Soil and strawberry update (5/25)
5/25 (9:48pm): The food chain samples have been updated with one new topsoil measurement (5/18) and one new strawberry measurement (5/19). The levels of all isotopes have significantly decreased in both samples. Iodine-131 is still present in the soil but it is now just above our minimum detectable level.
Mark [BRAWM Team Member]
Thank you BRAWM!! Very
Thank you BRAWM!! Very encouraging to see these results. I'm also hoping to see new leafy green numbers some time soon. Anything in the works?
We're currently counting a
We're currently counting a kale sample; should be done tomorrow.
Mark [BRAWM Team Member]
Would like to see eggs and root vegetables
Thank you for all your hard work! You are the only source out there providing people with information so they can make decisions regarding their health. I would like to see eggs and root vegetables tested if possible. Thanks again for all you are doing!
nice to see....
that these look like they are more of a drop than a bit of a dip.
Now....if they can keep their radiation over there contained (ha!), hopefully it will keep declining.
Is the topsoil taken at the same place as the grass that is tested? I'm assuming that you go back and sample from the same spot each time?
Fabulous work all the way 'round.Tryin' to rap head around Bq/Kg
Too tired right now to artivulate this well but I have a few questions and a request for some interpretation by BRAWM of what you all think this means.
1. It seems to me that based on air and rain samples that there is little new in the way of deposits of radiocesium but that dry deposits may be ongoing a little and may even be creeping up a little based on soil samples. In other words, I would expect cesium 134 to drop off much quicker due to its much chorter half life so do you think we are seeing new deposits or is it just that the cesium in the soil is not going away or dispersing or getting washed out much?\
2. If I am correct (and please correct me if this is totally wrong, just trying to remember what I have looked up over and over again) a Bq is essentially one decay per second so in a Kilogram of soil does that mean, if there is .10 bq/kg that in that whole kilogram there is a total discharge or decay of 1 decay every 10 seconds?
3. and does the decay or radiation "ray" or particle "disperse" equally in that soil or strawberry or does it get absorbed and/or do the radioactive elements (say, cesium 137) disperse equally throughout the soil more or less or is it possible, say, for one section of the soil to have some while others do not (same with plants from the same field) or are you assuming, more or less, that there is equal distribution? THEN, is it equal distribution of the Becquerels or of the from the radionuclide or of the cesium?
4. Finally = how far do these particles of radiation travel when the decay occurs. In other words does the radiation from the decay of potassium 40 travel farther or less far than, say, cesium 134 or iodine 131 (do the radionuclides have DIFFERENT "strengths" in other words. I am still trying to grasp the gamma and beta and alpha distinctions which were somewhat explained minimally in the banana dose thingie I posted BUT do ALL beta emitters act the same in terms of the power or energy and distance the particles (if that is what they are called) travel and would the MEDIUM they are in affect this (soil vs milk vs water vs a strawberry a cell vs a liver vs a thyroid, etc) significantly?
You might guess where I am going with this and what I am wondering: Cesium's behavior in the body is different than potassium and where it aggregates may be different and have a different impact on the surrounding cells than the potassium. Cesium apparently gets stored in muscle and permeates the whole body and potassium is in the intercellular fluid, I think. Does this make any difference in how the decay impacts local cells and tissue and the medium it is in (liquid vs solid, for example).
I am tired but would REALLY hope someone can address these kind of technical questions in layperson's language. Cesium by itself appears to be toxic whereas potassium is an essential element for our bodies but IF their radionculide decay products are impacted by their location in the body and or their own "strength" to penetrate other cells etc or by the "power" of their emissions of gamma rays etc, then the decay prosucts from the radiocesium MAY be more harmful than the potassium 40. That is why I ask these simple questions so I can try to wrap my head around the whole batch of issues.
Thanks again. RESULTS are always excellent to have and are HISTORICALLY important.
Hi Bill, to answer your
Hi Bill, to answer your questions:
1. As posted below, the half-life of Cs-134 is indeed 2 years. We expect the decline to be caused mainly by washout from rain and dispersion in the environment.
