Seventy US civic groups sent a joint letter to Japan opposing the release of contaminated water from the Fukushima Dai-ichi nuclear plant, arguing that Japan’s filtration system is insufficient to make the water safe.

According to the Korean Federation for Environmental Movement on Tuesday, US nongovernmental organizations including the Manhattan Project for a Nuclear-Free World wrote to Japan’s Ministry of Foreign Affairs and its Ministry of Economy, Trade and Industry on June 5 on the occasion of World Environment Day and World Maritime Day.

In the letter, they strongly condemned the recent decision by the Japanese government to release approximately 1.25 million metric tons of radioactive water from the crippled Fukushima Dai-ichi nuclear power plant into the Pacific Ocean.

“We are very concerned that Hitachi’s Advanced Liquid Processing System (Japan’s multi-nuclide removal system) cannot remove all radioactive materials before the dumping as the Japanese government has repeatedly admitted,” the statement said.

“The contaminated water stored at the Fukushima Daiichi is fundamentally different from the water coming from a nuclear power plant during a regular operation.”

They said the contaminated water at the Fukushima Dai-ichi nuclear plant was highly radioactive because it was used to cool the highly radioactive melted cores of at least four nuclear reactors at the plant, where the loss of their cooling capabilities caused meltdowns in March 2011.

Due to the ongoing high levels of radiation at the facility, the water that has accumulated there has extremely high levels of radioactivity, the statement said.

“We are also concerned about the long-term impacts on the wide Pacific region from the dumping of such a large amount of radioactive water. The Pacific Ocean accounts for a large percentage of the world’s fisheries and many of the communities in the region are dependent on these resources.

“Many of the states in the Pacific have long suffered from the effects of nuclear testing and illicit dumping of radioactive waste by wealthy nations. We must not forget that these communities have still been living with the threats of remaining contamination exposure, decimated environments and generational trauma from nuclear testing.”

They argued that dumping radioactive water into the Pacific would violate international law.

The Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter of 1972 and the London Protocol prohibit the dumping of radioactive materials into the sea, at any concentration, the statement said.

The Manhattan Project for a Nuclear-Free World, which led the efforts to send the joint letter, is a nonprofit organization founded in New York City in March 2012 by experts, lawyers and others concerned about nuclear power and the dangers and humanitarian effects of nuclear weapons.

In April, Japan announced that it would discharge more than 1.25 million metric tons of contaminated water from the nuclear power plant into the Pacific Ocean, arguing that it posed no threat to human health.

Upon hearing the news, South Korean experts warned that high-risk radioactive materials not properly filtered before being discharged into the sea could be hazardous to people in Korea and neighboring China.

According to last year’s data released by the Tokyo Electric Power Company, only 30 percent of the 1.25 million tons of contaminated water treated with its advanced liquid processing system -- which is supposed to clean up radioactive contamination -- passed safety standards.

Radioactive materials such as cesium-137 and strontium-90 were found in the remaining 70 percent. Strontium-90 increases the risk of leukemia and bone cancer, according to a report from the Korea Energy Information Culture Agency, a government-funded think tank. Tritium, another radioactive material, cannot be removed by the process.

The Korean government proposed this month that the two countries form a bilateral consultative body in Japan to discuss the issue of contaminated water at the Fukushima nuclear power plant. If Japan agrees, the body could begin operating as early as next month.

By Shin Ji-hye (shinjh@heraldcorp.com)