Lethal Exposures / Absorptions / Ingestions of Cesium-137?

I am not trying to be a doomsayer, scaremonger or Chicken Little. Honestly, I'm not. There are a few things I'm struggling to understand here, and, frankly, trying to on my own, a totally unqualified former liberal arts major who made a C- in college Chemistry, is scaring the living daylights out of me. I could really use some TRULY "expert" input, here, because I'm frankly adding up two and two and coming up with potentially lethal doses of C-137 for ALL OF US in the quite near future if radioactivity levels remain pretty much where they are now.

Please try and follow my (hopefully massively flawed) logic and, if possible, give me some peace of mind. (One of my major frustrations is that there is a real dearth of SPECIFIC, INFORMATIVE, RELIABLE data from anything approaching responsible persons or bodies, including in the U.S. Government (to say nothing of the inconsistencies, platitudes and vapid reassurances that have been the Japanese government's and TEPCO's modus operandi these last several weeks).

OK. Let's assume that the most recently tested / monitored / verified C-137 levels, across ALL delivery systems (air, rainwater, and milk), published by the Berkeley Lab (and I simply cannot tell you how relieved I am to have access to the results of your continued efforts -- bless you), are not only accurate, but represent a reliable "mean" for the entire continental U.S. for the foreseeable future. (Clearly, this is a big assumption, and inaccurate to boot -- since Berkeley's results will likely not be the same as Las Vegas's, or Denver's, or St. Louis's, or Dallas's -- which is the "big city" I live nearest to. Also, there is no real reason to suspect that ANY "trend" extrapolated from your data will hold -- if there's ANY such "trend", at the moment, it's that daily -- even hourly -- results are pretty unpredictable, though it does not seem likely for the moment that C-137 is going to simply disappear from the environment altogether. But I am unable to find reliable data for Dallas, beyond fairly generic estimations of beta radiation gross count rates, and thoroughly undecipherable gamma radiation gross count rates, broken up into ten different -- but unlabeled -- strata. ...I've been referring to the EPA's RADNET online resources, btw, found at: http://www.epa.gov/japan2011/rert/radnet-dallas-bg.html.)

Anyway. So, as I understand it, here's what we're looking at (for the most recent dates for which data is available, March 27 through March 30):

Air Sample of March 29: 0.00000018 Bq/L.

Rain Water Sample of March 27: 0.46 Bq/L.

Milk Sampling by the Berkeley Lab has so far been unable to produce measurable levels of C-137, so, I'll be applying the same ratio cited regarding the levels of Iodine-131 currently being reflected in milk versus tap water and rainwater - therefore, (eventual) levels of C-137 in milk will be estimated to be 3:1 versus rain water, or 1.38 Bq/L (based on the March 27 appraisal of C-137 at 0.46 Bq/L in rain water).

Tap Water sampling by the Berkeley Lab has also so far been unable to produce measurable levels of C-137 -- but, as with milk, we all know it's going to show up at some point, so, I'll be applying the same ratio cited regarding the levels of Iodine-131 being reflected in milk versus tap water and rain water -- therefore, (eventual) levels of C-137 in tap water will be estimated to be 1:500 versus rain water, or, 0.00092 Bq/L (based on the March 27 appraisal of C-137 at 0.46 Bq/L in rainwater).

Here's my reasoning: I believe I'm correct when I say that what's in the rainwater NOW will necessarily -- by definition, really -- "trickle down" to reservoirs, groundwater and wells at some point in the undefined, but likely not-too-distant, future. (I am ignoring for the moment the reality of the situation, too, that eventual C-137 concentrations will AGGREGATE, and therefore will be more properly estimated as a CUMULATIVE FIGURE, and not an average or mean like I have made allowance for here. Therefore, I'm going to assume that -- again, pretty much by definition -- the current rate at which Iodine-131 is being measured in municipal water supplies will NOT remain at "a factor of approximately 500" lower than that found in rainwater -- concentrations will become elevated as saturation occurs and solubility increases, perhaps exponentially as our exposure to radionuclide plumes from Honshu continue into the unforeseen future. And, of course, I am conveniently ignoring the fact that processed milk products, such as cheeses, creamer, half-and-half, and a myriad other food products, will necessarily present far HIGHER concentrations of C-137, rendering those items perhaps orders of magnitude more dangerous than milk in and of itself.)

