Tourist exposed to Radiation at Grand Canyon

[CJ7365]

According to the article 800-1000 a year for nearly 2 decades, visitors were exposed to radiation from National Park's museum collection building



https://www.azcentral.com/story/news...ys/2876435002/

[1bigmess]

The report indicated radiation levels at "13.9 mR/hr" where the buckets were stored, and "800 mR/hr" on contact with the ore. Just 5 feet from the buckets, there was a zero reading. The abbreviation, "mR" typically stands for milliroentgen, a measurement roughly equivalent to a millirem, according to the Nuclear Regulatory Commission.

(Look up "inverse square law" to learn about the amount of radiation one might be exposed to somewhere in between 0 to 5 feet from the source. --1bigmess)

The NRC says average radiation exposure in the United States from natural sources is 300 millirems per year at sea level, or 400 at high altitude.

I toured the Trinity test site a few years ago. THis thing growing out of my neck with teeth in it likely has nothing to do with that though.

[grumpy0374]

We were there last year in May. Wife has had a strange greenish glow at night ever since. Now I know the reason why.
I should complain, but since then I don't need a night lite for my 2 am bathroom trips.

Grumpy

[FatChance]

There has been a fight over a proposed uranium mine on the edge of the NP for years. Don't you think most people would want the uranium removed from the ground and aquifers? Nope.

The ignorance about naturally occurring radiation, like most other scientific issues, is rampant these days. You get more radiation exposure just walking around in higher elevations of the western mountains due to thinner air density and native granitic rocks (and sedimentary rocks "downhill" from them) than being near that mine site or getting an x-ray at the dentist or doctor.

Yeah, my first career was as a uranium exploration geologist throughout the western US and Australia back in the 70s to the mid-80s...

[A32Deuce]

Ever since visiting there, Don't Make Me Mad!

[Dutch Star Don]

I read the article the other day and was trying to figure out where the collection building is located....it says its in the Village. We've been there about five times since it was placed there. I'm guessing someone found a few buckets of ore, removed from the Uranium mine, and thought it was something interesting for a display, but just sat all this time in a storage room.

I'm sure the exposure to visitors is not a big issue, but as a long term employee I would want to be checked. You can see the Uranium mine from one of the arms on the road to Hermits Rest. The area on top of the canyon, above the mine, is stilled fenced off and undergoing reclamation.

[Isaac-1]

I have been catching bits of articles about this all day, and this one is by far the most detailed, unfortunately it is also very sensational. This theoretical exposure risk would be for someone hugging one of these buckets. It is as if no one understands the inverse square law, and that contact readings by themselves are useless in determining exposure. Simply put for every time you double the distance, your radiation exposure goes down to 1/4 of the amount. To put that in other words 400 times the safe level at 0.1 inches is 100 times the safe exposure limit at 0.4 inches, and is 25 times the safe exposure limit at 0.8 inches, does anyone want to continue to do the math for say 2 feet which I suspect might be the closest a member of the public would be allowed to something in an exhibit? This is of course an over simplification of the matter as Uranium primary decay chain is through alpha particle and beta emissions, alpha particle emitters are primarily an inhalation hazard, which should be nearly a non issue with ore in a paint bucket since the alpha radiation can be blocked by something as thin as a sheet of paper, beta particles are not that much stronger so there is a good chance the majority would be blocked by a metal paint can, this leaves the gamma emitters further down the decay chain, which may pose a threat, though without those detailed readings how much of a threat they are is anyone's guess.

[rvethereyet]

Originally Posted by Isaac-1

I have been catching bits of articles about this all day, and this one is by far the most detailed, unfortunately it is also very sensational. This theoretical exposure risk would be for someone hugging one of these buckets. It is as if no one understands the inverse square law, and that contact readings by themselves are useless in determining exposure. Simply put for every time you double the distance, your radiation exposure goes down to 1/4 of the amount. To put that in other words 400 times the safe level at 0.1 inches is 100 times the safe exposure limit at 0.4 inches, and is 25 times the safe exposure limit at 0.8 inches, does anyone want to continue to do the math for say 2 feet which I suspect might be the closest a member of the public would be allowed to something in an exhibit? This is of course an over simplification of the matter as Uranium primary decay chain is through alpha particle and beta emissions, alpha particle emitters are primarily an inhalation hazard, which should be nearly a non issue with ore in a paint bucket since the alpha radiation can be blocked by something as thin as a sheet of paper, beta particles are not that much stronger so there is a good chance the majority would be blocked by a metal paint can, this leaves the gamma emitters further down the decay chain, which may pose a threat, though without those detailed readings how much of a threat they are is anyone's guess.

and your point is? could you explain this theory again?

