The statement added that the sample was taken during the period of 9-12 August.
Rosgidromet, the Russian meteorological agency, reported that radiation levels in the vicinity spiked four to 16 times higher than normal background levels.
The Norwegian agency had previously said there was “no health impact” after the brief radiation spike in Russia’s Arkhangelsk region.
“The measurement result is comparable to earlier measurements,” Thursday’s statement said.
“Norwegian monitoring stations detect radioactive iodine about 6-8 times a year and the source is usually unknown. When no other radioactive substances than iodine is detected, the source is most likely releases from production facilities for radioactive pharmaceuticals containing iodine.”
The statement added: “At present it is not possible to determine if the last iodine detection is linked to the accident in Arkhangelsk last week.”