Straight Talk presenter Eugene Chan (left) interviews Chairman of the Advisory Council on Food and Environmental Hygiene Kenneth Leung on TVB, Sept 12, 2023. (PROVIDED TO CHINA DAILY)

City University Professor, marine ecology expert, and Chairman of the Advisory Council on Food and Environmental Hygiene Kenneth Leung is on Straight Talk this week.

Professor Leung says Japan's decision to discharge contaminated water into the sea will likely have a long-term impact on marine life since it is doing so every minute for the next 30 years. He says Japan should allow third party experts monitoring and taking sample there to restore confidence. He also says the money spent on testing these products is well spent to protect public health and safety in Hong Kong.

Check out the full transcript of TVB’s Straight Talk host Dr Eugene Chan’s interview with Professor Kenneth Leung.

Chan: Good evening and a warm welcome to Straight Talk! Our guest this evening is Professor Kenneth Leung from City University of Hong Kong, where he is chair professor of the Department of Chemistry and serves as director of the State Key Laboratory of Marine Pollution. Professor Leung’s research interests include ecotoxicology, marine pollution, biodiversity conservation, and ecological restoration. He has received several awards, including being on the 2018 list of top 100 Asian scientists, and this year, the gold medal of the Asia International Innovative Award. He is also the chairman of the Advisory Council on Food and Environmental Hygiene for our government. And that is why we have invited him to tell us if it is safe to consume imported Japanese seafood. Welcome, Kenneth!

Leung: Thank you, Eugene!

Chan: Professor, as many of us know that Japan started releasing the treated radioactive water from its damaged Fukushima power plant into the Pacific Ocean about two weeks ago. Since then, the question of food safety has attracted worldwide attention. At present, the Hong Kong SAR government has banned import of aquatic products from 10 prefectures in Japan. And there have been debates whether the safety of eating can be confirmed in Hong Kong. And you being the chairman of the Advisory Council on the Food and Environmental Hygiene, can you tell us what advice did you give the government? And is that the reason why now we have this seafood ban?

Leung: So, in Hong Kong, the food safety measure is based on risk assessment or evidence based. Since the discharge of the nuclear wastewater, it is a new risk factor. That's why we have to enhance our safety measures by banning the aquatic products from the 10 prefectures. At the same time, we will do active monitoring for all imported aquatic products from Japan outside that 10 prefectures. So, these are two measures to safeguard our citizens’ health. I think this kind of measure is really well supported by our members. 

Chan: Right. Professor, having a good scientific background, I think that is what we want to hear, the viewers want to have a sort of background before they make a decision whether they will continue to have Japanese food, whether to feel safe to import the Japanese seafood. So, what are the immediate concerns for the safety of seafood or other marine products, as you just said, following the release of this nuclear wastewater. What will be the effect to the seafood?

Leung: Since the new risk factor is from the discharge of the wastewater into the ocean, then the possible risk to our food products is mainly related to aquatic products. That's why the government aims to, try to minimize this risk, by prohibiting the food from those 10 prefectures. 

Chan: Okay. So, are you saying that there could be a long term effect on this radioactive contamination of the seafood?

Leung: You are correct. Since the discharge is going to be conducted for more than 30 years, talking about releasing this partially treated wastewater every minute for more than 30 years, then the volume is huge, it is equivalent to 500 standard swimming pool size. Even though the low-dose condition, but you multiply the volume, the net amount of radionuclides remain high. 

Chan: Right. Professor, the International Atomic Energy Agency from the United Nation has reported the concentration of tritium, which is the radioactive substance in the nuclear effluent discharge into the ocean by Japan, is lower than expected, and poses no risk to humans, this is what they say. So, is there no need for our public to be concerned? Especially it is such a low dose, although it is for 30 years?

Leung: According to their report, the IAE report, they also measured the treated wastewater in terms of the nuclide inside, they also found … apart from tritium, they also found six other radionuclides, including strontium, caesium, iodine, and also carbon-14 radioactive substance. So, those are the main concerns because they can remain in the environment for long long time. And also they could be accumulated in biota, and then through the food web, eventually there may be biomagnification, end up high concentration in seafood product. If humans consume them, we may have a health hazard. 

