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Over the weekend, I wrote two diaries on the isotopes of concern to scientists and the public in the event of a possible release of radioactive material from a nuclear power plant (part 1, on iodine-131; part 2, on cesium-137 and strontium-90).

Now, I want to turn to those various units of radiation you've been hearing about: rads, rems, and so on.

As I mentioned in part 1, nuclear fission occurs when the nucleus of an atom is bombarded with other particles; in a nuclear reactor, those particles are neutrons.

When the fission occurs, at least some of the resulting smaller nuclei are themselves radioactive, and capable of decaying spontaneously; as those two earlier diaries noted, uranium, with a mass of 238, produces atoms such as iodine-131 and strontium-90. While there are several ways this can happen, the key thing to note is that radioactive decay does not produce these large particles. Instead, it generally produces one of three other types of radiation:

1. Alpha particles, which are bits of the nucleus containing two protons and two neutrons (in other words, a helium nucleus).
2. Beta particles, which are either negatively-charged electrons or their positively-charged antiparticles, positrons.
3. Gamma radiation, which are photons that carry energy. Of the three forms of radiation, gamma rays are the ones that carry the most energy.

The most basic way of measuring radiation is to simply measure the number of particles released; in other words, to count the number of atoms that disintegrate. There are two units used for this: the becquerel, which is very simply one disintegrating atom per second; and the curie (named after Marie and Pierre Curie), which is about 3.7 x 10^10 (that is, 37 billion) disintegrations per second. [If you're wondering where that number comes from, it's approximately the number of disintegrations per second in one gram of radium-226, an isotope discovered by the Curies.]

Of course, from a practical standpoint of measuring exposure, this isn't particularly useful; as you may have heard already, not all radiation is created the same. What's more important is the total amount of energy carried by that radiation, and how concentrated it is. [Here's an analogy: saying that an acre of land contains a "ton of trash" could mean that you have 2,000 pounds of various debris spread about, or one junked car right in the middle of an otherwise clean field.]

Without going into the technical details, we can determine the basic methods by which radioactive isotopes decay, and the exact amounts of energy that are associated with those methods of decay. [If people really want to know the gory details, I can present it separately.] We can then figure out the amount of energy that human tissue would be exposed to, and based on that calculate the radiation absorbed dose, or rad level. [For the record, there's another unit, the gray that corresponds to 100 rads, or 1 joule per kilogram of tissue.]

One rad corresponds to an absorbed dose of 0.01 joules per kilogram of tissue. To give you an idea of how "small" this energy is, a Big Mac contains about 2 million joules of energy. The reason why these relatively small amounts of energy are so dangerous is that it's composed of a small number of relatively high-energy particles, rather than a large number of low-energy particles. Those high-energy particles basically act like little bullets, damaging or killing cells (which leads to radiation sickness) or, even worse in the long run, creating mutations in DNA (which leads to increased risk of cancer).

But, again, not all radiation affects the body equally.

Gamma radiation and beta particles are, per unit of energy, actually less dangerous than alpha particles, because they are so small they might actually pass through cells without affecting them. This is why you need more shielding for some forms of radiation than others: for X-rays, you need lead aprons, while alpha particles can be stopped by a single sheet of paper. On the other hand, the fact that just about anything can stop an alpha particle pretty much means that the large alpha particles are going to be stopped by, and transfer their energy, to whatever tissue is nearby them. Fortunately, all three of the isotopes of concern—iodine-131, cesium-137, and strontium-90—all decay by beta and gamma radiation, so we can ignore this particular complication for a moment. [Also, it should be noted that alpha particles inflict far more damage when they enter the body than when they are outside; outside, they are basically all stopped by the skin, which is much less sensitive to radiation than most internal tissues.]

If you multiply the number of rads from these isotopes by a weighting factor based on the relative vulnerabilities of various types of tissues (for example, your eyes are more easily damaged by radiation than your skin), you get the roentgen equivalent in man, or rem level. This is the number you most often hear quoted on the TV (although if you read a scientific paper, you may see the sievert, which is equivalent to 100 rems).

Now here's the important thing in determining the hazard from radioactivity. What matters is both the number of rems and the rapidity of the dose. Most Americans are exposed to something on the order of 300-600 millirems of radiation each year (a millirem is 1/1,000th of a rem).

Some of the power plants in Japan have been cited as causing exposure levels of 400 millirems per hour. In other words: one hour near those reactors subjects tissue to as much radiation as a full year of everyday life. Please note that I am not saying that the people living in the towns near the reactor are being exposed to that much radiation; the dosage drops proportionally with distance (the farther away, the lower the dose, in much the same way that the light from a flashlight becomes dimmer and more diffuse the further it travels).

A sudden dose of less than 25 rems—that would be about two days' exposure to the levels cited near the plant—generally does not lead to any sort of acute radiation poisoning. It does, however, pose a potential cancer risk later in life.

Lesions (e.g., bleeding, sores on the skin) become visible with a sudden dose on the order of 50-100 rems—four to eight days' exposure at 400 millirems/hour. The LD50—the dose at which about 50 percent of people exposed will die within ~30 days—is on the order of 200 rems, which would be more than a week's exposure at those massively high levels. [On Sunday night, radiation levels were about 100 times lower, which would require far too long an exposure to cause acute radiation poisoning.]

Let me close by pointing out that things right now are scary. Nobody can be happy about the fact that radioactive isotopes are being vented into the atmosphere to prevent the possibility of a massive explosion. But, after reading this diary, I hope you can understand why that is vastly, vastly preferable to a sudden explosion. [If you'd like more technical details, such as the formula for calculating rads, please ask; I'll be glad to answer questions as best I can.]

Updated by Samer at Tue Mar 15, 2011 at 08:24 PM EDT

As cwillis notes below, that number of "400 millirems per hour" was actually "400 miliisieverts  per hour"—40,000 millirem, which is obviously 100 times higher. That said, later that day, the reported number had fallen to 0.6 millisieverts, or 60 millirems.

Originally posted to Samer on Mon Mar 14, 2011 at 10:06 PM PDT.

Also republished by Nuclear Free DK, SciTech, Nuclear dkos, and Community Spotlight.

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Comment Preferences

    •  Announcements are in microsieverts. (9+ / 0-)

      This is the common unit for worldwide radiation releases.

      REM is Roentgen Equivalent Man for radiation absorption and resulting damage. Conversions differ with which forms of radiation are present.

      SIEVERT (Sv) is System International dose equivalent.

      1 Sievert unit = 100 REM.

      Contrary to international scientific usage, much of the press is using "ms" and "msv" for microsieverts, not miliisieverts. Lord knows where that started.

      By way of comparison:

      1,000 microsieverts ==EQ Normal annual dose

      2,200 microsieverts ==EQ CT scan typical dose

      8,500 microsieverts ==EQ 100 day flights HNL-to-NRT

      10,000,000 microsieverts EQ Chernobyl firefighter exposure

      50,000,000 microsieverts EQ Cancer treatment at the tumor

      HNL is Honolulu International.

