Question to the physics/chemistry/medicine/etc. enthusiasts out there...

[janosik]

What would be the implications of pumping 1000s of tons of radioactive water with strontium-90 and the likes at Fukushima on the safety scuba diving 4000 miles away in Hawaii? Some claim that radioactive waste will remain close to the surface, and will disperse less than the official sources would make us believe. I would be interested in any facts and informed opinions on this matter, see also my post on the regional forum: http://www.scubaboard.com/forums/hawaii-ohana/421537-safety-diving-hawaii-post-fukushima.html

[SnorkelLA]

Let's do the math. You have the I don't know how many millions of gallons of water between Hawaii and Fukushima, then any currents moving between the two that could carry it. Depending on the potency of the radiation of whatever was in that water. Then you have how much they dumped. Then you have to factor in the half-life of radiation (a few hundred years or so).

My honest opinion is that the density of water (the density of materials plays a pivotal role in how radiation protected something is), and especially in the volume between the two points should be more than enough for safety. speaking in theory, even if the radiation MADE it halfway between, the half life (how long it takes to radioactively decompose) could be long enough for it to move all the way.

But I've been leading you on. Even if RADIATION did make it all the way, it would almost certainly reach it in such low trace amounts that it would make it even difficult to detect.

Hope this helped :)

[irishsquid]

You'll probably get more radiation from the sun on the way to the dive site.

[rongoodman]

The solution to pollution is dilution. That's a lot of dilution.

[knotical]

Here’s an article:
New Data Show Fukushima Radiation Moved Rapidly Out Into Pacific Ocean (http://www.voanews.com/content/new-data-show-fukushima-radiation-moved-rapidly-out-into-pacific-ocean-145813175/180228.html)
and the report on a nearly year-old study it references:
Fukushima-derived radionuclides in the ocean and biota off Japan (http://www.pnas.org/content/109/16/5984.full?sid=69d03e20-115f-4a71-a5c0-911cbb60cd8e)

Haven’t found any recent studies, only several articles about predictive simulations with a range of degrees of concern engendered perhaps by the political leanings of the authors.

The answer appears to be that no one knows. But nothing I’ve read yet will stop me from enjoying the water. I suspect the concentrations of contaminants have dramatically decreased.

[KD8NPB]

Some claim that radioactive waste will remain close to the surface

That would be tough, considering that radioactive particulate (non-gaseous) is usually comprised of the heaviest elements known to man.

They're at the bottom of the ocean by now. The tritium that was released has combined with the atmosphere to help make up that "1% trace gasses" in your compressed air fill. :D

I'm a 2nd generation nuke geek. My father is NRC.

[janosik]

Thanks for the responses. Re: dilution and sinking due to higher mass, this is what I was thinking until I read some number of articles about animals with patchy hair loss and skin lesions washing up in Alaska and possibly linked to radiation poisoning. Hypothetically, might it be possible that much of this stuff is traveling with ocean currents, trapped in some thin bio-film or whatever other substance on the surface, which might allow it to cover larger distances without sinking. While the surface of the ocean is large, it also seems to be the case that for whatever reason, most of the pollution is dragged with the ocean currents to places like Hawaii rather than spreading uniformly at random. Apparently, even motorcycles of Japan origin have been found washing up on the west coast, perfectly undiluted. I am not sure what to think about it.

[phuonguyen]

Well the radiation probably isn't enough to cause any significant mutations within the cells. At the most it'd be like getting your finger xrayed which is like being in the sun for a month or so.

Sure, there was alot of output from the initial incident, but like the posts above me, it is radiation from a heavy source (so the source will be removed by sinking to the bottom of the ocean), it's been over a year since the incident and it's really far away from the original source.

There's really only a few ways to reduce radiation exposure, and that's pretty much shielding and distance (inverse square rule). The amount of water between the source at the bottom of the ocean to the dive sites, will remove the radiation rather effectively. And effectively, the distance between the source of the radiation and the dive site will reduce the potency of the radiation (inverse square rule), so the further you are from the source the less of an effect :)

[Centrals]

There must be tons of information on the aftermath of Hiroshima and Nagasaki. Unless they are still classified.

[altaskier]

That would be tough, considering that radioactive particulate (non-gaseous) is usually comprised of the heaviest elements known to man.

They're at the bottom of the ocean by now. The tritium that was released has combined with the atmosphere to help make up that "1% trace gasses" in your compressed air fill. :D

I'm a 2nd generation nuke geek. My father is NRC.
There's something called Reynold's number that describes the scaling between laminar and turbulent fluid flow. It explains why dust doesn't fall to the ground as quickly as baseballs do, and why small particles can remain suspended in the water column for a very long time. This is also why planktonic critters stop moving in water the moment they stop swimming, as you can readily see under a microscope. So just because you have heavy elements in a particle, they don't automatically sink. The real story is more complicated than this answer would imply.

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There must be tons of information on the aftermath of Hiroshima and Nagasaki. Unless they are still classified.
There's the classic book "The Effects of Nuclear Weapons" by Glasstone et al, originally published by the Atomic Energy Commission in 1950 (I have the 1977 edition). Absolutely not classified. There are also the series of Biological Effects of Ionizing Radiation or BEIR reports published by the National Academy of Sciences, and the Hiroshima and Nagasaki populations continue to provide our best information on long-term cancer risks from ionizing radiation.

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Well the radiation probably isn't enough to cause any significant mutations within the cells. At the most it'd be like getting your finger xrayed which is like being in the sun for a month or so.
There's a fundamental difference between ionizing and non-ionizing radiation: whether the photons reach the 3-20 electron-Volt energy (or 400-60 nm wavelength) threshold needed to cause changes in chemical bonds. Ultraviolet light which causes sunburn just starts to reach into this range, but it is stopped in the outer layer of the skin so it won't lead to any radiation damage on internal tissues and organs. X rays, certain types (but not all) of emissions from radioactive particles, penetrate much deeper into tissue (it's why you can see through someone's body with X rays) and lead to ionizing radiation damage in internal tissues and organs. We can't equate getting X rays with being in the sun.

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Here's one informative article (http://www.pnas.org/content/109/16/5984.full.pdf+html). The abstract summarizes the results, and concludes "We address risks to public health and marine biota by showing that though Cs isotopes are elevated 10–1,000× over prior levels in waters off Japan, radiation risks due to these radionuclides are below those generally considered harmful to marine animals and human consumers, and even below those from naturally occurring radionuclides." In other words, dilution is the solution, as others have said.