Let people decide what constitutes "acceptable risk" for themselves

With regard to radiation exposure, “safe” really means an “acceptable level of risk,” and not everyone agrees on what is acceptable. The Japanese government has set an annual effective dose limit to the public of 20 millisieverts (mSv) per year above background as its remediation goal for the Fukushima Prefecture – up from one mSv per year, which was the official limit for exposures to the public prior to the incident.

These arbitrary-feeling radiation levels can seem very abstract to the general public. Rather than moving the dose limits around, the Japanese authorities would be better off to just explain what the actual cancer risks are at the various radiation doses and let people decide for themselves if they want to go back to their homes.

For example, receiving an annual environmental dose of 20 mSv is similar to having a single annual whole-body CT scan for medical diagnostic purposes. Epidemiological evidence indicates that the lifetime cancer risk from a single whole-body dose of 20 mSv is about 0.1 percent (or odds of 1:1,000). Put another way, if 1,000 people received a dose of 20 mSv, just one would be expected to develop cancer.

Maybe a better way would be to compare this with natural background levels in different parts of the world. I found this one :

But since it's pinterest there's no source and I make no claim to its accuracy. Also, radiation seems to have a horribly large array of different units to measure dosage.

Regulatory limits don’t represent thresholds for safety. The limits are merely arbitrary lines that are drawn in the sand by some regulatory body, marking the fuzzy border between the dose levels that entail “acceptable” versus “unacceptable” amounts of risk. If you don’t like where that line has been drawn, pick up a stick and draw a different line for yourself. When it comes to risk tolerance, different people will always draw different lines.


https://theconversation.com/acceptable-risk-is-a-better-way-to-think-about-radiation-exposure-in-fukushima-56190