Radioactive contamination


Radioactive contamination at Chernobyl, Ukraine © Flickr/Timm Suess

Accidents at nuclear power plants create obvious concerns about exposure of the human population to contamination in the immediate vicinity. There are potentially longer term problems due to the ecological impact from contamination with radionuclides. Radionuclides are radioactive atoms that are either man-made or naturally occurring but only a few are considered to present serious risks to human, wildlife and ecosystem health.

Although many different kinds of radionuclides can be discharged following a major nuclear accident, some are very short-lived and others do not readily transfer into food and ecosystems. Caesium-137 is the primary radionuclide of concern regarding the long-term contamination of forests and forest products, owing to its 30 year half-life.

The transfer of radionuclides in the environment depends on the particular ecosystem. Forests with soils rich in organic matter and generally low in clay content leads to a higher transfer of radiocaesium to most forest products, such as berries or mushrooms. Over time, radioactivity can build up within food, as radionuclides are transferred through soil into crops or animals, or into rivers, lakes and the sea where fish and other seafood could take up the radionuclides. Food collected from the wild, such as mushrooms, berries and game meat, may continue to be a radiological problem for a long time.

After a nuclear accident, monitoring the agricultural, forestry and fisheries environment and restricting the movement and export of possibly contaminated products is an important factor. Preventing wildfires within contaminated areas also remains a high priority since they could release clouds of radioactive particles that still persist in the trees. Smoke from fires can spread thousands of kilometres which could substantially increase the area of impact to humans and the environment.


last updated:  Friday, June 28, 2013