Fukushima fish with 180 times legal limit of radioactive cesium fuels water release fears
Black rockfish caught in May close to disaster-hit nuclear power station is one of dozens caught in the past year above the legal safety limit
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We probably should measure around France too, they seem to release 500 times the amount of water to the sea https://www.cn.emb-japan.go.jp/files/100194021.pdf
A total of 44 fish with cesium levels above 100 becquerels per kg have been found in the Fukushima plant port between May 2022 and May 2023, Tepco confirmed, with 90% of those caught in or near the inner breakwater.
Is the article really talking about 44 fish?
There is a difference between contaminated water, like in Fukushima, and regular non-contaminated cooling water. There should be no radioactive contaminants in the water that the French nuclear power plants release.
Well actually cooling water is bombarded with neutrons, which transforms hydrogen atoms into deuterium and radioactive tritium. It's just generally regarded as harmless (probably because there's no good way to test for bioaccumulation.)
Depends, I didn't see the total number of fish sampled.
If it was 44 fish out of 44 sampled, than 100% being over the limit is significant.
If it was 44 fish out of 1000+, than not so much.
44 fish out of 1000+ might be extremely significant.
If we’re going to say “what is the likelihood of pulling up a fish with 180x cesium levels?” then the number 44/1000+ might seem like we should say “It’s not very significant.” And for some phenomena, that’s an okay assessment. It’s the same as 4.4/100+, which is a less than 5% chance. Of course, having a 5% chance of getting shot on the way to work is a bit high. It probably means your work is being in active combat.
You also have to measure downstream effect. If there were 44/1000 and 1000 was the average catch size, that means that for a single catch, 44 fish that I can only assume are poisonous or at least medically dangerous. How many people would those 44 fish serve? Could we expect 50-60 downstream deaths or cases of cancer? How many shipments of 1000 fish, with 44 having 180x cesium levels, are going to make their way into the coastal cities and food distribution in the area?
But even beyond all of that, you cannot look at a statistical number intended to characterize something like this and make an interpretation as to its significance without more data. In this case, the number we’re measuring significance against is “Out of x fish, how many do we expect to have 180x cesium?” If the answer is “40,” then 44 is likely not significant. If the answer is “less than 1,” then I suspect 44 is extremely significant. It’s multiple orders of magnitude from baseline, which means that something very very different and quite possibly unexpected and extremely bad is going on.
Basically - and I’m not accusing you of this in any way - some people will use this kind of non-analysis to deliberately mislead their readers about health or safety or environmental issues. It’s nothing against you, OP. It’s just that I taught and still sometimes teach this kind of thing, and I want to make sure that people are aware when they read this sort of thing.
The 1000+ number was just a random number. It was simply to highlight that the article never mentioned the total numbers sampled, just the total numbers found to have the high levels.
I don't doubt it was 44 out of 44, or that 44 out of 1000 is a lot as well, it simply wasn't the point that I was trying to make.
My point isn’t about 1000 or 10000. It’s that we shouldn’t make assumptions as to the interpretation of statistical characteristics without sufficient additional data.
Let me know if I'm wrong (certainly possible) but I feel like if we found ONE fish with 180 times the legal limit of radiation, it would warrant a closer look. 44 fish found in an area that had a nuclear disaster sounds like more than enough samples to raise concerns.
(And I don't really know about France, but sure if there might be a problem there too, I vote we check that out too.)