Is radioactive iodine in water/food comparable to flight exposure?

[Go2Peace]

I keep seeing these two comparisons. But I am not sure they are comparable? One is how much radiation hits you externally, I doubt most of that radiation would be measurable inside the human body. Or would it?

So is the claim that a certain level of millirem in iodine in potential food or water sources really comparable to what you are exposed to in a flight? Can someone clarify?

Thanks

[darkstar3]

1. The comparisons are difficult to follow at first.

The reason for the comparison is due to I-131's short halflife. If you are exposed to a certain level of I-131, then you can estimate your total CUMULATIVE radiation energy exposure from that dose of I-131 decaying completely to inactive. Once you know that cumulative dose, you can compare it to the cumulative dose given by a plane flight.

Radiation doesn't care about external or internal. It's energy, and it tends to penetrate you straight through.

[wtmusic]

2. Energy "tends to penetrate you straight through"?

Sunlight is energy, and that doesn't penetrate you straight through.

Beta emissions from I-131, which cause 90% of its damage to tissue, have a maximum penetration of about 2mm. So it is far more dangerous when ingested and absorbed by the thyroid gland.

[darkstar3]

3. It's true my point about "straight through" was specifically about gamma rays,

but that's the type of radiation most people think of when they hear the generic term "radiation."

Of course, the point about cumulative dosage is still the reason for the post, but if you want to quibble over types of radiation go right ahead.

[wtmusic]

4. I only quibble with accuracy

and your post is wildly inaccurate.

If you don't absorb radioactive iodine your cumulative dose is a fraction of what it is if you do. That's why people are given iodine tablets - to saturate the thyroid with stable iodine and prevent absorption of radioactive isotopes.

I have no idea why you think most people think radiation refers to gamma rays; most people don't even know what gamma rays are. In any case, they only cause 10% of I-131's tissue damage. It's relatively low-energy beta decay that makes I-131 far more dangerous when ingested and absorbed. In that sense, it "cares" very much about internal/external.

Bottom line: you can largely prevent radioactive iodine damage by not ingesting it (not consuming contaminated milk or leafy vegetables) and taking iodine tablets.

There's nothing you can do on a plane flight to limit your dose of gamma radiation from the sun.

[darkstar3]

5. No, it really isn't.

I simply didn't include the information about MITIGATING doses. The tables at various scientific sites contain information comparing I-131 contamination, which assumes FULL absorption, to cross country plane flights. I was explaining the rationale behind the assumptions of cumulative, full absorption, dosing, as was asked for in the OP.

Yes you CAN mitigate the dose. I never said you couldn't. I do, however, think that mitigating a dose that will expose you to the radiation energy equivalent of <1/124 of a flight from SF to DC is pointless, and worrying over nothing.

As for people thinking of gamma rays when they hear the term "radiation", if you don't understand common misconception then I don't care to talk to you.

[DCKit]

6. "...but if you want to quibble over types of radiation go right ahead."

As I understood it, that WAS the question.

There is little similarity between the types of damage from ingested sources of gamma AND neutron radiation and that from gamma, UV and X-rays (supposing you were flying on the wing).

[TheMadMonk]

7. Same but different is about as best it can be put.

When it all comes out in the wash, a given adsorbed dose will give a similar severity of outcome however it is received.

Some forms can be mittigated, some avoided, and most of what we receive, we take without ever paying attention at all.

The regulatory thresholds are set so far (3-4 orders of magnitude) below the measured saftey thresholds, that the sort of environmental exposures being experienced in Japan right now are not of any measurable concern. Even the too "hot" for babies drinking water was a storm in a teacup, since water equally "hot" would have to be exclusively given to them for a full year to receive an unacceptable (much, much less unsafe) dose.

The absolute emergency limit permitted to workers before being retired is in fact only just barely (2.5x) above the lowest threshold at which the deletrous effects of radiation exposure are statistically detectable with any reliability.

What's happening to the general public is not even on the radar. It might be possible to infer through extrapolation that in a sufficiently large (tens of millions) population there will be some calculable effects from even miniscule levels of exposure. However, no statistical trick will ever be able to prove/detect the existence of such a small anomally.

[DCKit]

8. Radioactive Iodine is absorbed by, then kills the thyroid gland.

Just how much of the thyroid gland dies depends on the dose. However, I would think that we are each born with just as much thyroid gland as we need - No more, no less. You start screwing with hormone levels at infancy (and the teeny, tiny thyroid gland of an infant), and those kids are going to need medical support for life.

Additionally, that's just one of several dangerous elements with long-term effects on everything from bones or muscles (including the heart) as well as those that are both toxic and radioactive.

If I didn't know these things, I'd have bought a gigantic spread next to Chernobyl ten years ago. I hear land is kinda cheap in those parts.

[darkstar3]

10. It only kills the thyroid gland DUE to the radiation given off.

If the CUMULATIVE dose of radiation given off by the radioactive iodine barely measures in comparison with a day in the sky, how can that be more dangerous to the thyroid than, I don't know, living your life?

[DCKit]

11. The sky is not IN our thyroid glands.

Our skin is enough to protect us from most common, external radiation. It's the difference between laying in a tanning bed for 20 minutes or swallowing the lit, UV lightbulb.

Radioactive strontium, cesium and iodine are taken up by bones, muscle tissue and the thyroid gland and do their damage from the inside, where there are no layers of skin and fat between the vital tissues and the outside world.

If you won't take it from me, please use your computer to do some research. These arguments were old three days after the accident.

[csziggy]

9. This chart does a really nice job of visually comparing dosages of radiation

Though it is not up to date on the more recent levels measured at Fukushima or the readings at various specific places in the US.


http://xkcd.com/radiation/

[DCKit]

12. Comprehensive Wiki article on the different TYPES of radiation.

All of which can be expected, in varying degrees, from Fukushima:
http://en.wikipedia.org/wiki/Radiation