*Not pure, only when ingested as the trace present in normal Potassium.
Intro & the gist
I started out by writing the subject title, and wondered,… Hm… “Wouldn’t that be nice if I had a really well-researched answer to that?” Why IS similarly radioactive Cs-137 somehow considered more Health-hazardous than K-40’s. Is it? It is, right? It bétter be, I just had another bowl of soup with some excellent Potassium-rich Hokkaido kelps in it. (Delicious! +45 CPM goodness ;-) Such a relief…) What I found out about K40 versus Cs137 is this blogpost.
The differences between K-40 and artificial fallout radionuclides like Cs-137, Cs-134, Sr-90, Pu-239, etc are so huge the often-used reference to potassium-rich foods (like bananas) to make scientific-sounding comparisons about fallout dangers (by only looking at radiation dose), and as such making Cesium-137 sound like it’s not different than the radioactive potassium in your spinach, etc… falls apart so easily, it is hard to believe that nuclear experts and supposed investigative reporters still spew that nonsense.
(Unless, of course, they’re under “the nuclear spell” and are doing it intentionally to deceive… but I won’t speculate in that direction in this blogpost. Just the science here.)
The gist is simple: Potassium also has important biological/chemical qualities that make it both an important micronutrient, as well as a cancer-fighting agent; the slew of manmade fission products neither.
That Cesium is somehow benign because some small amount of it may be smaller than the dose from Potassium-40 in the same food is one of many LIES that has long left advocates in favor of nuclear energy (who continue to spout this nonsense) without credibility.
Well… You make up your own mind. I put some facts about Potassium (and its K-40) and Cesium (& Cs-137) side by side here, as usual with information sources included:
3 parts to this blogpost:
Potassium (K, as in ‘Kalium’) is a soft, silver-white metal. An important constituent of soil, it is widely distributed in nature and is present in all plant and animal tissues. Potassium-40 is a naturally occurring radioactive isotope of potassium. (An isotope is a different form of an element that has the same number of protons in the nucleus but a different number of neutrons.) Two stable (non-radioactive) isotopes of potassium exist, potassium-39 and potassium-41. Potassium-39 comprises most (about 93%) of naturally occurring potassium, and potassium-41 accounts for essentially all the rest. Radioactive postassium-40 (K-40) comprises a very small fraction (about 0.012%) of all naturally occurring potassium. K-40, the main source of radioactivity in our bodies, has a half-life of 1.42 billion years.
On SFGate there’s this informative article, by Stephanie Chandler of ‘Demand Media’, “What Is an Acceptable Potassium Level?“. It goes into causes and symptoms of hypo-kalemia (due to potassium deficiency in blood) and hyper-kalemia (excessive potassium in blood), and mentions a recommended intake for a hypothetical ‘average adult’:
“To help keep your potassium at acceptable levels, the Institute of Medicine recommends adults consume 4,700 milligrams of potassium per day.”
The crazy implication of this is that you can search for HEALTHY K-rich foods with your Geiger Counter (as long as radioactive contamination from harmful fallout (cs-137, Sr-90, I-131, Pu-239, etc.) remains absent or at least very low. Given the radiation scare on the US West Coast right now (which I have already admitted I had fallen prey for to as well, albeit with nuance and willingness to change my mind when presented with trustworthy evidence to the contrary), this is almost humorous. ;-) Check it out:
Since it’s really hard to guess Potassium content of food from just looking at it, and labels and websites merely give averages and estimates (proven to miss the mark by a factor 10 or more sometimes), a sensitive Geiger Counter is your best friend:
As regular readers know, to my great surprise and utterly shredding previously held beliefs about long-distance impacts on food quality of Fukushima’s radioactive fallout, I recently discovered that most elevated radioactivity in food, even in scary-hot-appearing Japanese seaweeds, is from naturally occurring Potassium-40. Unless new more serious contamination messes with this trick, you can actually (still!) use your (Medcom Inspector Alert) Geiger Counter in most places to estimate the Potassium-40 activity concentration, and thus the Potassium content, of your food. How about that? (Amazing, not? Make sure to read my disclaimer: I insist you think for yourself too.)