      NRT is Tokyo.

      BTW: sensible actions inside Japan:

      1. Take the potassium iodide (KI) tablets to forestall delayed cancers.

      2. Wear a very good mask -- either an N99 or N100 -- 24/7.

      BTW: N99s are easy to find. $30 in the U.S. Prevent virtually all of the dangerous air borne ingestion.

      I do work in New York. Never get on that bus without one in my ruck. (I'm a 9/11er.)

      Financial capitalism's criminals + Angry White Males + KKK wannabes + Personality Disorder delusionals + George Will =EQ= The GOPer Base

      by vets74 on Tue Mar 15, 2011 at 10:23:19 AM PDT

      [ Parent ]

      •  No eating, drinking or smoking (4+ / 0-)
        Recommended by:
        Samer, Deep Harm, billmosby, vets74

        were always prohibited during drills when I worked at TMI because we were simulating an event and that helps to keep you from ingesting bad stuff.

        •  In the old days,... (1+ / 0-)
          Recommended by:
          vets74

          I worked at Argonne-West (in Idaho, formerly a part of Argonne National Laboratory) in the 80s thru 2005. Down the hall from where I worked there were numerous radioactive material gloveboxes and chemical hoods , all used for doing chemistry on radioactive substances. The hoods had brackets that had been used in the 50s and 60s to support ash trays, according to my boss who dated from those times. And they were well used at the time, too, according to him.

          How times change, lol.

          Moderation in most things. Except Reactors. IFR forever!

          by billmosby on Tue Mar 15, 2011 at 02:01:31 PM PDT

          [ Parent ]

      •  True, but they [also] talk about it in mrems in (2+ / 0-)
        Recommended by:
        vets74, hopeful human

        Congress and on the news here in the US.

        We don't want our country back, we want our country FORWARD. --Eclectablog

        by Samer on Tue Mar 15, 2011 at 10:49:42 AM PDT

        [ Parent ]

        •  Prononounced "em rems" with no idea (0+ / 0-)

          whether that's "micro" or "milli" ?

          I'm reminded of the Confederate who complained that the most of the leadership was drunk most of the time.

          Ours seem to be drunk on something.

          (My guess for Palin and Michele MnAhole is that they're diet pill addicts. Just a guess.)

          Financial capitalism's criminals + Angry White Males + KKK wannabes + Personality Disorder delusionals + George Will =EQ= The GOPer Base

          by vets74 on Tue Mar 15, 2011 at 02:10:52 PM PDT

          [ Parent ]

          •  In general, if they're talking about mrems, it's (2+ / 0-)
            Recommended by:
            vets74, wader

            millirems.

            Microrems, from a practical standpoint, are too insignificant to merit mention on the news.

            We don't want our country back, we want our country FORWARD. --Eclectablog

            by Samer on Tue Mar 15, 2011 at 02:13:55 PM PDT

            [ Parent ]

            •  Think that would stop 'em ? (0+ / 0-)

              Even slow 'em down ?

              Worst Case Scenario is that TEPCO solves everything and there's no story any more.

              Talking heads over the cliff like lemmings....

              Financial capitalism's criminals + Angry White Males + KKK wannabes + Personality Disorder delusionals + George Will =EQ= The GOPer Base

              by vets74 on Tue Mar 15, 2011 at 06:32:49 PM PDT

              [ Parent ]

      •  The three primary things (1+ / 0-)
        Recommended by:
        vets74

        KI prevents uptake of iodine by the thyroid and retention of radioactive iodine. It's not 'anti-cancer', it keeps the radiation from accumulating inside your body.

        Likewise, Prussian Blue [Radiogardase] works to flush cesium out quickly, and high doses of calcium serves to prevent uptake of strontium90.

        Republicans totally abandoned conservatism in the 1980s ..

        by shpilk on Tue Mar 15, 2011 at 05:11:59 PM PDT

        [ Parent ]

        •  BTW: Goldwater was a conservative. (0+ / 0-)

          These guys 'n gals ???

          They sound like addicts to me. Diet pills, coke, whatever.

          Financial capitalism's criminals + Angry White Males + KKK wannabes + Personality Disorder delusionals + George Will =EQ= The GOPer Base

          by vets74 on Tue Mar 15, 2011 at 06:36:26 PM PDT

          [ Parent ]

    •  thank you (4+ / 0-)
      Recommended by:
      Samer, Odysseus, hopeful human, maryabein

      sooo much for this series.

      trying to make sense of reports by media people who do not know what they are doing is a big problem.

      personally, interpreting these units of measure is a big problem.  i understand the science in general, but find it almost impossible to remember what these units represent and then to do conversions from reports is pretty much impossible on the fly, so this is very useful.

      I am awaiting delivery of my new DK4 signature

      by BlueDragon on Tue Mar 15, 2011 at 11:33:41 AM PDT

      [ Parent ]

  •  I'm sorry I missed part 1 and 2 (12+ / 0-)

    Would you mind if I published your diaries to SciTech?

    •  Not at all. nt (5+ / 0-)

      We don't want our country back, we want our country FORWARD. --Eclectablog

      by Samer on Mon Mar 14, 2011 at 10:16:30 PM PDT

      [ Parent ]

      •  If you lived in the northwest, and God forbid (3+ / 0-)
        Recommended by:
        aitchdee, vets74, BlueDragon

        a plume did start moving off the Japanese coast, would it make a lot of sense for my pregnant daughter in law to leave, for at least a few weeks? Just to avoid the immediate exposure? Is there anyway to determine how much radioactivity would be left in the ground?

        Sorry for such simple questions.

        My idea of an agreeable person is a person who agrees with me. Benjamin Disraeli

        by pvmuse on Tue Mar 15, 2011 at 01:40:12 AM PDT

        [ Parent ]

        •  If you mean the NW USA, then that would be silly. (6+ / 0-)

          Even NW Japan is fine, even if the wind changes. No smoke particles large enough to still be emitting radiation would possibly make it that far. It would be like trying to catch a whiff of a smell from a brushfire in Japan.

          I'm writing in Lizard People on my next ballot.

          by George Hier on Tue Mar 15, 2011 at 02:33:10 AM PDT

          [ Parent ]

          •  Thanks, I was asking Samer the question. (8+ / 0-)

            Too many people have called things silly over the last 4 days, and now more scientists are saying that this could evolve into something much worse than Chernobyl.

            The amount of radioactivity in the number 2 reactor containing the spent rods, could alone hold much more plutonium than Chernobyl released.

            I was wondering about the specific amount of dangerous isotopes that would be present in a large plume.

            Several hours ago the New York Times reported that all remaining workers trying to contain the situation were ordered to leave, hopefully that has not occurred, because that to me would indicate all the reactors are being abandoned.

            With a total of 6 reactors now under some type of failure or meltdown, I don't think it is unreasonable to think of worst case scenarios.