2. You're correct; .10Bq/kg would mean one decay per 10 sec in the whole kg.
3. Because the deposition comes from the rain and air (mostly rain here in the US), we would assume that the top of the soil has the highest activity, getting lower and lower as you go deeper. However, there is a distinction between the radionuclide (like cesium or potassium, the atom that emits the radioactivity) and the radiation it emits (alpha, beta, or gamma). The cesium is what gets deposited in the dirt, but the radiation (the stuff we can measure, and the stuff that could cause health concerns if there were enough of it) travels various distances and then stops, leading to your next question...
4. This is a great question, by the way, one that is central to figuring out dose. Alpha particles can't even make it through air. If they're outside your body, they likely won't even touch you. Beta particles can travel further, but are stopped by plastic, a thin piece of metal, or your skin. This is why a few plant workers at Fukushima got burns wading through highly contaminated water -- the beta radiation deposited all its energy in their skin. Gamma rays travel much further, and how far they can go depends on their energy. K-40 emits a higher energy gamma, so it travels further than the gamma from Cs-137 and the other isotopes we've measured, but all of them could go through your body. I like this image on Wikipedia, too, as an illustration.
In general, all beta particles will deposit all their energy in a pretty small area if they are surrounded by some decently thick material, such as soil or the human body.
Thanks for the questions!
Tim [BRAWM Team Member]
"I would expect cesium 134
"I would expect cesium 134 to drop off much quicker due to its much chorter half life"
Cesium-134 half-life is around 2 years. Try at least to check the basics before establishing any theories.
Come now, there is no call
Come now, there is no call to be rude.
Nastiness for its own sake
You know, radioactive decay doesn't happen all of a sudden -- it's not a sharp drop off a mathematical cliff into oblivion, it's a gentle decline sloping gradually toward zero. Decay happens ALL THE TIME, so, actually, you WILL find that Cs-134 is decaying "faster" than Cs-137 -- assuming that the vast majoriy of these radionuclides were released at or near the beginning of this ongoing nuclear event, more than two months ago, then the INITIAL environmental levels of radioactive -134 have ALREADY declined by nearly 9.3%! (By contrast, cesium-137, with its FAR longer half-life, has diminished by a barely perceptible 0.635% over the past ten weeks.)
Of course, nothing's happened to the atoms, themselves; nothing in the natural world simply "goes away" or ceases to exist. We're speaking in terms of radiation, is all, here.)
But -- I think we can agree that the previous poster wasn't COMPLETELY wrong, and if the better-informed among us here are serious about spreading knowledge, as some often contend, maybe we ought to be a touch more accomodating of common mistakes, forgiving of benign ignorance, and encouraging of those who are only, like all of us, seeking answers in these challenging times.
...Just a thought.
Rick Cromack.
Allen, Texas
"assuming that the vast
"assuming that the vast majoriy of these radionuclides were released at or near the beginning of this ongoing nuclear event, more than two months ago, then the INITIAL environmental levels of radioactive -134 have ALREADY declined by nearly 9.3%!"
Wait, how do you get to that 9.3% decline? And even if you are right, how would that be inconsistent with the levels of Cesium 134 and Cesium 137 detected?
About rudeness. I find extremely rude that some are posting extensive paragraphs "proving" their theories only to find out that they haven't even tried to read the wikipedia article on the isotopes of cesium (or the collection date of the samples, in your case).
If anyone, like me, lacks the minimum expertise on the field, the thing to do is to be humble, assume your ignorance and challenge the experts asking questions and going to the point, not writing whole dissertations that the rest of posters have to endure to find out they are based on nothing.
You're right...
My estimates for the decay, after ten weeks, of Cs-134 and Cs-137 were, inaccurately, DOUBLE what their true values should be. The radioactivity of Cs-134 released by Fukushima by March 18, 2011 has declined by about 4.65% to date, I think; Cs-137 has barely dissipated at all. Sorry for the mistaken values.
As for slogging through long "dissertations", fair enough. Don't read 'em.
Rick Cromack.
Allen, Texas
:)
:)
Thank you!! So nice to see
Thank you!! So nice to see the numbers go down. Please keep monitoring air!!! We are so in the dark about what is really being released over there. Thanks once again, you guys are great.
sampling data and analysis
Thanks for devoting much valuable time to this effort. I have also greatly increased both my knowledge and my understanding of what these data mean.