New nationwide survey of radioactive contamination in soil

Norwegian Institute of Bioeconomy Research (NIBIO) and the Norwegian Radiation and Nuclear Safety Authority (DSA) are collaborating on a nationwide survey of soil radioactivity. The survey is part of the environmental monitoring of radioactivity, funded by the Ministry of Climate and Environment.

Radioactive fallout over Norway

The Chernobyl accident in 1986 caused radioactive fallout over large parts of Norway, and radioactive contamination remains in soil in areas that received heavy fallout. Among the substances deposited was caesium-137, which has a physical half-life of 30 years and is still taken up into the food chain. There is also caesium-137 in the soil from atmospheric nuclear weapons tests conducted in the 1950s and 1960s.

After the Chernobyl accident, caesium-137 levels in soil across the country were mapped. This has been followed up with new analyses every ten years — in 1995, 2005, and 2015.

Soil samples to be collected nationwide

In 2025, a new nationwide mapping of caesium-137 in soil will be conducted. NIBIO researcher Paul Eric Aspholm will be responsible for sample collection. By mid-September, he will visit 464 sampling points across the country, from north to south and from east to west. Samples will be collected at the same locations as in previous years to allow for accurate comparison of long-term trends.

The first sampling took place near Bogstadvannet in Oslo last week. From there, the journey continued south to Østfold.

“It’s fantastic to experience our country this way,” says Aspholm, who expects to cover 35,000 kilometres by car over the summer.

He normally works at NIBIO Svanhovd in the Pasvik valley, where NIBIO is co-located with DSA.

Will provide new knowledge

The samples will be prepared and analysed for caesium-137 at DSA’s environmental laboratory.

“The results will provide us with new insights into the long-term development of radioactive contamination and how it varies between different regions,” says senior advisor Runhild Gjelsvik at DSA.

“We’ve seen that the rate at which radioactive caesium disappears from the upper soil layer varies. For instance, earlier surveys show that caesium-137 is washed out more quickly in coastal areas and in Southern Norway compared to areas further inland,” says Gjelsvik.

Radioactive contamination in soil is absorbed by fungi and plants and then transferred to animals that eat them. Although levels have significantly decreased since 1986, the contamination still circulates in nature. Wild products such as reindeer, sheep, freshwater fish, mushrooms, and berries often have higher levels than other food items. Since most people consume only small amounts of such wild foods, this has little impact on the radiation dose to the general population.

Important for nuclear emergancy preparedness

Knowledge of current levels of radioactivity in soil is also important for nuclear emergency preparedness. The data makes it easier to assess the extent and significance of any potential new fallout. Monitoring after the Chernobyl accident has shown that the consequences of nuclear incidents can persist in the environment for decades and has provided valuable knowledge about long-term environmental impacts.