            My idea of an agreeable person is a person who agrees with me. Benjamin Disraeli

            by pvmuse on Tue Mar 15, 2011 at 03:04:04 AM PDT

            [ Parent ]

            •  pvmuse, to answer your questions: (6+ / 0-)
              A plume did start moving off the Japanese coast, would it make a lot of sense for my pregnant daughter in law to leave, for at least a few weeks? Just to avoid the immediate exposure? Is there anyway to determine how much radioactivity would be left in the ground?

              It's difficult to know a priori how much of those isotopes would be released, but it would almost certainly be a mixture of all three. There's also no layman's test that can tell you how much of each one is present. Needless to say, university/industry/government labs should have all the equipment needed to answer that question. [A Geiger counter could tell you how many atoms are disintegrating, but that doesn't tell you all that much.]

              In the worst case scenarios (large-scale release of isotopes that makes its way toward the US), I would definitely consider having your pregnant daughter-in-law leave the area, if only because a child in utero is more sensitive to radiation than an adult. [This is why the recommendations for KI prophylaxis are different for pregnant women.]

              We don't want our country back, we want our country FORWARD. --Eclectablog

              by Samer on Tue Mar 15, 2011 at 09:49:28 AM PDT

              [ Parent ]

            •  precisely (2+ / 0-)
              Recommended by:
              Samer, pvmuse
              Too many people have called things silly over the last 4 days, and now more scientists are saying that this could evolve into something much worse than Chernobyl.

              So when I just saw CNN reporting that some scientists are saying this could be worse than Chernobyl, we should call them silly until it is too late to take any precautions?

              I don't want to be alarmist, but I'll be damned if I won't look at all the possibilities as a way to understand what is happening and what might happen.

              The reality is that I consumed a lot of radiation in milk during childhood in the 50s and 60s.  Most people don't even know this is reality to this very day.

              http://www.cancer.gov/...

              I am awaiting delivery of my new DK4 signature

              by BlueDragon on Tue Mar 15, 2011 at 11:49:27 AM PDT

              [ Parent ]

            •  Concentration matters (1+ / 0-)
              Recommended by:
              Samer

              You have radioactive isotopes in your body right now. Radioactive carbon, calcium, iodine, you name it. You probably even have some amount of deuterium (heavy water) in your body right now. And our hunter gatherer ancestors did too, long before we began splitting atoms ourselves.

              If you are truly concerned, buy a Geiger Counter.

              But remember that the west found out about the Chernobyl accident when a nuclear power plant in Scandinavia had its own radiological alarms triggered and it took them a while to realize it wasn't their plant.

              In other words, the whole world has detectors all over the place.

              I don't think there is much threat more than a few hundred miles from any of these reactors in even a worst case accident. Direct exposure, ground water contamination, and long term bioaccumulation are probably the biggest concerns. You are unlikely to have the kind of dispersal you had at Chernobyl because the worst case scenario for this kind of reactor doesn't involve a graphite core fire. It is the escape of molten nuclear fuel.

              Make no mistake, that is a very serious problem. But I doubt it will directly affect the US. I'm sure there will be some elevation of the background radiation. But I think dilution will make it not a severe issue even in a worst case scenario.

              But this could be a very serious problem for Japan.

              I'm semi serious when I suggest you buy a Geiger Counter. Although I note that the site I linked has sold out of most models in the last 24 hours. Provided you learn how to use it properly it can reassure you, if you need a few hundred dollars of reassurance.

              I'm not sure of the general availability of ionizing radiation dosimeters, which would be even better. But be careful. Most "dosimeters" are either for noise or for EMF. Nothing to do with ionizing radiation.

              Another indication that this is probably not something to worry about, go to a site like amazon.com and start shopping for geiger counters or dosimieters. You will quickly see that "customers also bought" is a list of paranoid survivalist gear.

              If you live anywhere near a nuclear power plant, their alarms will be going off before your exposure is anywhere near dangerous.

          •  You see the plume from Mt. St. Helen ? (1+ / 0-)
            Recommended by:
            Samer

            Peace of mind is worth getting a mask.

            No matter the calculations, the girl will sleep better knowing she's gone the extra mile.

            Financial capitalism's criminals + Angry White Males + KKK wannabes + Personality Disorder delusionals + George Will =EQ= The GOPer Base

            by vets74 on Tue Mar 15, 2011 at 10:29:33 AM PDT

            [ Parent ]

        •  Buy her an N99 or N100 mask. (1+ / 0-)
          Recommended by:
          Odysseus

          My N99 cost me $30 at Home Depot.

          Hell, that's less than a carton of cancer sticks.

          Financial capitalism's criminals + Angry White Males + KKK wannabes + Personality Disorder delusionals + George Will =EQ= The GOPer Base

          by vets74 on Tue Mar 15, 2011 at 10:27:32 AM PDT

          [ Parent ]

        •  I feel for you! (4+ / 0-)
          Recommended by:
          pvmuse, Samer, mahakali overdrive, hester

          Our pregnant daughter, 7 months, is in Iwakuni.  We really pushed her to come home this past weekend.  But she is listening to her husband, Marine Officer, that if it were dangerous the military would evacuate her.  We couldn't push her any harder because the stress was too much for her.

          While she is far away, Dr. Stephen Chu said on CNN last night that cancer rates could spike for people within a 1000 mile radius.  

          My nerves are shot.  And I am not a worrier by nature. And I am not one to intrude on the kids' decisions.

          "Since when did obeying corporate power become patriotic." Going the Distance

          by Going the Distance on Tue Mar 15, 2011 at 12:51:39 PM PDT

          [ Parent ]

          •  I will pray for your daughter. (3+ / 0-)
            Recommended by:
            Samer, mahakali overdrive, hester

            Maybe you could write/email your son-in-law directly about your concerns, and he could revisit the decision to send her home. I understand about not wanting to alarm her anymore, I have been careful about talking to my son and daughter-in-law as well.

            My idea of an agreeable person is a person who agrees with me. Benjamin Disraeli

            by pvmuse on Tue Mar 15, 2011 at 01:30:18 PM PDT

            [ Parent ]

  •  Forgive my naivete (4+ / 0-)
    Recommended by:
    rfall, Samer, aitchdee, vets74

    but can someone discuss why radiation is poisonous?  I mean simply the chemical effects--why does it cause lesions and death?  And why cancer in the long term?

    Ordinary political process is dead. The Supreme Court killed it. In Chambers. With a gavel.

    by Publius2008 on Mon Mar 14, 2011 at 10:27:12 PM PDT

    •  The answer is in the diary: (7+ / 0-)
      Those high-energy particles basically act like little bullets, damaging cells (which leads to radiation sickness) or, even worse in the long run, creating mutations in DNA (which leads to increased risk of cancer).

      The details of how the cells are damaged determine how the damage is expressed, of course.  Someone with more knowledge of cell biology than I would have to explain how.

