D9.63 – Guidance about exposure scenario: Variability in human and wildlife behaviours and their impact on dose

Radiological exposure of humans and wildlife not only depends on where and to what extent radionuclides are present in the various environmental compartments (the focus of TERRITORIES Work Package 1) but also on the behaviour of humans and wildlife in those environmental compartments. This report discusses the variability in behaviours for humans and wildlife that are the most likely to have the largest impact on the dose received. Radiological assessments for humans have been undertaken for decades and there are many useful data sources describing the most relevant variability in human behaviour. This report focuses on the two pathways that are the most important to dose: external exposure and consumption of local food. For external exposure, the variability in dose is mainly influenced by differences in occupancy in contaminated areas, times spent indoors and outdoors and housing type. For internal exposure, the greatest variability in dose is likely to be related to food consumption rates and the amount of the food consumed that is locally produced. Estimating the dose to wildlife exposed to ionising radiation can be even more complex than for human populations, due to the wide biodiversity and variability between modes of life. This report investigates the different approaches to estimating the total dose that an organism will receive from different exposure routes, accounting for the variability of the relevant parameters. It has been concluded that for wildlife, large variabilities or uncertainties in behaviour do not necessarily translate into a large range in the overall dose received, because the impact of behavioural variabilities or uncertainties most significantly depends on the dominant exposure pathway, which in turn is dependent on the nature of the ionising radiation to which organisms are exposed.