profile picture

Radiation Detected!

Rainwater and Milk in Oklahoma Radioactive ? Got I-131 ?
May 1st, 2011 11:28 AM

I have been reading various reports in blogs, websites and news reports about radiation levels and increasing levels of Iodine 131 and Plutonium levels in food, air and in food.  By the way, Plutonium has not been found in milk or rainwater!  Some are based in fact, but the time frame is wrong, others are blatant lies and fear mongering trying to sell products that may have some health benefits, but would be of dubious utility when it comes to radiation protection.  I am even hearing radio adds for vitamins touting that we are attacked by radiation on a daily basis!  Ironic that in Oklahoma we are a low background radiation state in most areas.  There are areas that have a relative abundance of radioactive minerals in the soil and exposed geological strata, like the Foss Quadrangle, but for the most part Oklahomans are protected by our relatively low altitude above sea level (thicker atmospheric shielding) and low radon levels statewide (no need for Radon Testing in most Oklahoma homes.) 

This brings us to more reports of high radiation levels at the TEPCO Fukushima Daiichii Nuclear Power Plant in Japan, headlines state "Highest Radiation Levels Detected So Far..." Actually I suspect that these levels have been high all along, and we now are getting to the areas where the high levels can be found via robot.  Some of the areas the robots are going too one in their right mind would not send a human!  That reminds me, there are reports of animals dying in the exclusion zone.  This is not due to radiation as some bloggers have suggested, it is due to improper care.  The poor creatures are not being fed due to an absence of their human care givers.  Even the animals are suffering due to the crisis. 

In the US bloggers are writing about the increases of radioactive materials in Milk and Rainwater.  I personally feel that there is not a not a threat, after all we had much more atmospheric contamination following nuclear testing in the 40's, 50's and 60's following the hundreds of above ground nuclear tests. We didn't have an epidemic of cancer then, and we didn't have mutant babies nor people dropping dead in the streets.  I need to do find some of the archives from that era, there were levels detectable with hand held survey meters, however these archives have been pushed out of the online searches due to the plethora of reports of recent time.  I guess the internet forgets too.

This leaves me to testing, I pulled out the big guns for this, my Ludlum Model 16 and a 1 1/2 inch scintillation probe, My Dosimeter 3700 and a 2 1/2 inch pancake probe, and my Digilert.

The Big Guns




First, I got from the refrigerator a full gallon of milk that was purchased Thursday April 28th, so I was sure that it was of recent vintage.  Since Cesium 137 and Iodine 131 are gamma emitters, I should have had no problem detecting any radiation from concentrations of Cesium 137 and Iodine penetrating the thin plastic container.  Beta particles will easily penetrate plastic as well, and Cesium 137 is a beta emitter as well, so my pancake probe should have no problems measuring anything over background.  The results:

Ludlum Model 16 with Gamma Scintillator probe:

Background = 650 Counts per Second,

Milk, contact with Container = 650 Counts per Second

This was with a slow time response (longer survey setting).  650 Counts Per Second is normal.  Background was the same last summer as well.  Yes 650 Counts per second is 39,000 counts per Minute, the Ludlum with the 1 1/2 inch probe is very sensitive, Much more so than a geiger counter.

I then tried my Dosimeter 3700 with a 2 1/2 inch Pancake Probe.  The pancake, having a larger detector, and there fore more sensitive than the Digilert, came up with the same result:

Background = 40 to 60 CPM

Milk, contact with Container = 40 to 60 CPM

No Radiation levels higher than Background Detected with either instrument, it appears that the Milk is safe.


Did get some interesting results here with the Digilert, and I will explain why I did in a brief moment.  My first task was to collect rainwater from the thunderstorms early this morning, wow, where can I score some rainwater?

My wife's recently waxed black Saturn had some nice rainwater beads all over the shiny black surface.  I could have tried a puddle, but my concern was contamination of the water from Potassium and Phosphate fertilizers I have used on my lawn.  Stable Potassium is always accompanied by radioactive Potassium 40, and most phosphate fertilizers have some Uranium in them, so a puddle would not do.  I got two paper towels, folded them together, and folded them twice.  I then sopped up some of the water on the car and placed the wet towels on a plate (non radioactive of course.)

The Results of the Ludlum:

Background = 650 Counts per Second

Rainwater Swipe = 650 Counts per Second

The Dosimeter 3700 Results:

Background = 40 to 60 CPM

Rainwater Swipe = 40 to 60 CPM

This is where I decided to use my trusty hand held Digilert, with 5 minutes of counts:

Background = 14.6 CPM average

Rainwater Swipe = 16.8 CPM Average

I tested again with similar results:

Background = 14.4 CPM average

Rainwater Swipe = 16.4 CPM Average

This may be definitive.  However is it from Cesium 137 and Iodine 131?

More than likely not.  I may have detected it with the Dosimeter 3700, but the needle like most analog GM counters is a bit bouncy, so a 10% swing may not be noticeable.  Also the Digilert is Digital so small measurements are easier to detect.  The Ludlum did not detect Gamma, and 650 CPS with a slow time constant, a 10% difference is very noticeable.  My best guess is yes, there is some radioactive material in the rainwater I sampled, however it could be attributable to Radon or Radon daughters in the atmosphere, or from normally occurring Radioactive materials found in common outdoor dust.

Unfortunately some of you may feel that it is from Fukushima and we are finally feeling the effects.  Personally I would attribute the higher levels of radiation I found to normal atmospheric phenomenon.  However, I have never tested rainwater prior to Fukushima, so I have no control data.  The jury is up, and if you have any opinion, I welcome you to post to my blog.

