Test Result on Strontium-90 Detection in Yokohama

Here's the image of the test report by Isotope Research Institute in Yokohama City:

Strontium-90: 195 becquerels/kg

From the same sample, cesium-134 and cesium-137 were also detected earlier.

Cesium-134: 29,775 becquerels/kg
Cesium-137: 33,659 becquerels/kg
Total cesium: 63,434 becquerels/kg

Isotope Research Institute didn't start testing for radioactive strontium until August 20, according to the Institute's website. Thus the time lag.

At the Institute, it costs 65,000 yen (US$847) (pre-tax) to test one sample for strontium-90 (no separate testing for strontium-89), and it takes one week. No volume discount, the webpage says.

The ratio of strontium-90 to cesium-137 in this case is about 0.58%. In comparison, the same ratio from the samples taken in Fukushima Prefecture was between slightly less than 0.1% to 8.2%. In other words, the ratio varies too much to discern any pattern.

Yokohama City has said it is testing for strontium in the sample taken from the same apartment rooftop but with much higher cesium density (105,600Bq/kg total cesium). But remember there was no official announcement about this high cesium detection because "the apartment building is a private property", according to the city. We'll see if Yokohama will announce anything about strontium-90.

The Yokohama Mayor is having her regular Wednesday press conference, but she has refused to let independent journalists including Yasumi Iwakami, who broke the news, attend the press conference. She only wants to deal with the "press club" members.

For my recent posts on strontium-90 in Yokohama City, go here and here.

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