This “Guess Assistance Table” graph is not a precise exact science (some data were not quantifiable within acceptable margins of errors), and many factors could easily mess with this, yet -based on just 9 analyzed samples- some rough estimates may be made:
The image above is from the end of my blogpost admitting having been wrong and sharing all Lab Results DATA of what I thought to be dangerously radiation-contaminated food items. It shows how lab-detected Potassium-40 levels (horizontal axis) correlate (vertical intersections; within a range (somewhat broad due to lack of sample data) that I colored grey) with ‘Added CPMs’ (vertical axis), measured with my Medcom Inspector Alert Geiger Counter. The Gross Beta levels indicated that the correlation here was clearly causal: high K-40 levels were the predominant cause of the measured elevated radioactivity. Actual Fukushima-originated contamination turned out to be near-zero!
So, Question: what is “4,700 milligrams of potassium per day” in terms of daily K40 activity intake levels? Answer (math below): 145.69 Bq of K40. There’s no way around this, all Potassium contains radioactive Potassium-40. We evolved with this.
The math to get from “4.7 grams of K” to “145.60 Bq of K-40” is as follows: All Potassium contains 0.0118% Potassium-40, thus… 4.7 g contains… Easy: 4.7 g of K includes 0.000118 x 4.7 = 0.0005546 g K-40 = 0.0000005546 kg K-40 ; and K40 = 0.0000071 Ci/g (see here) or, in SI units, pure Potassium-40 has a radioactivity of 262,700,000 Bq/kg ; So: 0.0000005546 kg K-40 therefor contains 262,700,000 x 0.0000005546 = 145.69 Bq — Voila.
Thus, the recommended adult dose of 4.7 g Potassium per day means that this amount in food will, by default (unavoidable), add (rounding up) some 150 atomic decays every second (150 Bq) to your body:
“About 89.28% of the time, [K-40] decays to calcium-40 (40Ca) with emission of a beta particle (β−, an electron) with a maximum energy of 1.33 MeV (high energy beta, more even than Cs-137’s beta decay) and an antineutrino. About 10.72% of the time it decays to argon-40 (40Ar) by electron capture, with the emission of a 1.460 MeV gamma ray (almost a quarter of Cs-137 gamma decay energy) and a neutrino. Very rarely (0.001% of the time) it will decay to 40Ar by emitting a positron (β+) and a neutrino.” [Wikipedia K40]
This is ionizing radiation: Radioactivity of high-frequency radiation that has enough energy to remove an electron from (ionize) an atom or molecule. Ionizing radiation has enough energy to damage the DNA in cells, which in turn may lead to cancer. (Source: American Cancer Society).
Before I look at Cesium-137 by itself, Just want to point out that Potassium-40 is not the only naturally occurring radioactive isotope, either; and that other natural factors also contribute to the radiation dose we receive every day.
Potassium-40 as part of natural background radiation:
With 7.1%, Potassium-40 is a significant contributor to the radiation amounts we are surrounded by, and that is part of the natural radioactivity of our body and many of the foods we eat. Far more harmful Radon-222 is the most significant, and is linked to over 20,000 lung cancer deaths in the USA alone. [US EPA claim]
The decay energies of Potassium-40 include high-energy beta and gamma, which just like the beta and gamma in Cesium-137’s decay chain can cause harm to cells. K-40 emits more than double the amount of Beta decay energy compared to Cesium-137’s. Yet, as far as the much more penetrating gamma radiation goes, the average absorbed energy per decay for K-40’s gamma decay energy is only 156 keV, while the average absorbed energy per decay of Cs-137’s gamma decay energy is 563 keV, 3.6 times more than K-40s:
What this decay energies table above does not show is that there are vast differences in the chemical qualities and immense differences in the biological roles of both elements. There is a lot more to Potassium than its inherent radioactive qualities. For one, it’s an essential micronutrient that is under tight homeostatic control, which means that you could only get deficient, but a healthy person couldn’t get too much of it, the excess would be excreted anyhow. (Hyperkalemia is due to a disruption of the potassium homeostasis mechanism, not due to “too much Potassium”).
