8287530 Radon at work: exposure levels and determinants in various quebec workplaces

<h3>Objective</h3> Radon is a naturally occurring lung carcinogen, which may infiltrate buildings and expose the occupants, including workers. The objective of this study is to describe radon exposure in various workplaces, to identify factors associated with exposure, and to highlight levers for preventive action. <h3>Material and Methods</h3> Workplaces of targeted sectors (e.g. municipal services, fish farming, groundwater-fed drinking water production, granite finishing) were recruited in four regions of Québec (Canada); two with a high potential for radon emissions and two with a low potential. We included workplaces with an underground or slab-on-grade work area where workers spend ≥ 4 hours per day. Information was collected on building structure, ventilation, water source, occupancy and company operations. Long-term measurements of radon (3 months) were conducted with Alpha Track AT-100 passive dosimeters, which were deployed by the research team in accordance with Health Canada’s Guide for radon measurements in public buildings. <h3>Results</h3> There were 354 radon measurements in 54 workplaces (57 buildings built between 1877 and 2021). There were on average 7 measurements (ranging from 1 to 28) per workplace. The median sampling period was 109 days (range 92-148 days). Ten buildings had all measurements below the detection limit (15 Bq/m³), and six had at least one measurement above 100 Bq/m³. The highest recorded values were above 1500 Bq/m³, in a fish hatchery. Generalized estimating equations revealed that the presence of naturally occurring radioactive material (underground water source) was the most predictive factor for higher concentrations, regardless of the geographical region. The presence of rammed earth rather than concrete foundations was also associated with higher concentrations. <h3>Conclusion</h3> Most workplaces had radon concentrations well below guidelines. Higher concentrations measured in water treatment facilities and in fish farms raise concern about occupational exposures in these workplaces, which may have been overlooked by occupational health authorities.