In the Netherlands, the concentration of radon in most homes and buildings is low. This is due to the composition of the soil. In some special workplaces, such as in limestone caves and at drinking water companies, there may be more radon in the air. Employee exposure to radon can be higher here than in other workplaces. This is evident from research by the RIVM. The Ministry of Social Affairs and Employment (SZW) can determine whether additional measures are needed in these workplaces.
What is Radon?
Radon is a radioactive gas that naturally escapes from the soil and soil materials, such as building materials or groundwater. If a lot of radon escapes and there is insufficient ventilation, the radon concentration in a room can become high. People who are exposed to high radon concentrations for many years have a greater chance of developing lung cancer. This risk is much greater for smokers than for non-smokers.
What has the RIVM investigated?
The RIVM measured radon concentrations in 7 limestone caves in South Limburg and at 65 production stations for drinking water purification. Radon naturally escapes in caves, and there is little ventilation. At production stations, radon is released during water purification. The RIVM compared these measurements with the reference level. Exceeding this concentration should be avoided as much as possible. The RIVM estimated the exposure to radon for employees. The radon concentrations in these areas do not affect visitors to the limestone caves. Tap water is also safe to drink.
What are the results?
In almost all investigated limestone caves, the measured concentrations were higher than the reference level. At drinking water companies, this was the case for about one-third of the measurements. In places with high radon concentrations, employees are usually not present full-time. They may give tours in the caves or come for maintenance at the production stations. Therefore, the exposure of most employees to radon is estimated to be low.
For nearly 30 percent of employees, the exposure is relatively high, meaning higher than it would be if they worked full-time at the reference level. The exposure to radon for these employees is comparable to employees exposed to radiation from other sources, such as hospital staff or pilots.
What can the government do?
European member states must have an action program for radon to minimize health effects as much as possible. The Ministry of Social Affairs and Employment (SZW) can designate workplaces in limestone caves and at drinking water companies as specific workplaces in this action plan. The ministry can then impose measures for these workplaces. If the concentration is higher than the reference level, the employer must take measures to reduce employee exposure to radon.
Why this research?
The RIVM conducted this research at the request of the Ministry of SZW. In 2016, the RIVM first conducted radon measurements in workplaces. It became clear that more research was needed in limestone caves and drinking water stations. This report describes the results. Further research is still possible. Measurements have not yet been conducted at all locations. Research can also still be done on the exposure of individual employees or on reducing exposure.