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Increasing industrialisation and population density have led to situations where humans and the environment are exposed to a multitude of potential stressors.Often little is known about the mid- and long-term health and ecological consequences of these especially when they occur as mixtures.The consideration of chronic low-level mixed exposures presents considerable challenges for methodology and data interpretation.Determining mixture effects is complex as the contaminants may interact at different levels.Co-contaminants may affect the mobility,absorption,distribution,storage,biotransformation,elimination and evolution of toxic effects of other contaminates.To fully understand the effects of multiple stressors on life-history responses such as growth,reproduction and survival requires challenging experimentation and a multidisciplinary approach.Radionuclides never occur in isolation.Radiation exposure conditions entail a number of radionuclides which are treated in impact and risk assessments in an additive way although considering different weighing factors for different radiation types.However,most if not all,radiological exposure situations are essentially mixed contaminant exposure situations with a mix of radionuclides,heavy metals,metalloids or organic pollutants.We experienced this fact while performing the radiological research at several existing industrially polutted sites.Objective is to research and understand the mechanisms and processes by which mixtures of contaminants interact to induce adverse effects on biota and the environment in order to determine if radiation protection criteria are protective enough when considering a mixed contaminant context.Knowledge on the transfer of pollutants between different environmental compartments,and on the impact of cumulative stressors,including chemical mixtures is to be geathered by developing and using improved assessment tools and novel models,to reduce uncertainty in current risk assessment and screening methodologies,for example by improving the scientific basis for setting safety factors.This will facilitate human and ecosystem health monitoring by providing the link with information concerning the condition of air,water,soil and the built environment.In this context,measurements have to be carried out to analyse the radionuclide content of NORM and the relevant parameters of the exposure pathways which have to be taken into account for both,the employees and the public.The applied measurement strategies must comply with quite diverse radionuclide compositions of NORM and different types of NORM (e.g.scale,bulk material,dust).Further exchange of fast,on site,measurement experiences is desired among the radiation protection experts.