A closer look at some Potassium’s qualities:
“Some radioactive food is good for you, but not because of its radioactivity.” was another idea for a title for this blogpost. ;-)
In terms of food… the 145.69 Bq K-40 contained in 4.7 g Potassium (calculation above) is basically like eating 2 pounds of bananas per day. (Bananas contain on average of only 150 Bq/kg (Sources vary: 130 Bq/kg here; 150 Bq/kg here, etc.). 1kg is 1000 g. 1 pound is 454 g).
Much better than a banana: take a 100 g package of nutrient-rich kelp, let’s say a clean precious 3,000 Bq/kg K-40 kelp (On a 10 minute CPM test, I’d be looking for an added CPM level of about +45 CPM to +65 CPM, see guess-assistance table. Depending on where you are, that’s at least double background radiation). Such a seaweed package, say 100g, easily found when searching for its elevated natural radioactivity in grocery stores, is plenty for inclusion in a meal for 3 people. It would provide about 100 Bq K-40 per person, thus – by logical extension – providing 2/3rds of all Potassium you need per day. ;-) Add a few veggies, and -tada!- such “naturally radioactive kelp” can be part of a healthy nutritiously balanced diet.
On a side-note, to put it differently: Scare-mongers beware, you may be setting in motion unintended health consequences: if one were to avoid ALL food that makes a Geiger Counter’s measurement go up even the tiniest bit, risk of developing hypokalemia may increase. Its symptoms include fatigue, muscle weakness, abnormal heart rhythms, even paralysis. In contrast, unless you have metabolic health problems, you could eat as much of Potassium-foods as you want, you’d only absorb what you need anyhow.
Interestingly, diarrhea and vomiting, symptoms of radiation sickness, can cause hypokalemia (compounding recovery chances; radiation sickness ALSO causes fatigue, weakness, disorientation, etc.). In addition to the dietary information shared above, I wonder if this may be one of many factors that make seaweeds, including the potassium-rich ones, so helpful for the recovery from radiation sickness. To also quote from “Macrobiotic Diet Saves Lives from Radiation Exposure:
“Seaweeds have been used for generations in the preparation of Japanese cuisine, a regular part of their daily diet. The health benefits that obtained by eating ocean vegetables are reflected in the overall health & wellness of the Japanese & Korean populations. Most notably the lowest rates of cancer, especially reproductive cancers like breast, ovarian & prostate cancer, due in large part to the role that sea-vegetables nourish & detoxify the body.
The power of these ocean vegetables, have long been recognized for centuries, especially in ancient medicines & remedies. After the nuclear bombing of Nagasaki & Hiroshima in 1945, the response from the medical community to those left alive was to eat seaweed to avoid radiation poisoning.
Dr. Tatsuichiro Akizuki was director of the Department of Internal Medicine at St. Francis Hospital in Nagasaki during the bombing. Dr. Akisuki demanded a strict macrobiotic diet of brown rice, miso soup, wakame & other seaweeds, Hokkaido pumpkin and sea salt. He prohibited the consumption of sugar & sweets and as a result saved everyone in the hospital, while many other survivors in the city died from radiation sickness. […]”
The benefits of Potassium as a whole clearly outweigh the potential harm from K40’s ionizing radiation. In fact, it could REDUCE your chances to develop cancer, and may even help to cure it. Here are some quotes (my emphasis) to help explain why that may be so:
“Once taken in, potassium-40 behaves in the body in the same manner as other potassium isotopes. Humans require potassium to sustain biological processes, with most (including potassium-40) being almost completely absorbed upon ingestion, moving quickly from the gastrointestinal tract to the bloodstream. The potassium-40 that enters the bloodstream after ingestion or inhalation is quickly distributed to all organs and tissues. Potassium-40 is eliminated from the body with a biological half-life of 30 days. The potassium content of the body is under strict homeostatic control (in which the amount retained is actively regulated by the body to achieve the normal range required for system functions), and it is not influenced by variations in environmental levels. Hence, the potassium-40 content in the body is constant, with an adult male having about 0.1 microcurie (μCi). Each year, this isotope delivers doses of about 18 millirem (mrem) to the soft tissues of the body and 14 mrem to bone.” [Source: http://hpschapters.org/northcarolina/NSDS/potassium.pdf]
