Milk sample update (1/14/2012)
1/14/2012 (9:40am): A milk sample with a best-by date of 12/29/11 has been tested and the results posted to the milk sample page. Low levels of both Cs-134 and Cs-137 were still detected in the sample.
By integrating all of the milk data we have collected since March 11, we can estimate the total effective dose equivalent (TEDE) one could have received from exposure to fission product isotopes in milk to date. For someone drinking milk at the relatively high rate of one gallon per week, the TEDE could be nearly 1 microsievert, or the total effective dose equivalent for only 12 minutes on an airplane flight or 3.7 hours of the average person's background exposure from natural sources of radiation.
Mark [BRAWM Team Member]
Oh Brawm
I cannot understand how this calculation can be taken to be so accurate given that the conditions are so varied? If the atoms are releasing energy, that must be stored in the tissues and therefore the total energy emitted by a material is known to us. Therefore, the energy emitted cannot be unlimited.
-Bishal from http://techattitude.com
Wow. What a completely
Wow. What a completely incoherent comment.
Milk In SF
Why is the University Nuclear dept, that has done the milk tests comparing it to external radiation of flying in a plane???
Most people who dont know what is in the milk and rely on goverments to tell them or fix the problem will drink this milk and receive (internal radiation) dose of an isotope that will attack organs inside the body.These isotopes inside the body are nothing to casualy compare to external radiation...you should be ashamed of yourselfs...just look to Chernobyl and thyroid problems from internal radiation of only one reactor core explosion,not a unit 3 mox fuel explosion as found at Fukishima.
BRAWM has nothing to be ashamed of.
Why is the University Nuclear dept, that has done the milk tests comparing it to external radiation of flying in a plane???
These isotopes inside the body are nothing to casualy compare to external radiation...you should be ashamed of yourselfs..
=================================
Then you don't know how the calculations are done. When you have an internal emitter, the radioactivity tells you how many radioactive atoms there are. The product of the decay constant for that material and the number of atoms is the rate of radioactivity.
So there are "N" atoms that can decay and release radiation. For each of these atoms, the energy of the radiation is known, and we assume that energy is deposited in the tissues. So there is a known amount of total energy that the radioacitve material can emit. Some think that if you have a radioisotope in you, it emits forever, and the dose is unlimited. That is FALSE.
For the external source like the airplane flight, one can also calculate how much energy is deposited in the tissues.
The comparison is of like quantities - how much energy can an internal radioactive source deposit in you, vis-a-vis how much energy can an external source deposit in you.
BRAWM has NOTHING to be ashamed of.
Accuracy
"For the external source like the airplane flight, one can also calculate how much energy is deposited in the tissues."
How accurate are these calculations/assumptions and how can you compare full-body cosmic radiation doses from an airplane flight with intercellular, point blank irradiation to the cells and tissues concentrated in, on, and around the thyroid (and other target tissues/organs)?
Radiobiologists, radioecologists and environmental scientists across the globe have rejected this false, physicist-perpetuated comparison. Especially scientists whom lived in Europe during the Chernobyl disaster.
The sun is bombarding the Earth at different levels of intensity at/during different times/seasons/conditions/cycles. How can this calculation be generally accurate and relevant given the variability of circumstances?
source:
"The amount of cosmic radiation you are exposed to while flying depends on your altitude and latitude (distance from the Earth’s equator) and solar activity."
http://www.epa.gov/radtown/cosmic.html
Additionally, there are 9 outcomes from the irradiation of a cell:
● No effect.
● Division delay: The cell is delayed from going through division.
● Apoptosis: The cell dies before it can divide or afterwards by fragmentation into smaller bodies, which are taken up by neighbouring cells.
● Reproductive failure: The cell dies when attempting the first or subsequent mitosis.
● Genomic instability: There is a delayed form of reproductive failure as a result of induced genomic instability.
● Mutation: The cell survives but contains a mutation.
● Transformation: The cell survives but the mutation leads to a transformed phenotype and possibly carcinogenesis.
● Bystander effects: An irradiated cell can send signals to neighbouring unirradiated cells and induce genetic damage in them.
● Adaptive responses: The irradiated cell is stimulated to react and become more resistant to subsequent irradiation.
Sources:
HALL, E.J., Radiobiology for the Radiologist, Lippincott, Philadelphia, PA (2000).
NIAS, A.H.W., An Introduction to Radiobiology, Wiley, New York (1998).
STEEL, G.G., Basic Clinical Radiobiology, Arnold, London (2002).
6-7 of these outcomes are the reasons why radiobiologists will tell you and the general public that the more radiation you ingest/inhale/consume, the greater the risk of cancer and/or other negative health effects.
