Impact of changes to International Commission on Radiological Protection models on occupational thorium ore dust intake

Workers involved in mining and processing naturally occurring radioactive materials (NORMs) are potentially exposed to dust containing alpha particle emitters. The objective of this study is to summarize the key impacts of the latest International Commission on Radiological Protection (ICRP) biokinetic model for thorium ore dust intake and to identify model parameters that require further investigation. The dosimetric significance of thorium ore dust exposure has varied widely over time owing to progressive changes in the inhalation dose coefficients. These changes had a significant influence on radiation protection practices in the Western Australian mineral sand industry, including research initiatives and implementation of control measures. Estimated doses to workers exposed to NORM dust have increased because of the most recent ICRP recommendations. Consequently, we highlight the need for future research, especially in relation to appropriate model input parameters specific to the NORM exposure situation and potential studies investigating the health status of past long-term workers.