Scientist rejects Fukushima wastewater outcry

To Japan now, where the owners of the country’s badly damaged Fukushima nuclear power plant have begun releasing a second batch of treated radioactive wastewater into the sea. The wastewater will continue to be released for decades to come and it has prompted a furious response from fishing groups and neighbouring countries - including South Korea and China. The story goes back to 2011 when, in the aftermath of a massive offshore earthquake, an ensuing tsunami took out the plant’s power supply and caused three of the reactors to melt down, contaminating the site. Authorities there have cleaned up the site, but… from Portsmouth University, environmental scientist Jim Smith...

Jim - Since then, the Japanese have been storing what's called treated wastewater; water that's been produced from the cooling of the reactor on the site, rainwater that's filtered through the reactor buildings and is in groundwater, which has been pumped out. All that slightly radioactive water has been treated and stored in about a thousand giant tanks from the Fukushima site. In August of this year, 12 years after the accident, the Japanese decided to start discharging this treated wastewater into the Pacific Ocean. And this has caused a lot of controversy because some people have claimed that it's going to damage the ocean and marine ecosystem and it's going to damage people eating seafood from the Pacific. So I and a couple of colleagues in Australia wrote an article in the journal Science about why we think the scientific evidence shows that this release of treated wastewater isn't a risk to the Pacific.

Chris - What's actually in the water, Jim? If we analyse it, what sort of radioactive material are we talking about?

Jim - The water has been contaminated by things that are in the reactor core when it had its meltdown. So after both the Chernobyl and Fukushima accident, one of the main contaminants was a thing called radioactive cesium. Radioactive cesium can be damaging in the environment, but it's also relatively easy to treat in wastewater. So the Japanese have set up things called ion exchange columns, which take out the radioactive cesium and many of the other radioactive elements in the wastewater. What they can't strip out is a thing called tritium. So tritium is a radioactive form of hydrogen. And what happens in nuclear sites all over the world is that some of the water passing through the reactive becomes what we call tritiated. In other words, instead of having H2O, which is ordinary water, one of the hydrogens is replaced by its radioactive form tritium. So it becomes a thing called HTO, hydrogen tritium and oxygen. And the thing about tritiated water is, chemically, it's identical to ordinary water. It behaves exactly the same. And that means that it's incredibly difficult to take it out of the wastewater because chemically it can't be distinguished from all that massive ordinary water. In the thousand or so tanks at Fukushima, there's 1.3 million tons of water. Within that, there's about three grams of tritium. So separating that three grams is really, really difficult. And so what nuclear sites all over the world do with tritiated water is that they release it into the local river or lake or in into the ocean.

Chris - So what's the scale of the threat that that may pose?

Jim - Before it goes down the pipeline at Fukushima into the Pacific, it's diluted a hundred times. We measure radioactivity in becquerels. So there are 1,500 becquerels per litre of tritium in the wastewater when it's released. And just to get an idea of what that means, the World Health Organisation drinking water limit for tritium is 10,000 becquerels per litre, so about seven times higher. So it's really at a very low level. The other radioactive elements will be at less than 1% of the Japanese regulatory limit for discharge to the sea, which is already quite cautious. So in terms of what we expect to see from this release, we don't expect to see anything. Radiation doses have been calculated, not just from the tritium but from all the others. There are trace amounts of other radionuclides in the release. And even to people who are consuming seafood from that local area, the dose is about 2000 times less than the radiation dose that we all get from natural radioactivity in the ground, in the air, cosmic rays. So it's a really incredibly low dose. It equates to about a quarter of a dental x-ray.

Chris - I think one commentator put it that it's about a thousand times less than you'd get just flying from London to LA. So Prince Harry, every time he pops over to London to sue a newspaper, he gets a dose a thousand times bigger than you'd pick up from this.

Jim - Yeah, it's trivial compared to air radiation. So when we go above the atmosphere, we're exposed to more cosmic radiation, so frequent flyers can get significantly higher doses than other people just because they're above the atmosphere, and air crew as well.

Chris - So given that this actually appears in the grand scheme of things to be such a low risk, why has there been so much vocal opposition? Particularly, for instance, from China, because as one other person pointed out, the amount of operating coal fired power stations in China that are releasing radiation into the air, just by virtue of the fact you're burning something that contains trace amounts of radioactivity in the coal that you burn, China are releasing far more than this on a daily basis.

Jim - That's right. And China, of course, has lots of nuclear power stations which are also releasing more than this. So there's a nuclear power station in China that emits about nine times more tritium annually into the Pacific than this Fukushima release will do.

Chris - So why have the Chinese been so vocal against it? They've made quite a song and a dance about this.

Jim - I'm a scientist. I'm not a politician, but this has to be about politics. It's certainly not based on scientific evidence. In the Pacific, there are real environmental issues, which is climate change, plastic pollution, raw and treated sewage going into the Pacific, overfishing, there are real major environmental problems in the Pacific. And this Fukushima release is just not one of them.