TOKYO - Local residents in Japan on Thursday submitted a joint petition urging the Japanese government to retract its plan to discharge nuclear-contaminated wastewater into the ocean.

The petition, signed by 28,627 people, was handed to representatives of the Ministry of Economy, Trade and Industry jointly by 17 organizations, including the non-governmental organization Friends of the Earth Japan and Citizens' Nuclear Information Center.

The petition campaign commenced in May 2020, collecting signatures through online platforms and mails.

The signatories are demanding that the Japanese government reconsider its plan of releasing radioactive water from the crippled Fukushima Daiichi nuclear power plant into the sea, and instead continue with on-land storage or explore alternative solutions.

Hit by a magnitude-9.0 earthquake and an ensuing tsunami on March 11, 2011, the Fukushima Daiichi nuclear power plant suffered core meltdowns that released radiation, resulting in a level-7 nuclear accident, the highest on the International Nuclear and Radiological Event Scale.

The plant has been generating a massive amount of water tainted with radioactive substances from cooling down the nuclear fuel in the reactor buildings, which are now being stored in about 1,000 storage tanks.

Stored nuclear-contaminated water at the Fukushima Daiichi nuclear plant contains not only tritium but various other radioactive substances, the cumulative quantities of which have not been publicly disclosed, said representatives of the petitioning organizations on Thursday.

They emphasized the concerns raised among domestic and international stakeholders, including those within the fishing industry.

In 2015, the Japanese government and the Tokyo Electric Power Company (TEPCO), the operator of the Fukushima Daiichi nuclear power plant, made an agreement with fisheries cooperative associations of both Fukushima prefecture and the nation that they will not proceed with any wastewater disposal "without the understanding of relevant parties."

However, the Japanese government announced in April 2021 its controversial plan to release diluted wastewater into the Pacific Ocean and stated in January this year that the discharge will start "in the spring or summer."

"Just like we can't casually dispose of any kind of waste in our lives, the waste produced by nuclear power plants, including nuclear-polluted water, should never be released into the ocean. Tokyo Electric Power Company should manage their own waste generated locally," a petitioner who goes by the online name of Kazuki Shibata said.

"Once released, there is no turning back. Talking about dilution with seawater is merely a pseudoscientific argument we've heard all too often," wrote another petitioner using the name Tsutomu Aihara.

Japanese media outlets widely predicted that Prime Minister Fumio Kishida, after returning from his visit to the United States, will convene a cabinet meeting to determine the specific discharge date.

The start of the discharge process is widely believed to occur between the end of this month and early September.