To keep the risk below 1×10-5 the consumer must limit his/her dietary intake to less than 10,000 Bq of cesium-137. Therefore this risk limit would be reached after eating about 0.7 kg of fish meat. While this is a conservative estimate of what is required to achieve a low risk, one could make a good case for quarantining fishing off the Japanese coast near Fukushima, which of course is what the Japanese government has done.
The risk would increase as more fish is eaten. The article goes on to say that the risk is much lower than fish caught off the coast of the US, but there are also reports of tuna found off the coast of California having low but detectable levels of cesium 134. The article goes on to say that the plume of radioactive material has not yet gotten to the West Coast. So, there is not a problem now, but it may well be coming.
Finally, the article says that the calculations are confounded by all the other radioactivity from the atomic bomb tests. The point is often made that the levels are not significant compared to back ground levels. Since many radioactive nucleotides have long half lives, then the back ground level of radiation may well be rising. I have not seen any information about “normal” back ground levels of radiation taken back in 1944, before the “dawning” of the nuclear age.
- Fukushima Radiation Risks from Eating Fish (switchboard.nrdc.org)
- 28 Signs That The West Coast Is Being Absolutely Fried With Nuclear Radiation From Fukushima (silverdoctors.com)
- If you like fish then you better know your radiation…….. (lifehardcore.wordpress.com)