...So, here, then, is my question / horror:

As I understand it, the danger of C-137 is deceptively profound. In very small, even minuscule, quantities, it is highly unlikely to cause serious harm. However, its true lethality is very much a function of its AGGREGATION -- in quantities of water, in food, and, most perilously, in the human body, which is manifestly UNABLE to expel C-137 (except in cases where Prussian Blue has been administered in a timely fashion, which is clearly NOT taking place -- or even being seriously discussed, insofar as I can tell -- here in the U.S., or, for that matter, anywhere, more's the pity). I believe I understand the Berkeley Lab's calculations regarding the amount of years breathing air so contaminated -- 4000 or so, in this case -- numbers of liters necessary for consumption, etc., before, as your methodology states, one would reasonably expect to absorb a dosage of 0.05 mSv... As you say, roughly equivalent to the amount of radiation the human body would be exposed to during the course of a transcontinental flight. Such comparisons, at first, appear to be highly reassuring... A cross-country flight doesn't sound so bad, right?

...But right there's the problem, because, according to a 1972 study that examined the effect of injected C-137 in small dogs, a dose of merely 3800 ?Ci/kg is absolutely LETHAL to beagles -- within three weeks, no less. Assuming that the average adult human is, say, five to ten times the mass of a fully-grown beagle, one would infer that a breathtakingly lethal dose to a human being would require no more than 38,000 ?Ci/kg.

Let me see if I have the conversions right -- this may be easy for Berkeley scientists, but for me, it's like translating English into Latin, then Greek, and finally Sanskrit:

38,000 ?Ci = 1,406,000,000 Bq?
...and,
1 liter = (roughly) 1 kg?

Is that right? Sorry, remember, I was a liberal arts major (twenty years ago, no less, and at Texas A&M -- which is a little like studying psychiatry at DeVry).

Assuming I'm in the ballpark, then, there we are -- and I would assume that although a pretty much INSTANTANEOUSLY lethal dose of C-137 (for adult humans) would be somewhere north of 140,600,000 Bq, it wouldn't be a great thing in much, much smaller concentrations -- particularly to children, the elderly, pregnant women (and their unborn children), and the immuno-compromised. (Interestingly, for all my searching online, I'm just not able to find ANYTHING in the way of specifics regarding the probable effects of C-137 exposure -- perhaps because there just hasn't been a whole heckuva lot of documented "research" into such a phenomenon, seeing as C-137 has only ever been released IN QUANTITY into the environment a handful of times in the history of the planet.

Getting back to the transatlantic flight: 0.05 mSv doesn't sound all that dangerous, until you do the conversions...

0.05 mSv = 0.00005 Bq... right?

...Aren't we, all of us, ALREADY looking at significant exposures, then, with every single gallon of milk we drink... Not to mention, what's likely to show up in far, far HIGHER concentrations, in, not only cheese, but, say, Alaskan King Crab? Or saltwater Pacific Ocean fish? Or vegetables and fruits that not only get irrigated and sprayed by municipal, well, and reservoir water, but get rained on, washed, etc.?

...I don't know. Have I got it all wrong? Are we TRULY "safe"? Can anyone with knowledge -- I readily admit, I have none, and only the barest understanding of what we're talking about, here -- help me understand why we're not in mortal danger, perhaps not IMMEDIATELY, but certainly in the AGGREGATE?

I apologize if my questions and suppositions are stupid... I have tried to inform myself the best I can, but this isn't exactly the sort of information that the general public has the ability to comprehend, and the government's done a frankly TERRIBLE job of making any of this explicable. I appreciate any input, and will gladly take any abuse or mocking. I WANT to be wrong.

Many thanks in advance -- Again, THANK YOU for the work you are doing, and for making it so accessible to we non-scientific minds.

R. Cromack
Allen, Texas
www.facebook.com/lonestarplano