Belgian NORM site

Site Overview

The Belgian NORM site is a calcium difluoride sludge heap from the phosphate industry partly covered with vegetation such as pine trees, birch trees, grasses and shrubs. Radionuclides present at the site, are mainly 238U and its progeny which originate from the phosphate ores. Contamination levels of 226Ra between 2500 and 3500 Bq kg-1 can be found in the soil and sludge together with co-contaminants such as As, Cd, Cr, Pb and Zn. Although remediation measures are planned, approximately 7 ha of this site are available for the next 10 to 15 years to perform long-term radioecological research in a NORM-contaminated terrestrial ecosystem. Since the site is private domain, by agreement with the site owner, permission to access and work there has to be obtained via SCK•CEN ( and a working agreement needs to be signed.

Research activities – Working group Belgian NORM site

Performing research at this site has several added values for the radioecological research community such as:

  • Generating site specific data that can be used to improve and/or validate radiological models
  • Studying long-term effects in non-human biota present on the site
  • Better understanding of underlying processes that determine radionuclide behavior in the environment
  • Comparing laboratory and field data (for transfer, effects in non-human biota, etc.)
  • Using it as a test-site to develop/test sampling and monitoring strategies to improve assessment, remediation and regulation strategies in order to ensure long-term safety of NORM affected sites

To ensure efficiency, continuity and sustainability within radioecological research, a working group related to the Belgian NORM site was created within the EC-project COMET (COordination and iMplementation of a pan-European instrumenT for radioecology) to define common goals and establish joint research actions. As it was only recently decided (2017) to perform research at this site, the initial activities that have been conducted at the site are limited to:

Mapping of gamma-ray dose rate 

 Sampling campaign of upper soil at nine locations to determine the spatial variability of contaminant concentrations

​Initial sampling campaign to determine the distribution of radionuclides between soil (at different depths), tree roots, needles, bark, grasses and moss.


Preparatory activities for on-site monitoring

ALLIANCE partners have further plans for conducting collaborative studies at the site such as:

  • Understanding and modelling the long-term influence of vegetation on radionuclide dispersion in forest ecosystems. As part of the TERRITORIES project (EU-CONCERT funded project), it is intended toset up a plot within the pine trees with equipment to follow the cycling of naturally occurring radionuclides and other elements within the trees, integrated with monitoring of the energy and water cycles. Additionally, it is planned to monitor the radionuclide content within seasonal samples of soil, sludge, tree roots, bark, wood, branches, tree needles and litterfall.
  • Additional sampling campaigns will be set up, using research funds of the partners, to further characterise the site in order to gain more in-depth knowledge of processes determining radionuclide mobility and bioavailability in soil and sludge, and to compare radionuclide behaviour at different NORM sites.
  • The available and generated site specific data will be used to improve and/or validate radiological models.
  • Gathered data and knowledge will be shared between partners ensuring efficiency, continuity and sustainability in radioecological research.

Nathalie Vanhoudt  (
Belgian Nuclear Research Centre (SCK•CEN)
Institute for Environment, Health and Safety
Research Group Biosphere Impact Studies
Boeretang 200, 2400 Mol, BELGIUM