Finland says the low concentrations of radioactive material found in air samples pose no danger.

Ruthenium-106, an artificial isotope, was detected in early October and is now gone. European safety officials say it poses no health risk to residents and that it might have come from Russia.

The isotope measured in air in Tromsø for now is unknown. The isotope comes from a nuclear reactor, and is used in medial diagnostic.

Floodwaters in Tomsk region threatens to submerge the river banks in Seversk where highly radioactive liquid waste from the Soviet Union's nuclear weapons program for decades were injected into two unprotected underground reservoirs.