| On 11 March 2011 a magnitude 9.0 earthquake triggered a tsunami that knocked out the backup electricity supply at the Fukushima Daiichi nuclear power plant on Japan’s north-eastern Pacific coast, leading to meltdowns in three of its reactors. Ever since, 1.34m tonnes of radioactive water has accumulated at the site, according to the plant operator, Tokyo Electric Power Company (Tepco). This includes liquid used for cooling, plus rain and groundwater that has seeped in. Earlier this year, Justin visited the site, and saw the thousand or so steel tanks being used to house the contaminated water (pictured above). “They’re three storeys high and are all together across a wide area,” he said. Tepco says it will soon run out of storage room and this week was granted permission to start releasing “treated” water from the tanks into the Pacific Ocean. The plan has caused controversy because the water contains tritium, a radioactive form of hydrogen that can’t be removed by the facility’s water filtration technology. It will not be pumped out all at once, but over the next 30 to 40 years. The first discharge, starting on Thursday (weather permitting) will total 7,800 cubic metres over about 17 days, Tepco said. For those of you not great at visualising volumes, that’s about three Olympic swimming pools. Is it dangerous? The International Atomic Energy Agency (IAEA) has approved the discharge, saying that the radiological impact on people and the environment would be “negligible”. The levels of tritium will be 1/40th of the legal level for discharges, Tepco insists, and has promised to upload hourly data on water quality. The scientific consensus has persuaded Justin that “as long as you are exposed to tritium in low doses, it doesn’t represent a threat to human health”. Greenpeace, however, has described the filtration process as flawed, and warned that an “immense” quantity of radioactive material will be dispersed into the sea over the coming decades. Concerns have also been raised by the Pacific Islands Forum (PIF), the main intergovernmental organisation representing the region, which has been consulting with Japan over the release for the past two years and in January said it had “grave concerns” over the plans. In June, the PIF issued a statement drawing attention to international laws against dumping nuclear waste in the Pacific. Justin has come to the view that storing the water indefinitely is not a realistic option: “When does it end? What are you going to do with 2m tonnes, 3m tonnes? What about a leak? That area gets tsunamis, it gets quakes, it gets typhoons. What if something like that were to happen and lots of the tanks were damaged?” But much remains unknown. Justin asked a “very sensible” anti-nuclear expert if it would be safe for him to go swimming in the sea in Fukushima in September. The expert said yes, but that the problem is not swimming but “organically bound tritium – over the years, when it gets into seaweed, shellfish or fish and then consumed by humans over a long period. What does that do to human health? It’s difficult to say.” The fallout | 