      "Ridicule is the only weapon which can be used against unintelligible propositions." - Thomas Jefferson

      by rfall on Mon Mar 14, 2011 at 10:29:32 PM PDT

      [ Parent ]

      •  Damage to cells and DNA is caused (7+ / 0-)

        by the equivalent is teeny cuts made by 'burning' of radioactivity, which can disrupt the way cells replicate themselves when they reproduce. Think of it as zapping a letter or word in a message.

        Some of the particles in 'fallout' are so similar to what the bodies takes in as building blocks that they become part of the body and do their damage in the organs where they are absorbed. Thyroid (iodine) and bone (strontium 90 in place of calcium).

        One of Ted Kennedy's sons lost a leg to bone cancer as a child, probably due to Strontium 90 in milk from above ground nuclear tests.

        Look up Dr. Helen Caldicott on the subject of radiation and children's health. She explains it well.

        •  Plume? (1+ / 0-)
          Recommended by:
          pvmuse

          I thought that radiation clouds don't diffuse evenly so much as they form a plume which is carried by the wind.

          Note how statistics are done not according to distance but by upwind vs. in path of the plume:
          http://www.nirs.org/...

          •  Thanks for the link (1+ / 0-)
            Recommended by:
            aitchdee

            My idea of an agreeable person is a person who agrees with me. Benjamin Disraeli

            by pvmuse on Tue Mar 15, 2011 at 01:33:55 AM PDT

            [ Parent ]

            •  As LNK just mentioned (2+ / 0-)
              Recommended by:
              Ice Blue, cassandracarolina

              ...with respect to your DIL--I think Dr. Helen Caldicott will be an excellent resource for you. She has a new(ish) book out.

              Be forewarned that there will be those who will call her an hysteric or a nutcase or misinformed. Learn everything you can about the science and then decide for yourself; that's what I'm doing.

              God bless our tinfoil hearts.

              by aitchdee on Tue Mar 15, 2011 at 04:53:53 AM PDT

              [ Parent ]

          •  asdf (2+ / 0-)
            Recommended by:
            gchaucer2, cassandracarolina

            This NIRS.org site isn't really a great site to get scientific information about nuclear reactors or problems with it.

            To answer your question, each different type of isotype would travel a certain distance based on weight and chemical reactivity.  Something like a radioactive cobalt particle (a common material in reactor grade metals) wouldn't travel as far as say a radioactive calcium particle based on weight.  Something like a radioactive oxygen particle wouldn't travel that far due to its extremely high reactivity with other materials.  So, no, a radiation cloud does diffuse fairly quickly.

            Statistics in that article are highly selective samples to maximize number of cancer instances versus an extremely small sample size, which makes things look horrible anywhere near a reactor or relating to people .  I remember reading a study while an operator in the Navy stating that no attributable cancer case from a previous naval operator came from working at the plant and this study consisted of something like 10,000 previous operators, yet according to the article you linked, a person operating a reactor will be 250% more likely.  If that study referenced in the link was anywhere near credible, the naval operators study would have shown something.

            "It has been said that politics is the second oldest profession. I have learned that it bears a striking resemblance to the first." - Ronald Reagan

            by erush1345 on Tue Mar 15, 2011 at 02:54:47 AM PDT

            [ Parent ]

        •  It's not responsible to attribute a cause to (6+ / 0-)
          Recommended by:
          Samer, T100R, ebohlman, OHdog, Odysseus, mojo workin

          Ted Kennedy's son's cancer without evidence. Especially to do so specifically regarding Sr 90 in milk. Sadly, kids get cancer. If this poor kid were known to been exposed at some time to a specific source of ionizing radiation, then one might be able to speculate on the cause. But everyone living during the 40's, 50's and 60's has been exposed to Sr 90 in milk etc. Only a very small subset got cancer and though Sr 90 exposure is a risk, there are many other risks, including genetics, such that case of Teddy's son can't honestly be attributed to it. Hence your statement that his was "probably" due to Sr 90 in milk is speculation AT BEST. It is actually much closer to nonsense.

    •  Radioactivity, part 4, maybe? :) Seriously, though (12+ / 0-)

      In the short run the answer is this:

      You can think of radiation as releasing tiny atom/electron-sized bullets into cells. Some of them are bigger, some of them have more energy.

      If they cause enough destruction in the cell, that kills the cell; kill enough cells in a certain area, and you get lesions.

      If that damage happens to the DNA in a cell, however, you may not kill the cell, but you may mutate the DNA. And mutations in DNA alter how the cell runs itself; change the wrong segments of DNA, and cancer can result.

      We don't want our country back, we want our country FORWARD. --Eclectablog

      by Samer on Mon Mar 14, 2011 at 10:30:47 PM PDT

      [ Parent ]

    •  In addition to the other replies: (9+ / 0-)

      Cells also have the ability to detect damage to their DNA, and if too much damage is found (that cannot be repaired), they will trigger suicide, called "apoptosis". Tens of billions of your cells die everyday due to this process (though not necessarily from radiation damage). Obviously, too much cell death and your immune system is overwhelmed, not to mention your other bodily systems.

      When cells don't kill themselves from damage... well, that's when you get cancer.

      I'm writing in Lizard People on my next ballot.

      by George Hier on Tue Mar 15, 2011 at 02:40:54 AM PDT

      [ Parent ]

  •  "Average" dose to members of the public (7+ / 0-)

    ...from background radiation varies dramatically based on location in the US.

    In addition, other factors which affect averages are exposure to medical X-rays and flight time aboard aircraft, all of which increase exposure to ionizing radiation (which is what alpha, beta and gamma radiation is).

    BTW, for us US residents, interesting data can be found here and here.

    "Ridicule is the only weapon which can be used against unintelligible propositions." - Thomas Jefferson

    by rfall on Mon Mar 14, 2011 at 10:33:44 PM PDT

    •  Life-time accumulation is also factor. Son worked (3+ / 0-)
      Recommended by:
      cassandracarolina, Samer, Odysseus

      at Three Mile Island {TMI} as recovery engineer.  All workers wore a radiation meter.  When total accumulation reacted a critical level they were pulled off the job.  They had to account for off-plant exposures, like dental x-rays, too.  One shot repair workers had a longer work day allowed, but daily supervisers and working engineers had lesser exposure allowed for a single day of work.  Four hours working near the core in full radiation gear was the limit for the day.  Remember, I'm talking about FIVE YEARS after the release of radiation from the cooling towers, for that was how long TMI waited for the tower of "cool down" before cleanup was done in earnest.

  •  Japan's situation is dire... (2+ / 0-)
    Recommended by:
    blueoasis, hopeful human

    Am I wrong?

  •  To understand the effects of very high doses (5+ / 0-)

    ...of radiation over a short period of time, read this Wikipedia entry.

