Radiation in the water in Japan

As I’m sure many of you have read or heard recently, the levels of radioactive iodine are a bit high in some parts of Japan, and at one time the Japanese government was advising parents not to let their children drink the water.  Now, I have to stress that this is only in a part of Japan, not the whole of Japan, and it was only for a day or two.  So, safe for adults to drink, not safe for children.  When I say safe for adults, I mean safe for adults unless they decide to drink it continuously for a year, or so I remember hearing somewhere.

For people worried about radioactive water, it’s not the water that’s radioactive, rather it’s particulates, minerals or elements in the water that make it radioactive.  In this particular case it’s a variant of iodine, or isotope of iodine to be more accurate.

Iodine is a naturally occurring element and can be found in everything from mangos to fish, and is usually nothing to worry about except when absorbed in massive quantities – an extremely unlikely occurrence unless you take iodine tablets, which themselves would be thousands of times higher in concentration than a whole mango would be, or unless you already have a sensitivity to iodine.

The radioactive isotope of iodine (131I) that’s in the water has a half-life of a little over eight days.  This means that after a period of eight days, the radioactive iodine that’s currently floating around in the tap water of parts of Japan will no longer be harmful.  So if it’s in your body, eight day’s and it’s nothing to worry about any more.  Same if you bottled the water and kept it for eight days.  Although if you did that, I’d recommend boiling it before consumption to kill off the bacteria.  I read someone say it was 30 days on a chat forum somewhere.  Not sure where that person got their number from.

The British Embassy here in Japan, and I have been told the US as well, has been handing out iodine tablets to their citizens in the Tokyo and affected areas.  Why and how does it work, you may ask yourselves.  Well, iodine likes to settle itself in the thyroid, which is a bit of a sponge for iodine.  The idea is that by taking the iodine tablets, you would saturate the thyroid with regular, harmless iodine, and there would be no room left for the more dangerous, radioactive iodine to be taken in (like trying to add water to a sponge that’s already been soaked in water).

So, what have we learnt?  Firstly, it’s not the water itself that’s radioactive, it’s the stuff in the water.  Secondly, depending on the concentrations of the radioactive iodine, it can be harmful to adults and/or children.  And thirdly, it’s no longer harmfully radiative after eight days.

Does this mean eating a lot of iodine rich food will help saturate my thyroid?  No, I don’t think so.  You would need a lot of iodine to fully saturate the thyroid, or a lot of mangos and a lot of time on the toilet.

If you want to reduce your intake of the radioactive iodine, you could get yourself a water filter with activated carbon (that’s fancy talk for charcoal that’s in itty bitty pieces) in it to help filter out some of the radioactive iodine, go out and by bottled water, or bottle the tap water and wait eight days before you used it.  I’ve been using a water filter (not the same on, mind) for years.

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One Response to Radiation in the water in Japan

  1. Sjors says:

    Hi DJ,

    I had been following the news about the radiation of 131-I. You are right about the danger of radio active Iodine. With a half life of 8 days, the danger is only present for a short time. I’m not telling there is no risk, but the levels are just slightly higher than allowed, it might drop to safe levels in a few days.

    You can always get that strange carbonated red grape juice from the vending machine near your house, if you don’t trust the water. Though, the artificial flavoring and colors might also not be too good for your health (^o^)



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