The government says radioactive contaminated water discharged from Japan’s Fukushima Number One nuclear power plant is highly unlikely to pollute South Korean waters via ocean currents.

Korea Institute of Nuclear Safety President Yun Choul-ho told reporters on Wednesday that ocean currents tend to alter less than air currents. He added that it takes three to four years at the fastest for ocean currents to move in a certain route and make one rotation.

Yun said even if radioactive materials enter South Korean waters via the currents, some materials would return to Japan’s waters and thus the amount that ends up entering South Korean waters would be small.

The president also dismissed the possibility that the food chain in the nation’s waters would be contaminated with radioactive substances from Japan due to the migration of fish. He refuted the speculation by saying that the habitats of fish are different depending on the water temperature and the environment.

Yun, however, was quick to add that as a precautionary measure, his institute is analyzing marine organisms and seawater from 20 locations in the East Sea, Yellow Sea and southern coasts for radioactive substances. He said test results regarding radioactive iodine will be announced on Sunday and results on whether any radioactive plutonium were found will be unveiled next Tuesday.