    The relevant part:

    On May 21, 1946, Slotin and seven other colleagues performed an experiment that involved the creation of one of the first steps of a fission reaction by placing two half-spheres of beryllium (a neutron reflector) around a plutonium core. The experiment used the same 6.2-kilogram (13.7 lb) plutonium core that had irradiated Harry K. Daghlian, Jr., later called the "Demon core" for its role in the two accidents. Slotin grasped the upper beryllium hemisphere with his left hand through a thumb hole at the top while he maintained the separation of the half-spheres using the blade of a screwdriver with his right hand, having removed the shims normally used.[2] Using a screwdriver was not a normal part of the experimental protocol.

    At 3:20 p.m., the screwdriver slipped and the upper beryllium hemisphere fell, causing a "prompt critical" reaction and a burst of hard radiation.[9] At the time, the scientists in the room observed the "blue glow" of air ionization and felt a "heat wave". In addition, Slotin experienced a sour taste in his mouth and an intense burning sensation in his left hand.[2] Slotin instinctively jerked his left hand upward, lifting the upper beryllium hemisphere and dropping it to the floor, ending the reaction. However, he had already been exposed to a lethal dose (around 2100 rems, or 21 Sv) of neutron and gamma radiation.[14] Slotin's radiation dose was equivalent to the amount that he would have been exposed to by being 1500 m (4800 ft) away from the detonation of an atomic bomb.[15]

    As soon as Slotin left the building, he vomited, a common reaction from exposure to extremely intense ionizing radiation.[2] Slotin's colleagues rushed him to the hospital, but irreversible damage had already been done. His parents were informed of their son's inevitable death and a number of volunteers donated blood for transfusions, but the efforts proved futile.[2] Louis Slotin died nine days later on May 30,[16] in the presence of his parents. He was buried in Winnipeg on June 2, 1946.[2]

    Note:  this is for education only--nothing like this could ever, under any circumstances, happen to the general public.

    "Ridicule is the only weapon which can be used against unintelligible propositions." - Thomas Jefferson

    by rfall on Mon Mar 14, 2011 at 10:37:16 PM PDT

  •  You forgot to mention the other, much worse (3+ / 0-)
    Recommended by:
    Lefty Mama, aitchdee, Ice Blue

    kind of ionizing radiation.  Specifically, neutron radiation which is much more likely to make other things radioactive (induced radioactivity) than either alpha, beta, gamma, or x-ray radiation.

  •  Someone actually tackling the science (9+ / 0-)

    vs   the OMG diary's, you get a rec just for that. What a relief.

    FDR 9-23-33, "If we cannot do this one way, we will do it another way. But do it we will.

    by Roger Fox on Tue Mar 15, 2011 at 12:09:45 AM PDT

    •  In my observation (2+ / 0-)
      Recommended by:
      politik, mahakali overdrive

      nearly everyone closely following the news out of Japan is also paying close attention to and asking questions of those who understand and can explain the science, and their help and guidance has been of tremendous value to me personally. The last couple of days has been all about learning for me: I'm alert and appropriately concerned, I think, but I'm not flipping out. Who is doing that? Where are the OMG diaries?

      God bless our tinfoil hearts.

      by aitchdee on Tue Mar 15, 2011 at 05:39:16 AM PDT

      [ Parent ]

  •  wonderful diary, thanks!! (4+ / 0-)

    When I was in college I spent a most fascinating month studying nuclear physics in Oak Ridge, Tennessee.

    My favorite "fact" from the class: Somebody asked how dangerous nuclear waste really is. The professor said, "Let me put it this way. If somebody pulled a rod out of a reactor and placed it on a highway, and you were driving towards it at 60 miles per hour, you'd be dead at about the time you were a mile away from it...."
    Even chernobl was protected enough that the rods weren't completely exposed to the naked environment. But yes, that's why you have to have very good containment vessels. This will not be anywhere near as bad as that. Small comfort, I know. The containment vessel is strong, AND because of the water cooling systems, the containment vessel has been protected from radiation during the lifetime of the plant - ergo, the steel has not been weakened by having to do most of the "containment" over its lifetime.
    "Not as bad as Chernobl" is still not good at all. We are lucky that we regulated our nuclear power to death, although coal turns out to be terrible, too.

    In a democracy, everyone is a politician. ~ Ehren Watada

    by Lefty Mama on Tue Mar 15, 2011 at 12:59:29 AM PDT

    •  tipped and rec'd, but pls fix sentence fragment (0+ / 0-)
      Lesions become visible with a sudden dose on the order of 50-100 rems—four to eight days' exposure at 400 millirems/hour—while 50 percent of people exposed to doses of 200 rems or more, which would be more than a week's exposure at those massively high leve

      The clause beginning "while 50 percent of people exposed..." needs a predicate after the clause beginning "which would be..."

      It appears to suggest that 50 percent of people exposed to 20 rem would die acutely, ie that 200 rem is the LD50.

      There's no such thing as a free market!

      by Albanius on Tue Mar 15, 2011 at 05:34:39 AM PDT

      [ Parent ]

    •  I'm so glad you saw this! (1+ / 0-)
      Recommended by:
      Lefty Mama

      I was just about to post a comment to you in the other diary with the link. Good stuff, eh?

      God bless our tinfoil hearts.

      by aitchdee on Tue Mar 15, 2011 at 05:40:33 AM PDT

      [ Parent ]

  •  drop with distance (2+ / 0-)
    Recommended by:
    politik, LookingUp
    the dosage drops proportionally with distance

    I thought it dropped as the square of the distance, not proportionally.

    I was corrected the other day by my own casual (idiomatic) use of the word "proportional" rather than the mathematically rigorous definition:

    two quantities are proportional if they vary in such a way that one of them is a constant multiple of the other.

    and ultimately it is an important distinction, I think.

    Causation was, is, and ever shall be a slippery bitch, so we're best sticking with noting the facts

    by jam on Tue Mar 15, 2011 at 05:47:27 AM PDT

    •  The square of the distance wouldn't be (0+ / 0-)

      proportional as well?

    •  Inverse square law (1+ / 0-)
      Recommended by:
      Samer

      All forms of radiation obey it. Your light bulb light obeys it. The energy received per unit area or mass varies as the inverse of the square of the distance. In other words, if you double your distance to the source, your exposure is one quarter what it was.

      This is all well and good, but the problem with nuclear accidents really isn't with direct exposure from a point source, it is from the dispersal of radioactive elements.

      One gram of radioactive iodine outside your body is really no threat at all. One gram of radioactive iodine in your glass of drinking water is a serious potential risk to your thyroid.

      "Ionization" refers to the process of making ions out of atoms or molecules that were electrically neutral. Normally an atom has the same number of protons and electrons. Radiation can strip away one or more electrons which changes the chemical nature and behavior of the atom or molecule. In the case of large molecules like proteins, it can break them into pieces. Neutron bombardment can actually change the nucleus of an atom, making it unstable and thus a radioactive isotope of the element.

      At some level this is happening all around you and within you all the time. Cosmic rays are shooting through your body right now from the explosion of distant suns, and some of those are hitting proteins in your body and damaging them.

