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