Thread: 1/ There will be a lot of talk in the coming weeks about the Japanese Government planning to dispose of radioactive wastewater at the #Fukushima Daiichi nuclear plant site in the ocean. Much of the focus will be on a form of radioactive hydrogen called tritium
2/ Tritium is difficult to remove from wastewater at the site because it is largely present in the form of the water molecule itself and therefore resists traditional methods used to clean/extract contaminants
3/ The amount of tritium (1 PBq) stored in the #Fukushima Daiichi wastewater tanks is very small compared to the amount still in the ocean from nuclear weapons testing in the last century (8000 PBq) or
4/ the amount present naturally from cosmic ray reactions with the atmosphere (2000 PBq)
5/ The risk to environmental or public health from this amount of tritium is likely to be very small
6/ Our collective concern and a proper accounting of risk related to ocean disposal of this wastewater should consider the other isotopes present like for e.g. 90Sr and 137Cs which persist longer in the environment and can concentrate in living organisms.
7/ How much of these isotopes remains in the tanks after treatment varies and should be better constrained by measurements by neutral parties in order to properly evaluate risks
8/ The risk of storing the isotopes on site where their activity (except for long lived isotopes like 129-Iodine) will diminish along with risk with time as they decay versus an accidental release at the site due to tank failure, human error or natural disaster must be weighed
Thread 1/ #Typhoon Hagibis made landfall in #Japan and has caused widespread flooding with human lives lost. Spare a thought for those in Japan who need help at present. #Fukushima Daiichi. But some are using this storm to promote scientific misinformation
2/ I am seeing posts that link the #radioactive contamination/decay heat from #Fukushima Daiichi & the development of tropical cyclones like #Hagibis and going so far as to say the human caused global warming is not like to #CO2 but nuclear fallout/contamination
3/ The argument goes something like this and is summarized in a blog I posted some time ago @dailykosdailykos.com/stories/2016/1…: 1. Fukushima released radionuclides to the environment with much of the contamination ending up in the Pacific Ocean 2. Isotopes generate heat on decay
Thread 1/ Some recent results of @FukushimaInFORM monitoring project which is tracking contamination from #Fukushima in Canada and the Northeast Pacific Ocean off North America fukushimainform.ca
2/ This figure compares levels of Cesium-137 (half life ~30 years) measured in salmon collected from the Northeast Pacific post #Fukushima with levels measured in 1967 just after atmospheric nuclear weapons testing was halted by the introduction of the Comprehensive Test Ban
3/ In 1967 levels of 137-Cs in Pacific seawater were ~20 times higher than peak levels we saw off North America post #Fukushima. Salmon in the mid-1960s were much more contaminated then levels we see in fish 2014-2018 returning to North American rivers to spawn
Thread: 1/ Team members of @FukushimaInFORM have been monitoring the impacts of the #Fukushima disaster on marine and public health in Canada since the meltdowns at the Daiichi nuclear power plant in 2011
2/ We have a new paper in press summarizing our work looking for #Fukushima contamination in almost 300 #Pacific salmon collected near to North America in 2013-2016 returning to the rivers shown below
3/ Here is what we found. Pacific salmon always have a naturally occurring radioisotope in their flesh called Polonium-210. 210-Po has a half life of 138 days and is produced by the decay chain of Uranium-238. 210-Po was discovered by Marie Curie in 1898
1/n Thread: Routinely people write or tweet at me that #Fukushima is still leaking to the ocean and therefore contamination levels in #Pacific seawater and marine organisms must be increasing. This is just not so.
2/n My reply is that rates of releases now are so low compared to March-April 2011 that one can barely detect that #Fukushima is leaking at all into the ocean even near to the Japanese coast. Colleague Michio Aoyama has just published a peer-reviewed paper showing just that
3/n He and his team of experts measured 137-Cs and 134-Cs from #Fukushima in the following locations in #Pacific seawater from 2011 to 2017. You can see that boxes 1, 2, and 3 are closest to the Japanese coast with box 1 off #Fukushima prefecture