After struggling through the COVID-19 pandemic, Lee’s livelihood is in the firing line yet again following Japan’s decision to release treated water from the crippled Fukushima nuclear power plant.

Despite the scientific consensus that Japan’s plan does not pose a risk to the public, many South Koreans are not convinced that seafood and fish are safe.

In a recent survey by Consumers Korea, 92.4 percent of respondents said they would reduce their consumption of seafood after the release.

“Of course I’m concerned,” Lee told Al Jazeera.

“It’s not just about my business; it’s about the entire seafood industry,” he said.

“Negative perceptions could lead to a decline in seafood consumption across the board. That would hit us all hard. I worry about the ripple effect this issue might have on the entire market.”

On Thursday, the first day of Japan’s discharge of treated water, unease permeated Seoul’s Noryangjin wholesale fish market, South Korea’s largest seafood hub.

Outside the market, banners sought to assuage consumers’ concerns with messages such as “Our seafood is safe! Consume with confidence!” and “False rumours are causing public anxiety; this cannot be tolerated any longer!”

Merchants approached by Al Jazeera were hesitant to engage with the media, with more than a dozen vendors refusing interviews.

One merchant, who asked to remain anonymous, expressed frustration at the media’s portrayal of the situation, which she believed had exacerbated the challenges her business was already facing.

“Positive or negative, it does not matter. All this noise is bad for business. We just want to move past this,” she told Al Jazeera.

At the Fukushima plant, about 1.34 million metric tonnes of treated water used to cool the facility’s reactors is stored in some 1,000 tanks. The removal of water, which is expected to take decades, is a key part of decommissioning the facility, which was crippled by a tsunami in 2011.

The International Atomic Energy Agency (IAEA) has backed the plan, finding it to be “consistent with relevant international safety standards” with a “negligible” effect on people and the environment.

While Japan is removing most of the radioactive material from the discharged water, some tritium, a radioactive isotope of hydrogen, will remain.

To counteract this, the water is being diluted to reduce tritium levels to a minimum of one-seventh of the WHO’s threshold for safe drinking water. According to a live IAEA monitoring website, current tritium levels are 50 times lower than the WHO limit of 10,000 becquerels per litre.

Operational nuclear plants, including those in South Korea, release significantly higher levels of the hydrogen isotope. South Korea’s Kori nuclear plant discharged liquid effluent containing 47.35 trillion becquerels of tritium in 2022, according to official data. Japan has said the Fukushima plant will release up to 22 trillion becquerels per year.

Scientific consensus

Scientists around the world, including in South Korea, have backed Japan’s plan.

South Korea’s own official analysis has found that the plan meets international standards and government officials have in recent days reiterated that they see “no scientific or technical problems” with it.

Nonetheless, the government has warned of legal action if the discharge falls short of acceptable norms and promised to maintain import restrictions on fishery products from eight Japanese prefectures, including Fukushima.

In Seoul, city authorities said they would conduct daily testing on all kinds of seafood sold at the city’s major wholesale markets, regardless of country of origin. Over the weekend, tests on waters surrounding South Korea detected radiation well below WHO standards.

To help support the local seafood industry, the South Korean government is reportedly considering asking catering companies to use more seafood as a way to boost consumption and alleviate customer concerns about safety.

The scientific consensus and precautionary measures have done little to assuage critics of Japan’s moves.

Greenpeace has argued that the radiological risks “have not been fully assessed”. The Korean Federation for Environmental Movements has claimed the discharges will have “detrimental effects on marine ecosystems and humanity”.

Many South Korean consumers are apprehensive, too.

“I find myself second-guessing whether it’s truly safe to consume seafood now,” Kim Jun-hyun, an office worker in Seoul, told Al Jazeera.

“It’s hard to ignore the concerns, even if experts claim it’s safe,” Kang, mother of two who asked to be referred to by her surname, told Al Jazeera. “And I don’t trust what the Japanese government is saying.”

In recent weeks, sea salt hoarding has become common, while local supermarkets have reported a surge in sales of dried seafood products.

The opposition Democratic Party, which has traditionally taken a hard line on South Korea’s former coloniser Japan, has used the issue to attack the conservative administration of President Yoon Suk-yeol.

Party leader Lee Jae-myung, who is embroiled in a number of corruption scandals, last week likened Japan’s move to an “act of terror” and World War II. Over the weekend, thousands of protesters rallied in Seoul accompanied by Lee and senior members of other left-leaning parties.

On social media, former President Moon Jae-in, whose administration had previously said it would accept the IAEA’s recommendations, voiced his opposition to the plan and accused Yoon’s government of “doing the wrong thing”.

Yoon, who has grappled with low approval ratings for most of his presidency, has expended significant political capital on improving ties with Japan in recent months, leaving him vulnerable to the charge of being pro-Japanese.

Jo Yangh-yeon, head of the Center for Japanese Studies at the Korean National Diplomatic Academy, said the opposition is using the Fukushima issue as “ammunition” to criticise the government ahead of parliamentary elections next year.

“Some political forces are opportunistically exploiting the public’s concerns about food safety,” Jo told Al Jazeera

Jo said the politically charged atmosphere in South Korea ensured that the Fukushima issue would revolve around perceptions rather than “facts”, “thereby impeding the government’s efforts to relieve people’s anxiety over food safety, and causing public opinion to be deeply divided”.

“Anti-Japanese sentiment in Korean society is indeed the most expedient tool for opportunistic politicians to garner support,” he said.

Seafood merchants were already grappling with declining sales in the aftermath of the pandemic. At the Busan Cooperative Fish Market, the average price of fish per kg was 1,970 won ($1.49) in July, down 34 percent compared with the same period the previous year.

With safety concerns showing no signs of letting up, the Jeju Research Institute has estimated that losses for the local industry could top 3.72 trillion won ($3.02 bn).

For Lee, the restaurant owner, uncertainties about the future loom large.

“What worries me most is the long-term impact,” he said. “Even if the radiation levels are within safe limits, will customers still be hesitant to order seafood?”