Global 90Sr runoff from Eastern Fennoscandia catchments and water purification estimates

90 Sr runoff amounted to 0.22–0.67% of its budget in the catchment; the value is lower for high-latitude rivers running in the zone of frozen and seasonally frozen grounds. The ecological half-period of a decrease in the 90 Sr concentration in the river water of Eastern Fennoscandia amounted to 5.9–11.5 years in 1979–1985. The lake waters (Lake Ladoga and Lake Päijänne) were renewed approximately 4–5 times faster than the 90Sr content decreased in these lakes.