NHK—Radiation detected in beef, vegetables

[OKIsItJustMe]

http://www3.nhk.or.jp/daily/english/01_05.html

Radiation detected in beef, vegetables

Radiation exceeding safety standards has been detected in beef from Fukushima and vegetables from Ibaraki, Tochigi and Chiba prefectures.

The health ministry says it detected 510 becquerels per kilogram of radioactive cesium, above than the national limit of 500, in round beef from a cow raised in a village in Fukushima prefecture on Wednesday. The beef has not been shipped.

In Hitachi city, Ibaraki prefecture, 8,300 becquerels, or 4 times above the accepted limit, of radioactive iodine was detected in spinach. Spinach and parsley from other parts of Ibaraki were also found to be contaminated with higher-than-acceptable levels of radiation.

Spinach, shungiku, or garland chrysanthemum, and parsley with radiation exceeding acceptable levels were found in Chiba prefecture.

…

Friday, April 01, 2011 05:09 +0900 (JST)

[AndyTiedye]

1. Hitachi City is Almost 100 Miles South of the Plant

more than halfway to Tokyo, and the prevailing winds should have blown most of the fallout the other way.

This must be a lot worse than they have been saying.

[caraher]

2. The fallout won't be uniform

You'll get some hot spots at large distances. I've watched some of the simulations and while the prevailing winds do mostly blow things out to sea there are some days when the projected plume has been a bit to the southwest.

There are probably some places fairly close that are not badly contaminated and some small areas quite far that have a high concentration of contamination.

[AndyTiedye]

3. and if it keeps spewing radiation for months or years?

[FBaggins]

4. It hasn't been "spewing" for some time.

It's leaking a great deal... but not "spewing".

Even around the plant itself, the radiation levels in the air have fallen significantly... and there isn't much chance of many significant steam releases now that the cores are at a couple tenths of a percent of full power.

The ongoing radiation hazard is mostly in the cleanup and the leaking cooling water.

[AndyTiedye]

5. Then Why are Iodine 131 Levels So High?

Iodine 131 has a fairly short half-life. There shouldn't be so much of it around by now,
yet levels are still quite high. Where is it coming from?
Things aren't quite as "shut down" as they're supposed to be.

[FBaggins]

6. They aren't in most cases

Iodine's half life is around eight days, so there should be about 1/4th as much of the stuff as on day1, but there were multiple days of deposition. So in general (with wild variability) you should expect a few days of rising levels followed by a gentle decline. This is muddled by the fact that weather patterns haven't been constant (nor were releases), so there's tons of variability... and the farther away from the source you go, the longer the delay in the curve.

Things get a little more complicated when we're talking about the ocean though... since that leak is continuing. The Iodine levels in the core may by 1/4th of what they were on day 1... but that's still allows for MUCH higher concentrations in water that's leaking out. Levels influenced by that leakage may continue to go up for some time unless they can identify and manage the leak.

It isn't safe to pick a single spot to watch and say "this is what radiation levels are doing", because we just don't know where the "plume" was on any given day and how that compared to the timing of various releases... but take a look at Tokyo's water supply. Radioiodine levels there are down to about 1/4 of where they were at the peak.