Chan: Right. So, you are saying that the IAEA saying that when they poses no risk to humans, you don't agree?

Leung: So this is talking about more for long term, so the IAEA report also mentioned that Japanese government should monitor the concentration in seawater sediment and biota for long term, so that they can ascertain how the pollutants increase in the environment and whether it will trigger the threshold, causing adverse effect. 

Chan: Right. Professor, you know when Japan began discharging their nuclear wastewater on Aug 24, the Hong Kong government immediately banned the import of aquatic products from the 10 Japanese prefectures. Do you think the scope of ban is adequate? Or you think it should extend further than more than 10 prefectures?

Leung: So, as I mentioned, our government used a risk-based approach, that means we will collect information, scientific data, not just from our own government, but also the neighborhood government, different cities. So, if in the coming few years, all these cities with the intelligence telling us that all the seafood products from Japan are safe, then we’re going to have a chance to relax the measures, okay? But on the contrary, if they provide us the data or our own data suggest that the otherwise, then we may tighten the monitoring and also the measures.

Chan: Right. Just now when you saying monitoring, we are basically doing a sampling method in Hong Kong. By sampling meaning they don’t test every single food produce, but takes samples from it. Why can't we go to the water there and test it? Because at the moment, it is all from the Japanese side. Would it be more sensible or more independent, make us more comfortable, if we can actually do tests around their waters?

Leung: So, this is another line of evidence. We should have a third party to engage in testing their treated wastewater, and also after dilution, the concentration as well. At the same time, we should measure those contaminants of concern in the environment.

Chan: Right.

Leung: As I mentioned, in sediment, in biota, and also in seawater. That is a good measure to look at the situation. However, since the pollutants are being discharged into environment, this will be a long-term process, in terms of bioaccumulation, biomagnification. So, there is uncertainties. To safeguard our citizens’ health, it is very important for us to do the measures, such as tighten the monitoring. All the aquatic products imported from Japan to Hong Kong, we will do the subsampling for all batches.

Chan: Right. So, professor, as you know Hong Kong people love Japanese food, and someone call Japan as basically a second home to many Hong Kong people. And they frequently dine out at Japanese restaurants when they want to travel to Japan. Should they be concerned about the situation? I mean this is going to be like dropping a bombshell into everyone, well, no more Japanese food. I mean what do you say?

Leung: I want to assure all the citizens that all the imported Japanese food are safe for consumption, in terms of radioactivity. So, we shouldn't worry about this. Since we already have the safety measures in place, now all the imported food to Hong Kong are safe for consumption.

Chan: So, in that case, if you go to Japan and have Japanese food there, you can’t be sure? Is that what you are saying?

Leung: It depends whether you have all the information about where the source of those food.

Chan: Right. Any more suggestions to the viewers? Because I mean will the frequency of consuming Japanese food or any type of Japanese food will be more likely to have a chance of contamination?

Leung: Just based on some fundamental scientific principles, also applied to other chemical contaminants, not just radionuclides, so our suggestion is we should avoid those product from the top predator, like the big tunas, shark, and those top predator species. Since they have a higher chance to accumulate and have a biomagnified concentration of pollutants, so we should eat less and moderately, so try to avoid those main sources.

Chan: Right. Or reduce frequency of consumption helps as well? From a scientific point of view.

Leung: Yes, of course. If you only eat once a while, then the risk is lower. 

Chan: Yes.

Leung: However, if you eat every day, then the chance will be higher.

Chan: Right. As you know, as the chairman of the Advisory Council on Food and Environmental Hygiene, the government has been putting effort into ensuring food on our plates are safe. Have any abnormal test results ever been found in recent months?

Leung: So far so good. So, we don’t detect any abnormal situation.

Chan: Right. Professor, let's have a break now and viewers, stay with us, we will be right back.

