TOKYO, March 11 (Xinhua) -- Radioactive substances in nuclear-contaminated water should not be released into the environment and Japan's discharge plan is inappropriate, a Japanese environmental economist said.
Unlike ordinary hazardous chemicals, radioactive substances do not disappear without chemical treatment as nature's self-purification does not work on it, Kenichi Oshima, a professor at Ryukoku University, told Xinhua in an interview.
Regarding the Advanced Liquid Processing System (ALPS) proposed by the Tokyo Electric Power Company (TEPCO), the scholar questioned its effectiveness, as many researchers believe that the system can not remove nuclides from the contaminated water.
Citing malfunctions in the multi-nuclide removal system of ALPS, Oshima said nuclides other than tritium have not been removed in about two-thirds of the total 1.3 million tons of the nuclear wastewater from the Fukushima Daiichi nuclear power plant.
"TEPCO insists that it will and can handle the issue, but the credibility of such statements needs further observation given there was no precedent," he noted.
Oshima stressed the worrying fact that whether the treated one-third of nuclear wastewater meets standard also lacks review by a third-party organization.
TEPCO has only selected a small number of more than 1,000 nuclear wastewater storage tanks for testing, and all the tests were done by the company itself without third-party verification, he said, citing an article in the Jan. 27 issue of Science magazine this year which criticized TEPCO for releasing not enough data.
TEPCO has acknowledged that even if the ALPS could achieve its expected results, there would still be traces of radioactive substances other than tritium in the treated water, said Oshima, adding that this was also pointed out by the chairman of Japan's Nuclear Regulation Authority.
The scholar stated that it is an "indisputable fact" that these radioactive substances would not have been produced if not for the nuclear accident. "I don't think it is appropriate to discharge these additional radioactive substances, and I understand the widespread opposition to such a plan," he said.
He believed the proper and uncostly treatment is to continue storing treated nuclear wastewater in tanks, and wait for tritium, with a half-life of 12.3 years, to decay to less than one-thousandth of its current level in more than 120 years. Another method is to seal it underground upon mortar solidification and wait for more than 100 years, at which point further treatment methods can be considered.
Since TEPCO holds responsibility for the accident in the first place, it is not in a position to choose how to dispose the water based on cost calculations, but rather has an obligation to minimize the impact on the environment and people, Oshima noted.
The environmental economist also stressed that the possible approval of the International Atomic Energy Agency (IAEA) does not justify Japan's discharge plan as the agency is assessing the plan proposed by TEPCO rather than its long-term impact on the marine ecosystem.
Noting that "the ocean is borderless," Oshima said "there is no corresponding assessment of the long-term impact of radioactive materials on the marine ecosystem and our lives."
"Therefore I don't think IAEA's approval means there is no problem," he noted. ■