Monitoring radiation in Kona Hawaii

Source:  Monitoring radiation in Kona Hawaii    Tag:  microrem to millirem
As soon as we realized that a half dozen nuclear reactor cores were overheating and melting down in Japan, we turned on our 3 radiation detectors  to see if the radiation was going up here in Kona. We have not given our detectors much attention since moving to Hawaii. Unlike the wide variations in readings we would get on the mainland, the detectors have been consistent here day after day with the same low readings. We knew when we moved to Hawaii that there were no local massive nuclear reactors or nuclear weapons factories. And we knew that wind patterns were favorable for low radiation fallout in case of a disaster elsewhere. However, the extent of damage and ongoing radiation contamination at the Fukoshima nuclear power plant is disturbing.

In Hawaii we are 2200 miles closer to the reactors in Japan than the US mainland and if for some reason the wind blew directly this way (fortunately it rarely does) we might get more concentrated nuclear contamination and a higher dose of radiation.   We are happy that our detectors are showing the normal low levels of background radiation (.016 mREM/hour), so far.

We started monitoring radiation over 20 years ago while living in Los Alamos, New Mexico. When measuring radiation dosage, it’s all about the rate of exposure, in other words, how much radiation and for how long. Fortunately our bodies are capable of and used to repairing the damage from background radiation. The problem occurs when the rate of damage from radiation exceeds our body’s ability to repair itself. OSHA uses REMs (Roentgen Equivalent Man) to quantify radiation exposures. Over the years OSHA has come up with the whole body maximum exposure rate of 1.25 REM over any 3 month period and a total maximum exposure of 5 REM per year.

Dosage is also measured by RAD (Roentgen Absorbed Dose), a measure of the actual amount of radiation absorbed. Sieverts have been promoted by the medical industry because it takes into consideration the volume of the portion of the body exposed and the amount of time of exposure. But in a nuclear disaster like the one in Japan, the distinction is less relevant because every part of the body is getting dosed. Even so, Sieverts are being used to report the dosage to the public. One Sievert (Sv) is equal to 100 REM. To add to the confusion, radiation exposure is also being reported in Grays and nanoGrays, yet another measurement of radiation dose

We created a radiation unit converter Google gadget that allows you to enter in any value and see the values of the other dose units so you can compare them.

Here is what we are finding about the radiation exposure in Japan:
  • Reports from an independent radiation monitoring site on the internet is showing 38 microREM per hour in Tokyo.
  • The IAEA Radiation team took measurements at distances from 56 to 200 km from the Fukushima nuclear power plant on March 20 and they found contamination levels that ranged from 2 to 160 microSieverts per hour. The Nuclear and Industrial Safety Agency said on March 23 that the workers at the Fukushima plant had withdrawn after radiation monitoring showed levels of 500 millisieverts per hour.
  • Our readings in Kona Hawaii range between .005 and .020 mREM per hour.