Chairman of the Advisory Council on Food and Environmental Hygiene Kenneth Leung attends the Straight Talk show on TVB, Sept 12, 2023. (PROVIDED TO CHINA DAILY)

Chan: Thank you for staying with us. And we have Professor Kenneth Leung talking to us about whether it is safe to consume imported Japanese seafood in light of the release of the treated radioactive water from the Fukushima power plant. So, Professor, in the first half, you have told us that we have to be very careful because there is more than tritium in the water. But in Hong Kong, it is very safe because the Hong Kong government is monitoring by sampling, that we should be relaxed about having Japanese food in Hong Kong. And actually Tse Chin-wan, the secretary for environment and ecology, said he still eats Japanese food and only chooses those products that are proved to be safe. So, from your opinion, with all the government’s monitoring works, such as they will conduct data analysis and they will release results to the public every 1-2 months. Is that practical and is it efficient?

Leung: Yes, I think so. Since we do a lot of sampling and analysis every day, then we have a huge database from now onward. So, then I think we should disclose the results to our citizens to make them calm, and also feel safe to consume our food.

Chan: Do you feel that all these extra work being done because of Japan releasing the radioactive wastewater, is it causing Hong Kong citizens a lot of money in terms of resources?

Leung: Based on the estimation from the government, we spent HK$10 million more per year for this kind of measures. I think it's a good spending because we can safeguard our health, which is far more important than money.

Chan: Right. Professor, you being a scientist, I mean it is very good privilege that we have you on the show. And I’d like to ask you more on the marine ecosystem. With this release of the nuclear wastewater, how is it going to affect the actual marine ecosystem, as I mentioned? And the biodiversity in the water there?

Leung: Although the wastewater will be diluted and then the concentration of tritium will meet the discharge standard, okay? Then we do know that there will be some other radionuclides contaminants within those water. Then they release it day by day to the ocean. And then through the current gravity, then some of these chemicals will end up into the sediment. And then the marine life will have a chance to contact them and also uptake them through bioaccumulation. And then some of the radionuclide, like caesium, strontium, we know that they could be biomagnified through the food web. For instance, in May, there was a fish being found with caesium exceeding the safety limit by 180 times. So, this is one example showing that although we discharge in low concentration, then through time and the food web, then maybe one day some fish will have a high concentration in their body.

Chan: As you have mentioned earlier in the first part of a show, having the water being released over the next 30 years with the accumulating effect is quite worrying in terms of for the ecosystem, isn’t it?

Leung: Yes, yes.

Chan: Since we … we will ask you more questions on this matter because as you know, there will be wastewater releasing from some other nuclear plants elsewhere in the world. How is it the Fukushima power plant wastewater different to the other nuclear plants?

Leung: This is a very good question. For normally safely operated nuclear plant, they do generate some wastewater from the maintenance. When they do the maintenance, they may detach some parts of the system, release those wastewater. The volume is small. And then secondly, they only contain mainly tritium, unlike the Fukushima nuclear plant because the water has direct contact to the reactor. And then they receive over 60 different types of radionuclides in those wastewater. So, we are talking about the composition is different, and also the volume is different. And then now the discharge frequency is very different. For normally operated nuclear plant, they only release those wastewater once or twice per year. But now in Fukushima, you release every minute for more than 30 years. So, it's a very different ball game.

Chan: Right, thank you very much for clarification because I read on some literature, they are saying that actually around different nuclear water plants, they do release the wastewater with tritium. And they are saying that the tritium level is actually higher than those from Fukushima. But as you said, it is a completely different ball game altogether because it is the frequency and the composition as well.

Leung: Yes.

Chan: So, what you are saying is that rate of discharge is going to cause a potential huge shift for the marine ecology and food safety. What can we do to mitigate it, apart from testing on this side? What else can we do outside?