The fauna and flora have evolved to deal with radiopotassium. ALL of these anthropogenic radionuclides are a real problem that needs to be dealt with politically. The nuclear industry needs to make absolutely certain that it's noisy garbage doesn't get 1) out of hand or 2) into the drinking water of millions of Americans. We are waking up and testing their food and water ourselves.
-Concerned UC Alumni
It's called an AVERAGE!!!
The sun is bombarding the Earth at different levels of intensity at/during different times/seasons/conditions/cycles. How can this calculation be generally accurate and relevant given the variability of circumstances?
"The amount of cosmic radiation you are exposed to while flying depends on your altitude and latitude (distance from the Earth’s equator) and solar activity."
=================================
ALL these calculations are averages. For example, when cosmic radiation is cited in background dose, it is an AVERAGE!!!
All the various outcomes due to radiation exposure can happen when the source of the radiation exposure is a man-made radioisotope, or a Nature-made radioisotope. How does the cell know the difference?
The TRUTH of the matter is that it DOES NOT!!!
ANY physicist and any HONEST radiobiologist will tell you that there is NO DIFFERENCE between alphas, betas, gammas of equivalent energy when one is naturally made and one is Man-made.
There are no "natural" gamma photons and "man-made" gamma photons.
There are no "natural" beta electrons and "man-made" beta electrons.
A 1.0 MeV photon is a 1.0 MeV photon is a 1.0 MeV photon.
How can it be otherwise?
DNA repair mechanisms have evolved to repair DNA damage caused by natural radioactivity, and the same DNA repair mechanism work just as well on man-made radioactivity because the cell, nor Man, nor Mother Nature can tell the difference.
internal gamma knives
hey ===============
ur full of old nuke money .....
must make ya feel kinda punny......
so when your family members start dropping dead as their bioaccumulation rates reach 50 Bq/kg with lesions on their organs what will you say......
oh nuker dude.....
Though myself and this person
Though myself and this person fond of using the = sign have had our differences (and I am making an assumption that this is only one person), I have to agree on the argument given here. Radiation is radiation, and there has indeed been a lot of science to figure internal exposure rates for various isotopes. Also, anyone who argues that radiation from K-40 is OK but radiation from Cs-137 is bad should hold the line that radiation from radon ("natural") is OK but radiation from the dreaded Xe-133 ("manmade") released from Fukushima will kill us all.
Of course my point here is that radon ("natural") and it's daughters are estimated to kill 22000 Americans every year. No doubt, some die from K-40 too, but how could you figure that number? We have not evolved to deal with radon, or K-40, but we have evolved to deal with the effects of radiation, so not all get sick and die but some do, and higher levels of exposure equal higher levels of risk. I saw a good quote from Marco Kaltofen recently on the Safecast mailing list, and the gist was that "naturally occurring and safe are not the same". There is no safe, this is about acceptable levels of risk. Of course for me and mine, and you and yours, that level should be zero, but sadly is not.
Also, the chances of people in the US getting tissue levels of 50bq/kg (since the meat tests I had done on free range animals came in under 1 bq/kg.) seem somewhat remote to me. I hope this is true and would like to see what is going on from a measurable POV.
Does anyone out there know how the levels of Cs isotopes in urine relate to the Cs levels in flesh for humans? We could test for this...
BTW, by no means have I joined the dark side. I think nuclear power, and weapons, and materials, are all the road to hell, not so much by their own nature but by the dark side of ours. I am just saying that I think ====== (who may also be WRONG! WRONG! WRONG!) is right on the natural vs artificial radioactivity argument.
BC 1/30/12
Very accurate - well understood physics
How accurate are these calculations/assumptions and how can you compare full-body cosmic radiation doses from an airplane flight with intercellular, point blank irradiation to the cells and tissues concentrated in, on, and around the thyroid (and other target tissues/organs)?
==================================
VERY ACCURATE!!! The physics of radiation deposition is very well understood. It is basically a Coulomb force calculation.
Evidently you have some misunderstanding of radiation energy deposition because of your use of the term "point blank". It's not like the firing of a gun.
The whole body radiation results in a certain degree of radiation dose, that is energy deposited per unit mass for ALL organs of the body. The energy deposited by a radionuclide is the energy deposited per unit mass - but ONLY for the tissue that is within the range of the radiation from the source.
In that sense, the whole body irradiation is WORSE because if the cited doses are equal, the whole body dose deposits just as much energy per unit mass in the tissue near the radionuclide; but it also irradiates the rest of the body with just as much energy per unit mass.
The sources you cite that state the more radiation dose the greater the risk are studies that involve substantial doses. However, research just recently published in the Proceedings of the National Academy of Science from Lawrence Berkeley Lab suggests this may not be the case with very low doses:
http://lowdose.energy.gov/
http://www.examiner.com/science-in-south-bend/dna-repair-centers-fix-low...
