Japan's Fukushima nuclear plant operator is readying to release treated water on Thursday despite opposition.
The Tokyo Electric Power Company (TEPCO) has filled a facility, which is called a discharge vertical shaft, with the treated and diluted water, public broadcaster NHK News reported on Wednesday.
"Each ton of treated water has been mixed with about 1,200 tons of seawater," it added.
International Atomic Energy Agency has said release of the nuclear waste would have "negligible radiological impact on people and the environment" but refused to endorse Tokyo's decision. The watchdog will regularly release information on the discharge of the treated radioactive water.
Tokyo has faced massive criticism over the move from its neighbors, especially China.
"The nuclear-contaminated wastewater released from Japan's Fukushima (nuclear power plant) will reach the coastal waters of China 240 days after dumping, and will reach the coast of North America and cover almost the entire North Pacific Ocean in 1,200 days," Beijing-based daily Global Times reported, citing a research report from Tsinghua University.
South Korea's main opposition Democratic Party Wednesday denounced Tokyo's plans.
"We strongly condemn Japan's contaminated water terror," Seoul-based Yonhap News reported citing Democratic Party lawmaker Lee Jae-myung.
"Japan's release of nuclear-contaminated water will be recorded as the Second Pacific War," he said.
Hong Kong will impose a ban on imports of seafood from at least 10 regions in Japan.
In its first phase, Japan will dilute 7,800 tons of the treated water with seawater and the diluted water will be released over the course of 17 consecutive days.
There are some 1.3 million tons of treated water at the TEPCO complex and the operator is running out of storage capacity which has forced Japan to release the water into the ocean.
In March 2011, a magnitude 9.0 earthquake triggered a tsunami that struck out the backup electric supply at the power plant on Japan's northeastern Pacific coast, leading to meltdowns in three of its reactors.
