iodine-131, which was discovered at all detection centers, reached 0.458 millibecquerels (mBq) per cubic meter, with numbers for cesium-137 and cesium-134 reaching 0.130 mBq and 0.118 mBq each. Cesium-137 was discovered in six sites with nine sites picking up cesium-134.

The highest cesium readings were all taken from samples collected from the port city of Gunsan, 274 kilometers southwest of Seoul, with top iodine numbers coming from Gangneung on the east coast.

The KINS added that rain samples taken on Friday in Seoul and Chuncheon, 85 kilometers from the capital city, showed no traces of radioactive particles.

Seoul first confirmed the existence of radioactive particles in the air from March 28, more than two weeks after the Fukushima nuclear power plant released radioactive particles into the environment. All concentration levels detected so far in South Korea have been determined negligible. (Yonhap News)