“Our data show that at lower doses of ionizing radiation, DNA repair mechanisms work much better than at higher doses,” says Mina Bissell, breast cancer researcher with the Life Sciences Division. “This non-linear DNA damage response casts doubt on the general assumption that any amount of ionizing radiation is harmful and additive.”
Goddards journal completely discredits your referenced study .
http://www.google.com/url?sa=t&rct=j&q=goddards%20journal%20on%20low%20d...
And I mean completely not "may"mabye or might...
Goddard vs National Academy of Science.
The Lawrence Berkeley Lab study was published in the Proceedings of the National Academy of Science.
That's one hell of a lot more prestigious than Goddard.
I'll go with the National Academy over Goddard any day of the week.
Study of low dose response in humans not in a petri dish
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3075914/
Diagnostic X-ray examinations and increased chromosome translocations: evidence from three studies
Bhatti et al
Controversy regarding potential health risks from increased use of medical diagnostic radiologic examinations has come to public attention. We evaluated whether chromosome damage, specifically translocations, which are a potentially intermediate biomarker for cancer risk, was increased after exposure to diagnostic X-rays, with particular interest in the ionizing radiation dose–response below the level of approximately 50 mGy
???
Can you back up this statement with a study or paper?
"The fauna and flora have evolved to deal with radiopotassium."
BC 1/29/12
Cs 137, 134 and K 40
It is well documented that most organisms maintain a steady concentration of K40 whereas Cs 137, 134, when present in the environment INCREASE IN CONCENTRATION in most organisms. This is tendency to bioaccumulate, and thence biomagnify, is a biochemical property of Cs.
The end result, increases and accumulations spanning decades in long-lived organisms, is what condemns the young and child-bearing to horrible increases in all manner of health problems many of which appear as genetic problems that continue for indefinite generations or problems identified as the health issues associated with old age - premature aging and death.
re:???
Asimov, I. “The Radioactivity of the Human Body.” Journal of Chemical Education, February 1955.
It was one of the last things he wrote.
If you do not have access to the article, let me know.
?????
Asimov, I. “The Radioactivity of the Human Body.” Journal of Chemical Education, February 1955.
It was one of the last things he wrote.
============================
Asimove didn't die until 1992; and he wrote LOTS after 1955!!!
GEESH!!!
Thanks much Mark and
Thanks much Mark and BRAWM.
Very interesting how levels have pretty much plateaued out. It is a for sure deal that the cows in California are eating hay at this time of the year (and in fact may have been as far back as June or July from what I hear). I would expect that once that hay is exhausted and the spring '12 hay and new grass comes into play that the levels will decline finally to ND.
BC 1/14/12
Over EPA mcl limit? Care to comment mark
Over EPA limit: Cesium levels in San Francisco area milk now higher than 6 months ago
http://enenews.com/over-epa-limit-cesium-levels-in-san-francisco-area-mi...
Pasteurized, Homogenized Milk from the San Francisco Bay Area with Best By Date of 12/29/2011
Cs-134: 0.068 Becquerels/liter (Bq/l) ±0.011 [MDA=0.044]
Cs-137: 0.075 Bq/l ±0.015 [MDA=0.052]
Total cesium is .143 Bq/l, or 3.87 picocuries/l (pCi/l) (1 Bq = 27.1 pCi).
The EPA Maximum Contaminant Level for radioactive cesium in milk is 3 pCi/l:
“EPA lumps these gamma and beta emitters together under one collective MCL [Maximum Contaminant Level], so if you’re seeing cesium-137 in your milk or water, the MCL is 3.0 picocuries per liter; if you’re seeing iodine-131, the MCL is 3.0; if you’re seeing cesium-137 and iodine-131, the MCL is still 3.0.” -Forbes.com
Current levels are about 40% higher than what was detected 6 months ago:
Pasteurized, Homogenized Milk from the San Francisco Bay Area with Best By Date of 8/22/2011
Not over EPA limits for drinking water
The 3 pCi/L number is not the EPA MCL for Cesium-134 and 137. Their limits are higher: 80 pCi/L and 200 pCi/L (3.0 Bq/L and 7.4 Bq/L), respectively. Please see this EPA document for isotope-specific drinking water MCLs. Also note that these limits are drinking water limits, not milk limits.
This issue has come up before on the forum — please see my comment from back in October for some more details.
Mark [BRAWM Team Member]
Milk is swallowed...this is
Milk is swallowed...this is called internal radiation not external...these comparisons to airplane flights and background must stop.You swallow these isotopes and they will kill cells inside the body.
