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FOCI's Gamma Scout
General News · 12th March 2015
Christian Gronau
There is not much to report on the radiation front - which, of course, is good news.
As you know, FOCI has acquired a small Geiger Counter to be used by interested Cortes residents in an effort to keep tabs on local radiation levels and their changes.
When Maria recently took the Geiger Counter and tested local fish, the readings were zero above background.
My recent measurements of beach kelp produced the same result.
The local environment does not show any evidence, least of all accumulations, of Fukushima-related radioactivity.
An aside about background radiation : radioactivity has always been with us. Indeed, in the geologic past, Earth was much more radioactive than it is today : all living things, including ourselves, lived and evolved with it.
When I first started monitoring radiation levels on Cortes Island (early 2014) the average background reading was 0.08 µSievert per hour (established repeatedly over 24 hour intervals). By July of that year, it had risen to 0.1 µSv/h. At present, it has gone down again to 0.09 µSv/h.
In other words : background radiation values fluctuate, without any clearly identifiable immediate cause. Much of the background radiation is cosmic in origin, with an additional contribution from terrestrial (geological) sources. It is significant, perhaps surprising, considering the granitic nature of our bedrock, that Cortes Island radiation levels are consistently below global average.
A word about fluctuations, for those readers who might have a radiation meter at their disposal or would like to sign-out FOCI's instrument : spot measurements can have surprising and misleading results. Recent momentary (not sustained for more than 30 seconds) values have been bouncing between such extremes as 0.034 µSv/h and 0.164µSv/h !
The larger picture, as reported by Fisheries and Oceans at the end of December 2014, shows that identifiable radioactive isotopes from the 2011 Fukushima disaster have traversed the Pacific Ocean and have reached the continental shelf of BC. Values are predicted to increase until 2016, when they will begin to decline again.
Canadian guidelines allow drinking water to contain as many as 10,000 Becquerel per cubic meter. The Pacific waters are expected to reach a peak concentration of 5 Bq per cubic meter, before dropping down to the traditional value of 1 Bq again. (Please read the last two sentences again : even if you distrust Canadian guidelines and/or test results, the difference between 10,000 and 5 is so great as to accommodate even the most grievous error or fudging of values.)
Our local observations confirm what Fisheries and Oceans have been saying : the aquatic plume, originating at Fukushima, has barely reached the west coast of BC, it has definitely not penetrated any inland waters. Even once it has reached around the north and south ends of Vancouver Island, I doubt very much that our instrumentation will allow us to detect any increase in radiation levels - and even if it did, it would be so minimal as to be of no consequence.
In summation (and side-stepping the confusion of measurement units) : Cortes Island background radiation is less than the global average. Even at the peak of the Fukushima plume, our ocean water might contain one two-thousandth of the radiation allowed for drinking water by the Canadian government.
Good news, then : go eat the local fish (even the wide-ranging salmon), swim in the ocean and, if you must, take that kelp off the beach and into your vegetable garden ...