(See my Radiation Units & Conversions page for help with the non-SI units)
The American Cancer Society’s Potassium page notes (my emphasis):
“[…] Some alternative medical practitioners maintain that low levels of potassium in the body may be linked to cancer, heart disease, high blood pressure, osteoporosis, depression, and schizophrenia. Some proponents claim that a diet high in sodium and low in potassium promotes tumor growth by changing the normal pH and water balance in human cells. […] The Food and Nutrition Board of the National Academies of Sciences has set Adequate Intake of potassium at 4.7 grams per day for most adults. No upper limit was set for potassium intake from foods. […] Some studies that observe large groups of people have found that in a number of countries where there are high-potassium diets, cancer rates are lower. In areas where there are low-potassium diets, these studies showed the cancer rates are higher. These types of studies, however, do not prove a direct connection [nor do they disprove lack thereof], because there are many other factors involved. […]“
Comparing diets would take far too much time for this blog post, but from browsing around, it’s clear that diets with sufficient or extra Potassium (more fruits and vegetables) are helpful to maintain a balanced Ph (see Better Nutrition, see also “Gerson Therapy” (includes Potassium to stimulate oxygenation and detoxing), or see this excerpt from the scientific study, “Potassium, sodium, and cancer: a review“:
“[…] Agents known or believed to be carcinogenic decrease the concentration of potassium and increase the concentration of sodium in the cells. Anticarcinogenic agents have the opposite effect. In all cases where we have information on an agent’s carcinogenicity or anticarcinogenicity and on that agent’s effects on cellular potassium and sodium concentrations the above relationships have been found to be true. Dietary carcinogenic agents studied include sodium, cadmium, fat, cholesterol, calories, and alcohol; dietary anticarcinogenic agents include potassium, vitamins A, C, and D, selenium, and fiber. […]“
The benefits of healthy Potassium intake is clearly so strong that they outweigh the effects of its inherent beta/gamma radiation só múch that Potassium actually may help PREVENT cancer. A healthy amount of Potassium is a key part of a balanced diet.
Now let’s have a look how well bananas, brazil nuts, spinach, kelp and other nutritious foods rich in essential potassium compare to Cesium-137, one of the key radioisotopes found in fallout from nuclear accidents like Chernobyl and Fukushima… See how much I should eat of thát…
Caesium-137 or Cesium-137 (Cs-137) is an artificial (man-made) radioactive isotope of the (only mildly toxic) metal cesium. Unlike diet-essential Potassium, which always contains Potassium-40, naturally occurring stable Cesium does not contain Cesium-137. In fact, Cs-137 did not even exist (at all) in nature before the nuclear era. It is formed as one of the more common fission products by the nuclear fission of uranium-235 and other fissionable isotopes in nuclear reactors and nuclear weapons.
Composition of the Human Body – Some perspective: Approximately 96% of body weight consists of only four elements: oxygen, carbon, hydrogen, and nitrogen. Then there’s the essential micronutrients: Calcium, phosphorus, magnesium, sodium, potassium, chlorine, and sulfur are macronutrients or elements the body needs in a significant amount. And there’s trace elements, some of which play a life-supporting function in living organism. Not all elements which are found in the human body in trace quantities play a role in life. Some of these elements are thought to be simple ‘bystander contaminants‘ without function (examples: cesium, titanium), while many others are thought to be active toxins, depending on amount (cadmium, mercury, radioactives).
– Cesium-137, a radioactive ‘bystander contaminant’, is among the most problematic of the short-to-medium-lifetime fission products. It easily moves and spreads in nature due to the high water solubility of cesium’s most common chemical compounds, which are salts.
– A Synergistic for Cesium toxicity (uptake/retention) is Potassium deficiency. To decrease Cesium toxicity (uptake/retention), Potassium supplementation is recommended. (So, eating some of that non-contaminated radioactive (potassium-40 rich) seaweed may help both reduce the uptake of cesium-137, as well as aid in reducing its harmful effects.).
