B Sievert lethal radiation doses for Non-Humans (other animals)

[Silly Questions]

Does every species get its own 5.5%-calibrated sievert?

It's morbid to ask, I know, but given that Chernobyl is full of dogs I have to ask whether there is such a thing as a dog-sievert?

 

[dlgoff]

I don't know anything about the dogs, but I do have a Sievert lethal radiation doses chart. See attachment.

 

[mfb]

For many dangerous things we know the risk for rats better than the risk for humans.

It's morbid to ask, I know, but given that Chernobyl is full of dogs I have to ask whether there is such a thing as a dog-sievert?

As long as dogs aren't suddenly 10 times more sensitive (why would they?) it won't have a big impact on them. It doesn't have a measurable impact on the humans living there either. With less mass and a shorter lifespan cancer should be even less of a concern for dogs.

 

[Silly Questions]

Is there then a rat-sievert? Either every animal for which we have data has its own 5.5% per sievert chance or [coincidence notwithstanding] it's a different % for all non-humans so that the same dose is the same sievert count regardless of species. But it can't be both.

 

[mfb]

A sievert is a sievert. The acute LD50 dose and the lifetime risk to die from cancer from a given radiation dose are different for rats.

 

[gleem]

Does every species get its own 5.5%-calibrated sievert?

What do you mean by 5.5% calibrated sievert?

 

[Silly Questions]

Per mfb's answer all species use the same, human-calibrated Sievert. This means each has its own %-chance, whatever that may turn out to be. For humans it's 5.5%.

Thanks to mfb for your answer.

 

[gleem]

This means each has its own %-chance, whatever that may turn out to be. For humans it's 5.5%.

Percent chance of what? 5.5% cannot apply to everything. You must define an end point for example the dose that 50% of people will survive for 30 days. Because human data with adequate dosimetry is so sparse these doses are only estimates. LD₅₀ only related lethality due to the radiation without medical intervention for example the denuding of epithelial cells in the intestines (gastrointestinal syndrome) and bone marrow death (hematopoietic syndrome).

The rate at which the radiation dose is accumulated is very important also. The effect of 1Sv delivered in one minute is different from that dose delivered in one week.

 

[Silly Questions]

This 5.5%:
"One sievert carries with it a 5.5% chance of eventually developing fatal cancer based on the linear threshold model."
https://en.wikipedia.org/wiki/Sievert

Per the article that model has both lower and upper bounds outside of which Sieverts no longer make sense as a unit of measure, which I think is what you were getting at?

 

[gleem]

It's morbid to ask, I know, but given that Chernobyl is full of dogs I have to ask whether there is such a thing as a dog-sievert?

OK, I got it. The US has had a program from the 50's to about 1990 irradiating beagles to study the incidence of cancer that are produced. I do not know the results of those studies but are probably available in a journal or government report. This program was no secret. I would expect that yes, the induction of cancer in dogs is different from humans after all radiation sensitivity is different among species. How much??. This information is particularly valuable at low doses and dose rates for radiation protection purposes, but experiments are more difficult since effects are lower. The beagle experiments were generally not useful for these estimates AFAIK.

I believe the ICRP report reference in the Wiki article used data analysis from the latest BEIR report (Biological Effect of Ionizing Radiation) of the National Research Council which heavily relies on atomic bomb survivor data. The analysis of this data has come under increasing criticism and could have a profound effect on the estimates of carcinogenesis so the 5.5% is in question.

 

[Silly Questions]

I vaguely remember a study back in the 1970s questioning why airline workers weren't getting cancer at rates predicted by the atomic bomb survivor evidence-based models you mentioned. Those models broke down at low enough exposure levels, but actually collecting enough data to know took decades. it didn't help that for low-level exposure the models failed upward -- though that was of great relief to airline crews I'm sure.

I'm certain you know more on DNA resilience to low-dose radiation than I do. If you'd like to expand on the topic I'd be more than interested.