Internal External
It would help if they quoted the actual measurements and explained how they do the comparisons. External radiation dose is measured in Sieverts per unit time so if you know the time you know thw total dose. For internal radiation it is measured in Becquerels which means disintegrations per second. To calculate the dose in Sieverts there is a conversion factor called the committed effective dose conversion coefficient which is different for each nuclide. It takes into account the type of radiation and how long the nuclide stays in the body to give the dose you would get over your lifetime from ingesting a given amount of the substance. Provided this has been done properly then you can compare internal and external radiation. Unfortunately they do not quote the actual measurements of their methodolgy which is not very scientific.
Two more points:
A worse thing is that they seem to be only considering cesium. Where there is cesium there is strontium 90 which is far more dangerous but is almost never measured because it is a pure beta emitter and impossible to detect with a geiger counter.
The levels in milk measured in the USA are small and the individual risk is low. But even a small risk to tens of millions of people can still mean that hundreds of thousands might die as a direct result. Individually there can never be any proof though so the people responsible who know this and do nothing will always go unpunished.
Not Correct!
It would help if they quoted the actual measurements and explained how they do the comparisons. External radiation dose is measured in Sieverts per unit time so if you know the time you know thw total dose. For internal radiation it is measured in Becquerels which means disintegrations per second.
==============================
The above is not correct. Activity or radioactivity which is the rate that a radioisotope decays is measured in Becquerels = 1 decay / sec. Contrary to the above, internal "dose" is NOT measured in Becquerels. Activity in Becquerels just tells one the rate at which the radioisotope is decaying and NOT the amount of energy deposited nor any metric of the damage done.
Dose which is the amount of energy per unit mass deposited by the radiation is measured in "rads" or the SI unit is the "Gray" for BOTH external and internal doses. To calculate the dose, one not only has to know the source of the radiation such as a radioisotope, but also what the radiation type is, alpha, beta, gamma; and how that radiation transports and deposits energy in the surrounding material. It is a non-trivial calculation.
Dose Equivalent which is a measure of how much biological damage is done is the dose multiplied by a factor that gives the damage per unit dose. Dose Equilavent is measured in "rems" or the SI unit is the "Sievert".
The above poster is also in ERROR about Geiger Counters not being able to detect beta particles. Geiger Counters can detect alphas, betas, and gammas; and hence DO detect the beta emissions of Sr-90.
The limitation for the Geiger counter is that its signal does not discriminate by energy. If any ionizing radiation enters the Geiger-Muller tube, it triggers a complete "breakdown" and discharge of the charge in the tube. The electronics turns off and resets the tube. However, the signal from the GM doesn't tell you the energy, and hence one can't do spectroscopy with the GM tube. One knows there is radiation there, but not which isotope is producing it. Geiger counters are good "survey" instruments.
BRAWM uses solid state detectors which can do spectroscopy, and hence they can both detect and identify the sources of radiation in their samples.
Look at the ENERGY
Look at where the ENERGY goes. That's what does the damage.
Whether the source of the energy is an internal radioisotope, or an external source; the ENERGY gets deposited in internal tissues. That's what "dose" is - how much energy is deposited per unit mass of tissue.
So if you track where the energy goes, and how much is deposited; it really doesn't matter whether it originates inside your body, or from outside your body. As long as the calculation is done right, taking into account all attenuations and depositions of energy; the comparison of dose or energy deposited is a comparison of like quantities. It's still an "apples to apples" comparison.
BRAWM members have discussed this before.
I don't want to downplay the
I don't want to downplay the accident or the fallout, but will point out this simple fact (which Mark and others have pointed out many times already) - internal radiation is nothing new. A portion of the radiation that you have been exposed to from day one is internal and completely naturally occurring. Look at the milk sample page, up top, and you will notice that every liter of milk has approximately 50bq/l of K40 activity. That means that there is enough K40 in a liter of milk to irradiate your cells at 50 disintegrations per second for as long as that K40 is in your body (and there is always a good deal of it in your body, potassium is vital to life). If we round up the combined Cs activity in recent milk samples tested by BRAWM it's close to 0.4bq/l, so there's about 125 times as much K40 activity as there is Cs activity.
BTW, even that K40 radiation carries a risk. It is just that it is very small, and that most of us never thought about it until quite recently.
BC 1/16/12
"Nature"
The Cesium is a Man Made Isotope, Yes?
Made by diging up the earths bones and combining them, and setting them on fire...to make steam, to power Xboxes.
Unlike K40, Right?
that is why it is Okay to have k40, and not C137, C134, I131, and F'n Plutonium???!!!
This is pure ignorance or stupidity.
UnNatural.
See post above
See post above submitted at Mon, 2012-01-30 20:23.
This "some radioisotopes are natural and others are man-made" is a bunch of NONSENSE!
There are no "natural" photons and "artificial" photons; there are just photons.
good point
Thank you