Food chain updates 5/14
5/14 (6:25pm): Our food chain samples have been updated with new samples of topsoil, grass, wild mushrooms, spinach, kale, and strawberries.
Kale on 4/28 had the first detectable amounts of Cs-134 and Cs-137 since a sample on 4/7. Strawberries continue to show levels of Cs-134 and Cs-137.
Although I-131 was still found in the soil, it was not detected in any of the new grass or food measurements.
Mark [BRAWM Team Member]
Thank you so much...
for publishing your results!!
What again is the significance of the appearance of I-132 in the topsoil?
The grass sample, has the smallest mass yet of the grass that has been tested. So the Ce-137 in that smaller sample increased over the larger sample tested previous. I think the natural inclination might be to multiply that amount by 2.5 to compare the same mass size with same mass size. Would this be an incorrect thing to do?
I missed. That
Thanks for pointing that grass sample size out LT .hope u get an answer.
The I-132 number was a
The I-132 number was a mistake, and I have corrected it. We've been running samples for longer times, and there is a very weak background line coincidentally at the same location as the main I-132 line. Actinium-228 is the naturally-occurring isotope that does this. I-132 is a decay product of Te-132, and it has such a short half-life (2 hours) that it will not be present unless Te-132 is also present. But Te-132 has long since decayed away.
The masses of the samples have already been normalized, so the activities are presented in Becquerels per kilogram. Thus the numbers should be compared as "apples to apples" without any additional math.
Mark [BRAWM Team Member]
Thanks....
I remembered something about I-132 occurring with something else, but even that over-states my knowledge :-)
Okay, I can understand that if the units are normalized, then you are comparing things of the same size/rate. Which leads me to another question, which I'm not sure makes much sense, but, if you take a larger sample size, do you get a better chance of getting a more accurate measurement than if you take a smaller sample size?
Yes, in general a larger
Yes, in general a larger sample size helps get a better reading.
Technically, though, a large sample could be so thick that it would be "self-attenuating" at low gamma-ray energies. This means that it would be thick enough to stop the gamma-rays coming from inside it, and you would no longer get the benefit of having a large sample. We're not too close to this limit for the gamma-ray lines we are looking at though.
In the case of the last grass sample, it was smaller than the previous one because that was all we could get from the yard the samples are coming from. We tried to compensate for the smaller size by counting it for longer in our detector (48,000 seconds as opposed to the previous 33,000 seconds).
Mark [BRAWM Team Member]
thanks
Thanks Mark, I appreciate the answer!
Strawberries vs Spinach
Mark,
Any opinion why Strawberries show Cesium but Spinach does not? I can't understand this as Spinach has such larger leaves vs Strawberries?
Thank you Laura
I sometimes wonder...
...if we are looking for reasons when there really are none. That is, if some of this just has a degree of randomness to it.
Having said that, though, I wonder if, in general, root vegetables would accumulate more of anything that might be in the ground than things like leafy greens?
It's in Bq/Kg already, so
It's in Bq/Kg already, so the result should be size independent.
Ty for. Data
Was hoping to see cesium on the decline ,no such luck not the best of news though looks like no dramatic increase in cesium either. awesome testing keep it up!
Your team deserves a science award or national recognition.thanks guys and girls too if there's any on team.
decline of cesium...
or should I say lack of decline...
I was listening to a previous press conference by the Physicians for Social Responsibility (or something like that), and the speaker noted that near Chernobyl, the Cesium was not decaying as predicted, and they really didn't know why. I guess every time there is such an accident, it really is an experiment on some level, since there don't seem to be "rules" that are always obeyed.
My guess is that it would
My guess is that it would have a lot to do with soil composition, rain, heating of the ground, turnover, airation, additives etc.
It seems like a pretty complex problem, actually.
decline in cesium
or should I say lack of decline...
I was listening to a previous press conference by the Physicians for Social Responsibility (or something like that), and the speaker noted that near Chernobyl, the Cesium was not decaying as predicted, and they really didn't know why. I guess every time there is such an accident, it really is an experiment on some level, since there don't seem to be "rules" that are always obeyed.
.?
Would u say iodine in soil is just old decay or in fact new depositions?