- This data was created based on the survey results at rivers and lakes from the "Monitoring Results of Aquatic Organisms" released to the public in the Ministry of the Environment website.
- In this monitoring, concentrations of radioactive cesium and radioactive strontium in aquatic organisms (aquatic insects, algae, crustacean, shellfish, and fish) in the areas including Fukushima Prefecture were measured.
- The data consisted of measurement results obtained every week from December 2011 to December 2016