      Normally, if this leads to cell death an immune system cell will "eat" the dead cell and you'll go on normally. Sometimes the damage will be to some part of the genetic material, either nucleic or mitochondrial DNA, and this doesn't lead to cell death, but rather malfunction. This is one way cancer can start.

      Radiation isn't "magic." By analogy, tissue damage from radiation isn't any more remarkable than tissue damage by fire. You are talking about the body absorbing a large amount of energy causing physiochemical changes to the tissues, most of which are bad for you.

      The fact that radiation isn't detectable by our senses gives it most of its "fear" factor. You can see fire. You can feel heat. You know how to avoid it. How do you know if the beef you ate fed on grass irradiated in nuclear tests? How do you know if there is strontium-90 in that glass of water?

      You don't. That's what makes it scary.

      Again, generalizing, the faster the tissue divides/reproduces the more quickly it shows damage from radiation. This is why vomiting and diarrhea are the first symptoms of acute radiation poisoning. The lining of the GI tract from the mouth all the way to the anus is among the fastest dividing tissues in the body. These can be massively damaged by a high dose of any kind of ionizing radiation.

      The slowest dividing tissues are the last to show signs, but often because they are slow to be replaced, they show up as long term increased cancers in an exposed population.

       

      •  It's not necessarily an inverse-square law, though (1+ / 0-)
        Recommended by:
        evilpenguin

        because it's not a case where there are no outside forces to modify it. In the immediate vicinity of the reactors, yes, it's 1/r^2. But that starts breaking down once you get outdoors and have winds blowing the radiation around. As a guest on Rachel Maddow's show noted, they're seeing big variations in exposure over relatively small distances (and time periods). I'm confident in saying "the farther away, the less the effect," but I don't know enough about the exact situation to say 1/r, 1/r^2, etc.

        We don't want our country back, we want our country FORWARD. --Eclectablog

        by Samer on Tue Mar 15, 2011 at 08:13:45 PM PDT

        [ Parent ]

        •  Yes, I was trying to say that (0+ / 0-)

          I guess I didn't make it clear enough. It is still inverse square law when you drink contaminated water. But the distance from such a contaminant to the cell is microns in that case. That's what I was trying to say there. When contaminants are dispersed, it is your distance from the contaminant that matters, not the plant!

          So I violently agree with you here! ;)

  •  So it's like a horsepower equation (1+ / 0-)
    Recommended by:
    Samer

    Getting the 'punch' over a longer duration is preferable to getting it all in a short sharp moment...as well as avoiding a much larger 'punch'.

    Or in martial arts - much of the trick is concentrating the body's momentum into as small an area of contact and time as possible.

    1. man stomps hard on floor
    2. pivots hip just so
    3. drives momentum into striking arm
    4. arm directs force into blade of hand (or bend of knuckles)
    5. maximizes force of contact over as short a duration of time as possible
    6. impressive force multiplier ensues... on the order of 5-10 times what a simple punch could deliver. I suppose some specialists in certain moves (like, for competitions) could best that greatly.

    (If I understand it right, that's how normal strength persons can do the trick with hacking cement blocks and not so much as breaking their skin...but you have to get the timing right.)

    So... spreading out the exposure keeps "us" ( the cement blocks in this second metaphor) relatively intact.

  •  Very nice. Would you care to comment on (3+ / 0-)
    Recommended by:
    Samer, wilderness voice, Odysseus

    this story:

    The Transportation Security Administration announced Friday that it would retest every full-body X-ray scanner that emits ionizing radiation — 247 machines at 38 airports — after maintenance records on some of the devices showed radiation levels 10 times h

    I don't have much scientific training, but it seems to me that:

    1.  Radiation must be properly measured or it cannot be controlled.

    2.  Your analogy of the one ton of trash on a one-acre field being either 2,000 pounds spread out all over the field vs. one old car seems entirely appropriate to the TSA scanner situation.  The radiation is concentrated on the top layer of the skin rather than spread throughout the body.  

    That would seem to make official statements that claim there is no risk ...

    To put things in perspective, here are some sources of radiation you may not have been aware of:
    * One year of naturally occurring background radiation: 300 millirem
    * Annual recommended limit to the public of radiation from man-made sources: 100 millirem
    *Chest X-ray: 10 millirem
    * Flight from New York to Los Angeles: 4 millirem
    * One day of natural background: 0.1 millirem
    * Drinking three glasses of water a day for a year: 0.045 millirem
    * One backscatter X-ray scan: Approximately 0.005 millirem

    ... misleading because of the failure to calculate the body mass of the affected area (the skin).

    You have exactly 10 seconds to change that look of disgusting pity into one of enormous respect!

    by Cartoon Peril on Tue Mar 15, 2011 at 08:00:10 AM PDT

    •  Actually, one of the good things about the skin (3+ / 0-)
      Recommended by:
      gchaucer2, drmah, ebohlman

      is that it is far more resistant to the effects of radiation than most of the rest of the body. Remember this quote above:

      If you multiply the number of rads from these isotopes by a weighting factor based on the relative vulnerabilities of various types of tissues, you get the roentgen equivalent in man, or rem level.

      That weighting factor is about 5-10 times smaller for the skin than for the rest of the body.

      So even if they are off on the math, I can't say that the figure of 0.005 mrem is necessarily far off. It might be 2-3 times higher, perhaps, but I would be surprised if it were off by 10x or more.

      We don't want our country back, we want our country FORWARD. --Eclectablog

      by Samer on Tue Mar 15, 2011 at 08:31:39 AM PDT

      [ Parent ]

  •  This disturbing comment (2+ / 0-)
    Recommended by:
    Samer, BlueDragon

    from a friend who is a member of radsafe (comment board for International Radiation Protection (Health Risk) Mailing List):

    One more interesting tid-bit: the dosimetry service for the power plant is located miles away to the south, and technicians can't access the plant because the rails are out.  So - it seems they will have to exercise their best judgment based on field instruments to calculate worker exposure since the badges won't be getting processed.

    " My faith in the Constitution is whole; it is complete; it is total." Barbara Jordan, 1974

    by gchaucer2 on Tue Mar 15, 2011 at 09:04:19 AM PDT

  •  I appreciate the details you give here (2+ / 0-)
    Recommended by:
    cassandracarolina, BlueDragon

    I am radiation safety officer of my company and was thinking of doing a diary something like this.  I thank you for doing a fine job here in giving an overview that leads neither to panic nor complacency.  

    You could have noted that the rad to REM equivalence is highly dependent on the tissue involved.  A given dose in rads will much more harmful to the eyes, for example, than to the skin or to the entire body.  

    Real plastic here; none of that new synthetic stuff made from chicken feathers. By the morning of 9/12/2001 the people of NYC had won the War on Terror.

    by triplepoint on Tue Mar 15, 2011 at 09:06:43 AM PDT

  •  Am I the only one who thinks (0+ / 0-)

    that staying indoors to avoid radiation is completely futile?