– Cesium toxicity symptoms are fatigue, muscle weakness, palpitations and arrhythmia. Cesium-137, which is radioactive on top of that, may cause or contribute to radiation sickness, including any of the following symptoms: bleeding from the nose, mouth, gums, and rectum; bloody stool; bruising; confusion; dehydration; diarrhea; fainting; fatigue; fever; hair loss; inflammation of exposed areas (redness, tenderness, swelling, bleeding); mouth ulcers; nausea and vomiting; open sores on the skin; skin burns (redness, blistering) ; sloughing of skin; ulcers in the esophagus, stomach or intestines; vomiting blood; weakness; all the way to death. (Doesn’t quite sound like potassium, does it?) Longer periods of exposure to relatively significant levels of Cs-137 contamination, from contaminated sites or nuclear accidents, can result in cancer risks much higher than typical environmental exposures.
Cesium-137 can be taken into the body by eating contaminated food, drinking water, or breathing air. After being taken in, cesium behaves in a manner similar to potassium and distributes uniformly throughout the body.
The strong external gamma radiation associated with its short-lived decay product barium-137m makes external exposure a concern, and shielding is often needed to handle materials containing large concentrations of cesium. While in the body, cesium poses a health hazard from both beta and gamma radiation, and the main health concern is associated with the increased likelihood for inducing cancer.
A look at the decay energies:
Cesium-137 undergoes high-energy beta decay, primarily to an excited nuclear isomer of Barium-137, which in turn undergoes gamma decay with a half-life of about 150 seconds. The energies of both the beta decay of cesium-137 and the subsequent gamma decay of the excited barium 137 are 512 keV and 662 keV, respectively.
PS: If you’re interested in also comparing decay energies and other nuclear details of various important isotopes, which ignore crucially important chemical characteristics and/or biological aspects, see the ANL’s “Radiological and Chemical Fact Sheets to Support Health Risk Analyses for Contaminated Areas“
In addition, Cesium is much more chemically reactive than many of the transition metal fission products. As a group 1 alkaline metal, elemental Cesium is quite electropositive, and is readily oxidized by water, forming highly soluble Cs+. For this reason, elemental Cesium-137 may contaminate large volumes of water during nuclear accidents, which are difficult to contain or process.
[Sources : US National Library of Medicine, Cesium-137: A Deadly Hazard (Stanford University), Health Physics Society, US Environmental Protection Agency, Toxicology Data Network, art dating article, Wikipedia]
Cesium-137 is a carcinogenic man-made unwelcome contaminant, while Potassium-40 is always included in the essential macronutrient Potassium, which plays an important role in metabolic health, reduces cancer risk as part of a balanced diet and even helps reduce the harmful effects of Cesium-137. You absolutely want to avoid inhaling or digesting Cesium-137. The differences are enormous.
Think it was just an oversight that no maximum allowable dose for Potassium-40 has been established? Of course not, K-40 is always present within all Potassium, which is necessary for health. (Because of that, Potassium-40 is not even considered a toxin, either.)
My calculations above show that a healthy intake of 4.7 g Potassium will contain about 150 Bq K-40. Thus, you may want to consume “about 150 Bq of radioactive Potassium-40* per day” to stay healthy (!), perhaps a little more if you suffer from radiation sickness or are at risk for it in a fallout zone (see quotes above). (*Not pure, of course, but always as a result of eating about 4.7 grams of the essential dietary nutrient Potassium (K), which by nature contains some K-40.)
In contrast with no-limit-K40, the maximum allowable dose for Cesium-137 in adult food is 100 Bq/kg in Japan, 1000 Bq/kg in the EU and 1200 Bq/kg in the US:
For fisheries product, the critical limit set by the US FDA for either Cesium-134 or Cesium-137 is 370 Bq/kg.
- Jan. 19, 2014: Independent LAB TEST RESULTS: RadioIsotope Analysis of Hokkaido Kelp and other Samples – (Store-sampled in Japan Nov-Dec 2013)
- January 12, 2014: Caught Nov, 17, 2013, 37 km south of Nuclear Disaster Site: A Black Sea Bream fish with 12,400 Bq/kg of Cs-137
- Janury 9, 2014: Could (natural, normal) radioactive Potassium-40 (K-40) be the main cause of elevated radiation levels in food?
