Don't eat glowing snow

[Craig]

As is evident from our own sampling and as the national expert agencies such as the Nuclear Regulatory Commission and the Environmental Protection Agency have advised, the radiation released from the Fukushima nuclear accident in Japan does not pose a direct risk to the citizens of New Hampshire," said Jose Montero, director of Public Health.

A fresh snow sample collected and analyzed over the weekend showed trace amounts of radioactive iodine (I-131) measuring 18 picocuries per liter. A previous measure reported on March 28 showed 40 picocuries per liter. Neither of these levels is considered a public health risk, the state said.

UL Article

I think I'll rely less on trail sources of water this year.

 

[vegematic]

I wonder why they tested for iodine and not cesium which has the much longer half-life (decades rather than days).

 

[J.Dub]

I didn't follow the link to the article, but I-131 has a half-life of 8 days, so by the time next winter rolls round, I think you'd be pretty safe there, Dr. Strangelove...

 

[DougPaul]

The federal standard for I-131 is 4600 picoCuries/Kg (=4600 picoCuries/liter of H2O) and the article talks about levels of 8 and 20 picoCuries/liter for the snow. And as J.Dub noted, the half-life of I-131 is 8 days. http://www.dhmh.state.md.us/pdf/iodine 131 fact sheet.pdf

I think you will live, even if you drank nothing but melted snow for the next year.

Doug

 

[Raven]

I wonder why they tested for iodine and not cesium which has the much longer half-life (decades rather than days).

Hi Veg.

IIRC I-131 is a product primarily specific to nuclear fission reactors, not natural sources. Also, the short half life of 8 days is exactly why we know it had to come from a recent meltdown. Radioisotopes with longer halflifes could have come from sources farther back in time.

When it's found, it's a sign of a recent fission problem. Not that they can really be hidden well anyway.

 

[TEO]

UL Article

I think I'll rely less on trail sources of water this year.

All the more reason to treat your water with iodine.

 

[Dr. Dasypodidae]

Radioisotopes with longer halflifes could have come from sources farther back in time.

For example, we use Cs-137 as a chronological tool for dating near-surface lake sediments and ice cores, as the global atmosphere got dosed heavily with Cs-137 and other isotopes from atmospheric bomb testing in the 1950s and 1960s.

 

[vegematic]

Hi Veg.

IIRC I-131 is a product primarily specific to nuclear fission reactors, not natural sources. Also, the short half life of 8 days is exactly why we know it had to come from a recent meltdown. Radioisotopes with longer halflifes could have come from sources farther back in time.

When it's found, it's a sign of a recent fission problem. Not that they can really be hidden well anyway.

Thanks for that. I was thinking they'd want to know about the longer-lived isotopes as they would be more dangerous (screwing things up for longer), but pinpointing the source makes sense.
-vegematic

 

[TCD]

Another reason to test for Iodine, as opposed to another nuclide, is because Iodine is preferentially taken up by the Thyroid, so the presence of that radioactive species might be more apt to affect human health than some other species.

 

[Raven]

Thanks for that. I was thinking they'd want to know about the longer-lived isotopes as they would be more dangerous (screwing things up for longer), but pinpointing the source makes sense.
-vegematic

You're absolutely right about isotopes with longer half-lives - they release the radiation a lot longer and are more dangerous, assuming both release gamma radiation. Alpha and beta radiation aren't as bad.

 

[TCD]

If I am reading the Chart correctly, I-131 decays by beta and becomes Xe-131. Cs-137 decays by beta to Ba-137m; but Ba-137m decays quickly (2.5 minutes) and is a gamma emitter.

 

[DougPaul]

You're absolutely right about isotopes with longer half-lives - they release the radiation a lot longer and are more dangerous, assuming both release gamma radiation. Alpha and beta radiation aren't as bad.

Actually, isotopes with [much] longer half-lives can be safer--they only emit a small fraction of their radiation within a human lifetime. In effect, a stable isotope is one whose half-life is too long to measure.

BTW, beta radiation (electrons) may be less risky when it is external to the body, but can be very dangerous when the isotope is inside the body. It causes cell death and mutation over a range of several mm.

IIRC, the riskiest isotopes for humans in a typical reactor release (eg Chernobyl) are :
* iodine-131 (8 days, beta, absorbed by the thyroid gland) http://en.wikipedia.org/wiki/Iodine-131
* caesium-137 (30 yrs, beta followed by gamma, salts dissolve in water and mimics potassium, distributes throughout the body--biological half-life 70 days) http://en.wikipedia.org/wiki/Caesium-137
* strontium-90 (29 yrs, beta, dissolves in water and mimics calcium and collects in the bones) http://en.wikipedia.org/wiki/Strontium-90

Plutonium dust is also extremely dangerous--if a particle is breathed in, it can lodge in the lungs and cause cancer.

Doug

 

[Raven]

Actually, isotopes with [much] longer half-lives can be safer--they only emit a small fraction of their radiation within a human lifetime. In effect, a stable isotope is one whose half-life is too long to measure.

BTW, beta radiation (electrons) may be less risky when it is external to the body, but can be very dangerous when the isotope is inside the body. It causes cell death and mutation over a range of several mm.

IIRC, the riskiest isotopes for humans in a typical reactor release (eg Chernobyl) are :
* iodine-131 (8 days, beta, absorbed by the thyroid gland) http://en.wikipedia.org/wiki/Iodine-131
* caesium-137 (30 yrs, beta followed by gamma, salts dissolve in water and mimics potassium, distributes throughout the body--biological half-life 70 days) http://en.wikipedia.org/wiki/Caesium-137
* strontium-90 (29 yrs, beta, dissolves in water and mimics calcium and collects in the bones) http://en.wikipedia.org/wiki/Strontium-90

Plutonium dust is also extremely dangerous--if a particle is breathed in, it can lodge in the lungs and cause cancer.

Doug

Good points Doug.

Something like K-40 has a halflife of over a billion of years. You won't get a high concentration of radiation emitted from that. That's a natural one and in salt. Americium-241 I believe is the one found in the smoke detector. That one's basically harmless too but it might (?) be an alpha emitter only.

Don't mean to imply beta isn't bad, just lesser of two evils usually when compared to gamma simply for the distance gamma travels and its much stronger penetrability. You definitely don't want to be real close to a beta source though (e.g ingesting or close to the body). They're high energy, as are alpha. Luckily though, beta's not going to get through a thick sweatshirt let alone anyting substantial. Ingesting them would be bad.