    •  It's not _completely_ futile (5+ / 0-)

      It's not 100% effective, either, but the walls of a house will stop a significant percentage of the radiation. [What that percentage is, I can't say, but it's a lot more than 0.]

      We don't want our country back, we want our country FORWARD. --Eclectablog

      by Samer on Tue Mar 15, 2011 at 09:36:00 AM PDT

      [ Parent ]

      •  any physical barrier (0+ / 0-)

        provides some protection.

        this is why a lead barrier when you get an xray is effective.

        obviously, we don't have lead walls in our homes, but barriers are effective in reducing exposure.

        gamma rays go through almost everything? but other types of radiation can be reduced.

        any amount of reduction is better than no reduction as radiation damage is cumulative.

        I am awaiting delivery of my new DK4 signature

        by BlueDragon on Tue Mar 15, 2011 at 11:43:12 AM PDT

        [ Parent ]

      •  Right (1+ / 0-)
        Recommended by:
        Samer

        And remember that biggest threat is inhaling or ingesting contaminants. With the types of reactors here, ground water contamination is going to be the biggest problem, but any contaminants that are airborne will be at much lower concentrations inside than out.

        But basically the best thing to do is to be as far as possible from the zone of contamination.

        Part of the problem here is that with the quake and the tsunami I'm sure this is problematic for some people.

  •  You need to clarify that alpha radiation (3+ / 0-)
    Recommended by:
    Samer, SLKRR, BlueDragon

    is more damaging when it is deposited internally or in the lungs. Alpha particles have such a short range through solids that, generally, they don't penetrate skin.

    look for my eSci diary series Thursday evening. "It's the planet, stupid."

    by FishOutofWater on Tue Mar 15, 2011 at 09:27:07 AM PDT

  •  Just read all 3... (2+ / 0-)
    Recommended by:
    BlueDragon, Odysseus

    I am curious as to why you have neglected state in the issues of radioactive materials. Iodine has the problem of sublimating as a gas in its pure form making it very likely to spread.  Cesium and Strontium are solids making them less likely to escape and will have a shorter range than Iodine.  More of an issue with Cesium and Strontium is probably water solubility and whether droplets with dissolved ions were to escape.

    Also, what about the steam that is supposed to be radioactive?  Is that due to neutrons from the reactor creating tritium in the water, or are there dissolved reaction products?

    •  The reactions have stopped, so there should be no (2+ / 0-)
      Recommended by:
      BlueDragon, Odysseus

      neutrons, or fairly close to it.

      As far as state, I didn't talk about it because it was a case of losing the forest for the trees (in particular, talking about the "state" of very small numbers of atoms is almost meaningless). My goal was to focus on what happens to the isotopes themselves.

      We don't want our country back, we want our country FORWARD. --Eclectablog

      by Samer on Tue Mar 15, 2011 at 10:39:32 AM PDT

      [ Parent ]

  •  misprint? (3+ / 0-)
    Recommended by:
    Samer, vets74, BlueDragon

    "...while alpha particles can be stopped by a single sheet of paper.] On the other hand, the large alpha particles are pretty much guaranteed to rip through whatever tissue is nearby them."

    The fundamental cause of trouble in the world today is that the stupid are cocksure while the intelligent are full of doubt. Bertrand Russell

    by dskoe on Tue Mar 15, 2011 at 10:22:55 AM PDT

  •  Excellent diary (1+ / 0-)
    Recommended by:
    Samer

    I always tip for science!  ;-)

    O povo unido jamais será vencido

    by SLKRR on Tue Mar 15, 2011 at 11:13:40 AM PDT

  •  Did you mean most penetrating? (2+ / 0-)
    Recommended by:
    BlueDragon, Malachite

    You wrote:

    3. Gamma radiation, which are photons that carry energy. Of the three forms of radiation, gamma rays are the ones that carry the most energy.

    Alpha particles typically carry energies over 4 MeV, and gamma rays typically around 1 MeV or less.

    "Trust only those who doubt" Lu Xun

    by LookingUp on Tue Mar 15, 2011 at 11:17:12 AM PDT

  •  good diary, questionable comments (12+ / 0-)

    Good series of diaries, Samer. The Japanese trifecta has brought out the worst from so-called TV expert commentators: Larry Kudlow, “Republican thinker” (oxymoron) said that we should be grateful that the main impact was only that of people killed rather than economic hardships for Americans. Other ‘experts’ have said, be grateful because this pushed down the yen and boosted sales of US Treasury bonds.

    Unfortunately, Americans as a whole are scientifically illiterate and this illiteracy is constantly exploited, not only by Fox News and its ilk but also by people like RFK, Jr. Helen Caldicott is not as bad as RFK, Jr (I knew her former radiologist husband Bill, when they lived in Boston & I met her) but she is prone to the same leaps of faith- anyone who dies young must have been killed by radioactivity or environmental toxins. If you don’t know anything about electrons and chemical bonds you are not well educated and can’t understand how radioactivity and high oxygen exposures can hurt people, but you can know that radioactivity is harmful and that 100% oxygen can be harmful.

    EM Kennedy Jr was born in 1961, the greatest amount of radioactive fallout from testing occurred in the 1960s. Most US radiation from Sr 90 then was from milk and was at most 1% of background natural radioactivity. Today it is less than 1%, much much less if you get lots of X rays and CT scans. Natural radioactivity varies greatly – the largest component is from radon in the soil. Natural radioactivity is much greater in New Mexico and Colorado than in most states. Granite counter tops (I have one) bring a small increase in radioactivity, although it is not ingestible radioactivity. People who are so worried about plumes from Japan might test their homes for radon, a quantitatively much larger hazard. Several EPA websites have information about natural radioactivity and its geographical distribution. If you want to blame deaths and cancers on environmental factors, air pollution from gasoline and especially diesel exhaust have had far more effect than nuclear tests + nuclear power plants. I agree with Caldicott that nuclear tests are bad.

    Two things to think about:
    1. Libertarian “financial experts” like Keith Fitz-Gerald were saying even before all this that Japan was likely to default in the next year or two because of its high debt/GDP ratio. However, most Japanese debt is owned by Japanese citizens
    2. The 50 men who have stayed behind to work inside the reactor voluntarily accepted large radiation exposures for the good of their countrymen. We should all salute them. American workers might not be so conscientious. We’ll have to wait and see how Japan emerges from these multiple tragedies. I believe that they have a much greater ability and willingness to pull together than do Americans as a whole.

  •  I give props to NBC and MSNBC for relying (1+ / 0-)
    Recommended by:
    Samer

    on the Union of Concerned Scientists for many of their expert interviews. Some others have had faculty members from very-pro-nuclear energy programs who have given a rather  biased pro-industry viewpoint.