- July 31, 2013: Red Alert – Fukushima-Daiichi NPP Crisis: EXTREME Radioactive Water Leaking into Ground; Unprecedented Radioactive Contamination of Pacific Ocean.
- September 30, 2011: Cesium Deposition Fallout Maps of Fukushima and Chernobyl compared
—– —– —– —— —— —— ——-
ADDED MATERIAL (added after original posting. The below just adds more of the same, plus additional resources to further illustrate this topic:
(added Jan. 26, 2014): Scientific Tunnel Vision? + Additional Evidence of Cesium-137 being far more dangerous than just “2.5 times” the risk from Potassium-40-containing Potassium (which is all natural Potassium)
I received a couple emails suggesting K40 “réally is still causing the harm the effective dose indicates, it’s just that “other factors” hide it” (and a couple variations on that theme.) Yeah, well, not sure how to drive this one home: the main “other factor” is potassium itself, from which K40 can’t be separated. (Is that really so hard to grasp?) It’s included, at some 118 ppm (118 radioactive potassium particles for every million stable potassium particles), always.
Personally, just my viewpoint, I’ve seen a few too many “dose comparisons” that were so taken out of context (out of the context of actual lived reality), that I question the scientific soundness of drawing real-life conclusions from theoretical calculations of “isolated K-40”, a form in which it does not occur in nature (not sure how many times that needs to be repeated, but it is always part of overall Potassium). The calculated effective dose indicates it’s “carcinogenic” (dose K-39 + K-41 (both stable) + dose K-40 = “cancer risk of potassium ingestion” according to NUCLEAR PHYSICISTS. Just the cancer risk of K-40, in isolated form, is, theoretically correct, for sure, but what’s the relevance of that for living beings, whose entire uptake of K40 is not only coming from potassium-containing foods, but whose amount of Potassium (and thus K40) in the body is under strict homeostatic control, and, to top it off, the net health-effect of this potassium in the diet is cancer-fighting, not cancer-causing.
Some technical EPA reports can tell you more about “the risks associated with various isotopes,” but when it comes to radioactivity, they look at just radioactivity, treating nutrition like it’s nuclear science. I find that absurd. I’ve seen the theory: Theoretical cancer risk (danger! danger!) associated with K-40 ingestion is “5.02 x E-9 Sv/Bq”, while for manmade nuclear fallout radioisotope Cs-137, it’s “1.35 E-8 Sv/Bq”, which would have one believe that consumption of the micronutrient Potassium, with its inherent K40, is ‘carcinogenic’, and Cesium-137 is “only 2.5 times more carcinogenic”. That to me is an example of scientific tunnel vision, of the nuclear scientist type. Potassium isn’t carcinogenic. There is no epidemiological evidence of higher consumption of K40 causing more cancers, to the contrary! As already explained above, this is due to the chemical and biological factors, which those silly dose comparisons factor out, oh-how-surprising… making man-made radioisotopes not look as bad.
Epidemiology Caesium-137 / Cesium-137 – There’s been very little study on this. It’s not my intention to make this a reference for Cs-137 cancer evidence studies, but you’re welcome to sign in and comment if you have more to add.
- Unlike Potassium, Cesium-137 is carcinogenic, likely worse even than what the effective dose calculation suggests. Some studies suggest that just deposition of 100,000 Bq/m^2 (with unknown ingestion) may raise cancer incidence by 9 to 10.5 % (SOURCE: Post-Chernobyl Northern Sweden study: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1732641/pdf/v058p01011.pdf)
- See also Germline mutation frequency at human minisatellite loci found to be twice as high in Belarus families, directly correlated with the level of caesium-137 surface contamination. (See: http://www.nature.com/nature/journal/v380/n6576/abs/380683a0.html)
[Except for minor edits, last updated: February 2014]
You might also find interesting observations or helpful tools at these:
- !–> Radiation Units & Conversions
- !–> And some additional key pointers to see through nuclear deceptions in media reporting.
- Nuclear News Links