Enhanced natural radioactivity in leachate and groundwater of Belgian landfills

To investigate the potential impact on ground- or surface water of natural radionuclides present in waste disposed onto landfills, activity concentrations in leachates, waste water treatment plant discharge and groundwater of several landfills in Belgium have been analysed. 16 currently in operation landfills for hazardous and non-hazardous waste and 10 legacy landfills have been investigated. Results indicate the presence of a slightly enhanced concentration of uranium and other radionuclides in some leachates of landfills in operation. For legacy landfills, enhanced uranium concentration is also observed in some groundwater wells. The presence of uranium in groundwater around landfills is always accompanied by a contamination with other heavy metals and chlorides. No clear linear correlation between concentration of uranium and other metals could be found however. Isotopic ratio between U-238 and U-234 has been calculated in the different water matrices and is close to one in contaminated groundwater, probably indicating an anthropogenic contamination. In all cases, the concentrations of natural radionuclides do not reach values of concern from radiation protection point of view. (authors)