[MapleKing]

Originally Posted by rvethereyet

and your point is? could you explain this theory again?

I think the last sentence was about half the paragraph and left me scratching my head as well:

"This is of course an over simplification of the matter as Uranium primary decay chain is through alpha particle and beta emissions, alpha particle emitters are primarily an inhalation hazard, which should be nearly a non issue with ore in a paint bucket since the alpha radiation can be blocked by something as thin as a sheet of paper, beta particles are not that much stronger so there is a good chance the majority would be blocked by a metal paint can, this leaves the gamma emitters further down the decay chain, which may pose a threat, though without those detailed readings how much of a threat they are is anyone's guess."

[mobilemike]

Originally Posted by MapleKing

I think the last sentence was about half the paragraph and left me scratching my head as well:

"This is of course an over simplification of the matter as Uranium primary decay chain is through alpha particle and beta emissions, alpha particle emitters are primarily an inhalation hazard, which should be nearly a non issue with ore in a paint bucket since the alpha radiation can be blocked by something as thin as a sheet of paper, beta particles are not that much stronger so there is a good chance the majority would be blocked by a metal paint can, this leaves the gamma emitters further down the decay chain, which may pose a threat, though without those detailed readings how much of a threat they are is anyone's guess."

What is means is the possibility of anything harmful coming from the bucket and reaching someone standing several feet away is very small if not impossible.

[ajsfla]

Originally Posted by rvethereyet

and your point is? could you explain this theory again?

Ok I used to work for a oilfield testing company and many of our tools used various radiation sources to determine oil content in a formation. We used Cesium 137 CO60 , plutonium ( was replaced in 70s with a different isotope because of concern over plutonium being material that could combined in the wrong hands into a dirty bomb or worse). These "sources" were encapsulated in a pressure vessel since we put them down hole in a hostile environment. Still they emitted radiation when not in a shield. We were trained in radiatipon safety and wore TLD dosimeter badges which recorded our exposure.

The rule of the inverse square means as distance increases the radiation level goes down by the invere square of the distamce. So if you double the distance the radiation goes down to 1/4 of te closer radiation.

So the distances people were away from the "bucket" would make it very very small, comparable to slightly more than a luminous analog watch ( remember those??) Then if the "bucket" had any type of cover most of the alpha particle would be blocked.

We had a radium 226 calibration source which emitted gamma rays and alpha that was enough to perform a calibration of our equipment but DID NOT need any shielding because the exposure was so low. It always was secured but no shield.

I wore a TLD badge every day i worked there for 20 years. I can say all 4 of my grown kids are normal, no webbed feet or extra toes LOL. Quite a few of those years i handled radioactive material on a daily basis and never did i have a badge reading anywhere close to the legal exposure level.

Sorry for the long story but sometimes people sensationalize and blow something out of proportion....

[jimcumminsw]

Do not travel to Chicago IL. and enter Union station or any other large Granite built builds these too emit radiation. My basement also is a potential source for radiation since it sits atop a gravel pit. I have lived with basement in homes in IL. for over 70 years and I am still here, I do not worry.
I even drink "DIET COKE" and other diet drinks since the late 60's and guess what? "I still here" !

[Solo_RV_Guy]

Inverse square law applies to any energy that radiates spherically, or as from a point on a sphere. If you double the distance the apparent energy is 1/4 at that distance.


An example you might be more familiar with is sound. The inverse square law is why sound gets quieter as you move further from the source.



I agree that the original story is more click-bait than substance.

[packnrat]

you want to get radiation burns just go outside in the summer sun anywhere south of the north pole. and get a tan.