Radiation sensors in Stockholm have detected higher-than-usual levels of isotopes produced by nuclear fission, probably from somewhere on or near the Baltic Sea, a body running a worldwide network of the sensors said on Friday. The level of isotopes is not considered harmful at this time but the source still needs to be identified.
The Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) oversees a network of hundreds of monitoring stations that use seismic, hydroacoustic and other technology to check for a nuclear weapon test anywhere in the world. That technology can, however, be put to other uses as well.
One of the CTBTO stations scanning the air for radionuclides – telltale radioactive particles that can be carried long distances by the wind – detected unusually high levels of three radionuclides earlier this week: caesium-134, caesium-137 and ruthenium-103.
The Stockholm monitoring station “detected 3isotopes; Cs-134, Cs-137 & Ru-103 associated w/Nuclear fission at higher than usual levels (but not harmful for human health)”, CTBTO chief Lassina Zerbo said on Twitter (here) on Friday evening.
22 /23 June 2020, RN #IMS station SEP63 #Sweden🇸🇪 detected 3isotopes; Cs-134, Cs-137 & Ru-103 associated w/Nuclear fission @ higher[ ] than usual levels (but not harmful for human health). The possible source region in the 72h preceding detection is shown in orange on the map. pic.twitter.com/ZeGsJa21TN
— Lassina Zerbo (@SinaZerbo) June 26, 2020
Zerbo’s post included a borderless map showing where the particles might have come from in the 72 hours before they were detected – a large area (here) covering the tips of Denmark and Norway as well as southern Sweden, much of Finland, Baltic countries and part of western Russia including St Petersburg.
![](http://www.georgiastem.com/wp-content/uploads/2020/06/EbdAa9qXQAYji-z.jpg)
As of June 28, 2020, no countries have laid claim the radioactivity or reported any accidents. We will continue to monitor and keep you updated as details emerge