"Iodine-131 is a radionuclide with a short half-life (T1/2 = 8.04 day)."
Short half life, a nuclear event of some sort happened recently and nothing has been reported. I-131 is an isotope of Iodine and the source could be natural gas related, medical diagnostic OR a product of uranium and plutonium used in nuclear fission. [0]
Which countries have access to plutonium?
"only particulate iodine was reported."
What is the source of the particles?
"first found during week 2 of January 2017 in northern Norway."
What countries have access to plutonium that are active near Norway?