Protesters have gathered in the capital of South Korea to demand that the government take steps to avoid what they fear is a looming disaster from Japan's release of treated radioactive water from the Fukushima nuclear power plant.
About 50,000 people joined the protest on Saturday, according to the organisers.
"We will not be immediately seeing disasters like detecting radioactive materials in seafood but it seems inevitable that this discharge would pose a risk to the local fishing industry and the government needs to come up with solutions," said Choi Kyoungsook of Korea Radiation Watch group that organised the rally.
South Korea has said it sees no scientific problems with the water release but environmental activists argue that all possible impacts have not been studied.
"Nobody can tell what's going to happen to the marine ecosystem in the next 100 years," said Choi.
Division in South Korean politics
Exposing a deep division in South Korean politics, the opposition camp on Friday slammed Japan over its controversial release of treated nuclear waste, dubbing it “environmental terrorism.”
However, the administration of President Yoon Suk-yeol has said it did not find any “abnormalities” as Tokyo’s release of contaminated water from the crippled Fukushima nuclear power plant was “carried out stably and as planned,” Seoul-based Yonhap News reported.
“Japan has ultimately chosen the path of an environmental war criminal,” opposition Democratic Party (DP) leader Lee Jae-myung told a party meeting.
Accusing Yoon as “an accomplice” in Japan’s decision, the South Korean opposition leader said: "I cannot believe the fact that the president has not said a single word regarding the water discharge issue.”
Urging Yoon to “end the silence”, Lee said the South Korean government should “seek compensation from Tokyo.”
Japan keeps dumping
Japan began dumping the water from the plant north of Tokyo into the sea on Thursday despite objections both at home and abroad from fishing communities and others worried about the environmental impact.
Japan and scientific organisations say the water, distilled after being contaminated by contact with fuel rods when the reactor was destroyed in a 2011 earthquake and tsunami, is safe.
Japan says it needs to start releasing the water as storage tanks holding about 1.3 million metric tons of it - enough to fill 500 Olympic-sized swimming pools - are full.
The first discharge of 7,800 cubic metres - equivalent to about three Olympic pools - will take place over about 17 days.