PM1703m = 8 ur/hr; Geiger Counter Wristwatch = .12 uSv/hr

Posted in:General
Posted by Chris Cavanaugh on May 1st, 2011 11:28 AMPost a Comment

Subscribe to this blog
I live in the Greater Toronto Area (GTA). Here is my experience I'd like to share we all. I use a wipe detection method to detect the radioactivity in the rain water: I have been detecting fairly high counts of radiation using a regular dish-washing sponge wiped over our cars and solar panels during or right after a rain. I'm measuring typically 1000-2000 cpm with my 2.5" pancake Eberline Geiger counter when the wand is put to the sponge. I estimate the total surface area that is sponge-wiped to be aprox. 6 meters sq. The lowest I've picked up since the beginning of the Fukushinma crisis is 400-600 cpm using this method. The last rain we got on the 6th of May 2011 I measure 3400 cpm, an all time record! I had to us the next scale because the lowest scale would peg the needle on the meter, So I'm definitively observing an increase in radiation. But here is the kicker: The radioactive half life of what is picked up by the sponge is short: I calculate 33-35 minutes. After 10 hours or so, I can't pickup anything above background from the sponge. When the probe is 2 inches from the sponge and I can't pickup anything. Right up against the sponge and it sounds like popcorn frying! Based on this observation, it looks to me it like what is being picked up by the sponge is an Alpha emitter or a weak Beta emmiter. I've looked at all the Uranium and Plutonium decay series and I can't find what radioisotope would match this decay and half-life. Maybe I'm dealing with series of short lived decays with an average totaling 33-35 minutes. The half life is very consistent from rain to rain. I'm guessing what I'm picking up with the sponge is a daughter product of one of the radionuclides transported by the jet stream from Japan. There is no way that what I'm picking up comes directly from Japan, because after 7-8 days in the jetstream, so many 33 minute half lives would have gone by that I doubt I would be picking up anything. It can't be Xenon-133, it's half life is something like 5 days. It doesn't appear to be one of it's daughter products either. Maybe what I am picking up is not from Japan, but from some sort of radioactive cloud seeding tracer used by our "loving" world government. Anyway, I'm perplexed, because this is not a one of event. I'm seeing this every time it rains now. Granted I never thought of checking using this method before Fukushima blew up, but I'm pretty sure that the rain wasn't radioactive before Fukushima. When it rains, I can typically see the background radiation double or even triple to 150 cpm, without using a sponge, just standing in the rain with the probe close to a smooth surface. I hope someone can enlighten me on this one... :o) Syl

Posted by Sylvain on May 11th, 2011 10:14 PM
Hello Sylvain, nice geiger counter and probe. Very interesting results to say the least. However, I find it unlikely that the counts are from Fukushima, but again I am not a scientist, and in true scientific ideology it would be wrong to exclude the possibility that it could be. So is it probable, yes, possible, IMHO no. I would be curious if the cares are driven regularly. If they are you may want to test the air filters after your next drive, even if it is a fair weather day. Here is why. If you are picking up short lived isotopes they are decaying down to virtually nothing above background in rougly a few short hours, it takes days and even weeks for air from Fukushima to get to Toronto, Canada (By the way, nice city!). In general a radioactive substance is considered to be decayed to its stable froms or daughter isotopes and elements after 10 half lives. That leaves us to what you are detecting. I may suggest that you do a TV screen swipe, provided that you have an old CRT style TV. Turn it on for 3 hours, and then test a swipe from that. Even better, if you have an electrostitic air filter like the old Sharper Image Ionic Breeze they can precipitate a lot of gunk and dust from iondoor air. I would suspect that you may be getting similar results on those items as well. The reason for this is from Naturally Occuring Radioactive Materials. Radon can leach out of the soil and geologic formations on days with low barometric pressure, and the daughters can accumulate on most surfaces, expecially those with a static charge like a crt screen. I may suggest trying your automotive air filters, a CRT screen, Open air and finally keep testing the rain, if your schedule allows for it. IF you are concerned contact your province radiological health department, or even better, a local university physics or environmental engineering department. Also I would strongly suggest getting you home tested for Radon, a simple charcoal test is very affordable, and Radon remidation may be something to look into, especially if you ever go to resell your home. I would suggest a local University since they may have a better handle on local geology, and may have alpha spectroscopic equipment to determine what Isotop you are dealing with. IF you are concerned about going to the "Authorities" you may try posting on the CDV700Club Yahoo Groups as well.

Posted by Chris Cavanaugh on May 15th, 2011 8:00 AM
You do realize that you are wrong about beta radiation penetrating plastic, right?

Posted by J.E. McDonald on March 25th, 2012 5:55 PM
Actually higher energy Beta particles will penetrate many plastics, DEPENDING ON ITS THICKNESS. In counts using 1/4 inch aluminum and milk carton plastic, I get a much higher count. However the accepted standard is 1/4 inch of acrylic will block most beta particles. Many isotope holders for beta emmiters are made of plastic. Alpha however, has trouble with most plastics, but will penetrate thin layers of mylar, as long as there are no skin oils contaminating them. If there is something you can share with me that would show that the thin wall of a 1 gallon milk carton would block most beta particles I would like to know... In retrospect the best way to test the milk would be to boil it down, then test the residue. That way a gross count of alpha beta and gamma could be determined.

Posted by Chris Cavanaugh on March 26th, 2012 10:20 AM

Recent Posts:



My Favorite Blogs:

Sites That Link to This Blog: