The issue of Cs-137 in firewood and biomass combustion: a review.

The article focuses on the regulatory challenges and exposure assessment related to radioactive caesium-137 (Cs-137) contamination in firewood and biomass ashes in Europe following the 1986 Chernobyl accident. It highlights that Cs-137 can concentrate significantly in ashes from biomass combustion, often exceeding the clearance level of 100 Bq per kg defined in the 2013/59/Euratom Basic Safety Standards (BSS) Directive, raising questions about whether such exposure should be regulated as a planned or existing exposure situation. The article compares national regulatory approaches in countries including Finland, Sweden, Norway, and Belgium, noting variations in reference levels and control measures, and reviews dose-assessment studies indicating that public exposure from Cs-137 in biomass ashes is generally low to moderate. Given the increasing use and trade of biomass for energy in Europe, the article underscores the need for harmonized regulations and effective measurement and information transfer to manage Cs-137 contamination in biomass products and their residues.