Possible field screen for better Fukushima rain rad monitoring?

Mark,

Thank you for your comments re my possible field radon screen check for fresh rain samples. As you can see from the above, I have amended my original radon field test of fresh rain water based upon your feedback. Additionally, a possible car swipe method for radiation testing of rain water has been presented.

I am thinking on your comment that at some point geiger measurements of field radiation will be futile. That, "[A]t some point this exercise is futile since a Geiger counter will never allow you to identify the isotopes..."

Yes, I agree that it would provide much useful information to know exactly what kind of isotope is responsible for a measured radiation increase. Yet, if the field radon screen test comes up negative, then at least we know that any increase in radiation above background level is not due to radon artifact. No, we will not know exactly what kind of radiation we are dealing with, but at least we will know we are in the presence of increased radiation due to some external, longer lasting radiation source. Short lived radon is not great to be around at increasing levels, either. But the longer lasting radio nucleides appear to be a much greater health threat due to their longer lasting radio activity (whether at an acute one time hit, or at repeated low level dose exposures over an extended period of time). According to current epidemiological data and recent interpretations that I have read, longer lasting radio nucleides provide greater health risk, when they are inhaled over extended periods of time. Some sternly caution that any internal increases in radiation is unacceptable. Unhappily, compromised health often does not show up until years later after the radiation exposure. Yes, I understand that for most of us, this will not happen. Yet, for some unlucky souls severe health problems will be suffered. None of us unfortunately know, however, exactly whom will be among those unlucky souls.

Well, getting back to our topic, with the knowledge of whether we are dealing with radon versus longer lasting radioactivity, precautions might be put into place; or not.

And to be honest, I now am beginning to wonder if the increased radiation activity since July the 24th, 2011 (whether caused by radon, or not) continues to occur in Los Angeles, perhaps some preventative measures should be taken. (And no, I do not mean potassium iodide therapy; too risky. And, from what I have read, iodide therapy does not appear appropriate to use for continuing low level exposures to radiation.) Unfortunately, I still do not know the exact location of the EPA RadNet Monitoring station in Los Angeles, though some say possibly somewhere in downtown Los Angeles (re the EPA's listed map of monitoring station locations). Where I live in the San Fernando Valley may be an entirely different story from what EPA measurements are showing at the Los Angeles RadNet station. Depending on wind currents, temperature and location (among other variables), radiation levels can significantly change, up or down. And, this can vary even within just a few miles. So, still I am left wondering.

I do not feel that geiger CPM gross beta field measurements are futile. We at least can get some idea of the nature of the activity of the type of radiation we are encountering. Quickly passing radon activity, or longer lasting radio isotopes... Depending upon that differentiating information, we may decide to take, or not to take possible preventative action.

Again, Mark, thanks for your continued support in educating us about radiation. An exhausting task, I am sure. Thanks!

Your comments, Mark, gives me more ideas and questions:

1. Re 4 hour radon final re-test: out in the field, waiting 4 hours may be be very hard for a lot of those folks adventuring about to do. What is the least amount of time that you think would be sufficient in place of the 4 hour mark?
2. Re difficulty of reading freshly obtained rain water samples: maybe a pre-determined amount (if pre-determined amounts are important) of the rain gauge/beaker collected fresh rain water could be poured onto a clean cloth; and then the rain soaked cloth measured by the geiger counter. Do you think that might work better re obtaining successful radiation readings? Then at the 40 minute and at the final re-test stage (if a final later re-test is needed), the same rain soaked cloth could be re-read.
3. Re testing rain swipes on car surfaces: in the discussion of your experiment you indicated that the number of cloth swipes on the rain soaked car surface changes geiger counter radiation readings. More swipes, more radiation. Maybe you could encourage one of the nuclear engineering graduate students to work out a standardized method for field geiger testing of rain water collected off of car surfaces via cloth swipes. Then, that same cloth could be tested for possible radon artifact at the 40 minute screening mark. If the 40 minute re-test comes out negative, there would be no need for the later re-check. Radon screening test result: radon artifact not indicated. If the 40 minute screening test comes back positive (= radiation decay by one half), then once again the same cloth can be final tested at that later re-test time (4 hours, or whatever time you feel sufficient to accurately final test for radon).

I think one of the above just might work measuring rain radiation out in the field. Maybe either one of the above could be used, depending on field circumstances.