    I don't dislike all conservatives... mainly just the ones that vote Republican.

    by OHdog on Tue Mar 15, 2011 at 12:44:11 PM PDT

  •  Thank you for your series on this subject matter! (1+ / 0-)
    Recommended by:
    Samer

    I wish my teachers and professors had been as clear and concise as you have been when explaining such basic concepts as atomic number, isotopes, and radioactive decay!

    Your series has also been more through in explaining the processes of "how" and "why" than any other essay on the subject that I've read.

    "Most people would sooner die than think; in fact, they do so." ...Bertrand Russell

    by sebastianguy99 on Tue Mar 15, 2011 at 12:49:50 PM PDT

  •  One thing you might elaborate on... (3+ / 0-)
    Recommended by:
    sebastianguy99, Samer, Drama Queen

    is the distinction between radiation exposure and radiological material exposure (contamination). The press often uses the term "radiation" when they mean contamination. Although the levels of radiation measured in cities away from the power plant facilities may be relatively low, the fact that airborne radioactive particulates are present poses a different type of risk. And it isn't being quantitatively measured to my knowledge.

    As you suggest in your diary, particles emanating radiation from within the body are far more dangerous.

    The man who moves a mountain begins by moving away small stones. -Confucius

    by Malachite on Tue Mar 15, 2011 at 01:02:37 PM PDT

    •  Yes please! (2+ / 0-)
      Recommended by:
      Samer, Malachite

      Or you could write something on the matter as there are too many of us who are underprepared and underinformed including the press.

      "Most people would sooner die than think; in fact, they do so." ...Bertrand Russell

      by sebastianguy99 on Tue Mar 15, 2011 at 01:23:37 PM PDT

      [ Parent ]

      •  Here is my perspective... (2+ / 0-)
        Recommended by:
        sebastianguy99, Samer

        Nuclear power facilities have individuals trained in the measurement of air particulate and surface contamination. The group/department responsible is typically referred to as Health Physics.

        One can capture an air particulate sample by blowing air through a special filtering medium (imagine blowing air through a cotton sock to get an idea). This traps particulate matter in the air. By keeping the volume of air blown over the filter constant, and the surface area of the filter constant, one can take a reproducible/meaningful measure of radioactive particulate contamination. One would measure the "radiation" coming from the sample (in excess of background of course).

        I don't think anyone is doing this outside of the plant itself (if they are even bothering at the plant at this point). I could be wrong, but this is where I am trying to get traction and information. I'd like to hear more from the media along these lines.

        One can get a rough sense of contamination levels in neighboring cities by measuring radiation: the contaminated particles are after all "radiating" themselves. But this is still a kind of inferred measure. And it troubles me that we don't hear more about the danger of inhalation or ingestion of contaminated material. The skin for example is no longer useful as a layer of protection if the body has consumed matter that is radiating. So radiation that seemed innocuous before is suddenly not-so-innocuous. And it's inside the body, not easily scrubbed away.

        The man who moves a mountain begins by moving away small stones. -Confucius

        by Malachite on Tue Mar 15, 2011 at 02:28:48 PM PDT

        [ Parent ]

  •  For those who are panicky (2+ / 0-)
    Recommended by:
    Samer, FishOutofWater

    about potential impacts on the U.S. (unlikely, actually), there is a website that crowdsources radiation readings in real time from across the United States.

  •  thanks you for this real info (1+ / 0-)
    Recommended by:
    Samer

    Major props for not mentioning the go-industry standard BED or 'banana equivalient dose' that always seems to be bandied about by those who would make light of radiation exposure.  

     

    "Welcome to Costco, I love you" -- Greetings from "Idiocracy"

    by martinjedlicka on Tue Mar 15, 2011 at 01:45:12 PM PDT

    •  I see your point, but it is worth noting that (1+ / 0-)
      Recommended by:
      mojo workin

      bananas ARE radioactive, though the main radioactive isotope decays much more slowly (half-life on the order of one billion years).

      We don't want our country back, we want our country FORWARD. --Eclectablog

      by Samer on Tue Mar 15, 2011 at 02:17:54 PM PDT

      [ Parent ]

  •  Very important discussion (1+ / 0-)
    Recommended by:
    Samer

    Quantity / qualities of radiation are vital pieces of information.  We EAT radioactive materials all the time (e.g. potassium-40 in bananas), and are often surrounded by it (e.g. granite counter-tops containing uranium, thorium, radium and daughter nuclides).  Radiation is natural and our bodies are well accustomed to dealing with it in small / moderate doses.  Some areas have natural background radiation that is up to 100 x's North American average without adverse health effects (30,000+ mrem/year) - I think Ramsar Iran is one notable spot.  So, talking about radiation hazards is pretty much meaningless unless we are including dose and dose rates in the discussion.  This is a very important to consider in light of current events.  

    The intrinsic nature of Power is such that those who seek it most are least qualified to wield it.

    by mojo workin on Tue Mar 15, 2011 at 02:47:41 PM PDT

  •  I am in Tokyo (1+ / 0-)
    Recommended by:
    Samer

    & I find your diary for informative & helpful. We need all the help we can get & good information is very helpful!

  •  US officials cite "paucity of good data" (1+ / 0-)
    Recommended by:
    Samer

    Japanese are sharing very little of the data needed to model the distribution of airborne radioactive particulates and gases, i.e., the plume.

    http://www.cnn.com/...

  •  400 mSv / hr = 40 rem / hr (0+ / 0-)

    I believe the diary may be attempting to quote this figure, i.e. 400 mSv / hr, a measurement from near the Unit 3 reactor building that was widely reported yesterday.  For example, by the IAEA at 15 March 2011, 11:25 UTC:

    http://www.iaea.org/...

    This is 40 rem / hour, or 40,000 mrem / hr, not 400 mrem / hr.  Now the levels have reportedly fallen significantly.

    As an aside, I'll point out that most instruments do not actually measure effective dose equivalent units (rem or Sievert), but measure charge released in some material, e.g. air, and the readings can be subject to interpretive errors. An ion chamber survey instrument that measures roentgens (or coulombs of charge per kg dry air) can be used to estimate whole-body gamma dose equivalent (in rem) by multiplying by a conversion coefficient that, for many common energies of gamma rays, and in the popular understanding, is approximately 1 +/- 20%.  BUT, if you take that ion chamber outside and expose it to beta-emitting fallout, the beta particles will contribute to the measured ionization in a way that is not proportional to their biological effect (which is mostly on the shallow tissues).  It's easy to imagine the measurement of 40 rem / hr being not strictly accurate, or at least being subject to high uncertainty.  However, that's a huge number relative to 400 mrem / hr and was bad news when it came out.  

  •  Alpha emitting particles are extremley (0+ / 0-)

    hazardous, and unfortunately, #3 reactor is apparently using  MOX [mixed oxide], a combination of uranium and plutonium.

    It takes very little plutonium to cause cancer, once it's lodged inside lung tissue.

    Republicans totally abandoned conservatism in the 1980s ..

    by shpilk on Tue Mar 15, 2011 at 05:14:38 PM PDT

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