Leung: So, I want to add one more concern, it is that right now this wastewater treatment system, the advance liquid processing system in Japan is still very new, so its performance will be good. And then we shouldn't expect any exceedance in their diluted wastewater. However, if you are running the treatment plant for many years, then there will be possible failure in the system because of machine wears and tears, and also machine failures, and even operators’ mistakes. Those may result in poor quality of the treated water, leading to more severe pollution. So, this is another concern, that's why we have to monitor for longer term, okay? You are correct that we do need to keep our eyes on the situation, and then we hope that Japan will allow the IAEA and other third parties to set foot in, to do tests, side-by-side. If those data are matching with Japan’s Tokyo electric power company’s data, then that will regain our confidence.

Straight Talk presenter Eugene Chan (left) speaks to Chairman of the Advisory Council on Food and Environmental Hygiene Kenneth Leung on TVB, Sept 12, 2023. (PROVIDED TO CHINA DAILY)

Chan: I am sure the Japan government is also concerned about this and I am sure they have been doing measures and protocols in trying to manage and mitigate the impact. So, do you believe the measures are sufficient to date?

Leung: Ideally, Japan should keep those treated water within their continent, within their country. They can either immobilize them in solid and then store them, or they can put them in their ground water system, or in an artificial lake. Then it won’t have a problem to pollute the ocean of the entire world. So, this is the best approach. Of course it will cost money. If we can't do anything, I think then we have to make sure the treatment system working really effectively to minimize the impact to the environment.

Chan: Right. We all know that there's a saying: there's many ways to skin a cat. Apart from pouring it into the ocean, there are other ways that you have just mentioned. Maybe you can tell the viewers, for example, if an accident or something like that happened, what are the options that any country has, apart from having it treated and diluted and pouring it into the ocean? Are there any other options as well?

Leung: Of course, there are more advanced technology coming up in the future, like electrolysis. But you still require bigger land space to store the water before the treatment. Why did the Japan government really want to get rid of those wastewater? Because they still need to decommission, inactivate the reactor, so that they can solve the problem for long term because right now the reactors still active, will generate thousand tons of contaminated wastewater every month. So, then, however, they need a space to decontaminate the plant. This is a kind of dilemma they are facing. No matter what kind of treatment, they still need space to hold the water and treat the water.

Chan: Just now you also mentioned costs as an issue. I also read some report, actually treating this wastewater, after treated and pouring it in the ocean is the most economical way. I mean of course, all countries should be economical and be optimal. But in your opinion, is that the most optimal result to do this by pouring the wastewater into the ocean?

Leung: If the Japanese government worries about the consequence to their fishermen, to their neighborhood countries, I think it is a very smart way to spend more money to keep the wastewater in their nation, because you have to look at the … I mean as a whole, holistically in this issue. It is not just a short term game, it is more a long term benefit to mankind. 

Chan: Right. Professor, how can we … given this is going to happen, how can we transparency and accurate information dissemination to the public, from your point of view?

Leung: So, I really hope that the Japanese government will allow the third parties to do the tests in Fukushima nuclear power plant side by side with their own team. Then this will help us regain the confidence on their system.

Chan: Right. We have a last question for you on the show. Because Hong Kong and the Chinese mainland are the main sort of speaking out on this issue, but other countries have been fairly quiet or they may not be aware. From your point of view, why is it, even the US government, is not concerned about this discharge of nuclear wastewater into the ocean?

Leung: I think the IAEA is playing the major part to endorse this treatment system. They provide a very detailed analysis in their report, saying that if Japan government does ABCDEFG measures, then the water, after dilution, should be safe with lower risks. So, then if they can follow the book and doing well in the treatment system, then they can minimize the risks. This is for everyone want to see, everyone will be happy to see. So, I think if you take this position, then we will say that we should support the Japanese to do a good job, so that make sure the impact to the environment and human health would be minimized. 

Chan: Right.

Leung: However, we need more data, third party data, to assure the outcome.

Chan: Thank you, Professor Leung, for shedding light on the important issue of import of Japanese seafood safety. It is evident that both governments, agencies, industries and stakeholders in Hong Kong are actively working to ensure that the seafood on our plates safe for consumption. 

Viewers, I’d like to leave you with a quote from actress Audrey Hepburn: “Water is life, and clean water means health.” Have a good evening and see you next week!