Maps as tools to visualise cumulative risks of pollutants

Geographical risk maps provide a powerful tool for visualisation of the spatial distribution of environmental stressors and their effects on human health and ecosystems. There are many different types of such maps. One important distinction is the one between maps that simply show the geographical distribution of stressors and ‘true’ risk maps that also show the consequences. One may also map the vulnerability of areas to pollution, i.e., before pollution actually occurs. Traditionally, risk and vulnerability maps display the information for single stressors or pollutants, whereas in the real world people, animals and plants are exposed to a multitude of polluting substances and stressors at the same time. During the NoMiracle project in the past five years, novel methods have been developed for cumulative risk assessment and also for the mapping of cumulative effects of environmental contaminants, both in the area of human health risk assessment and ecological risk assessment. Examples of these maps, both from the project and from other sources, will be shown along with information on how they were made and how they can be used. One very important objective of risk maps is often to communicate the results of environmental risk assessment to stakeholders and to the general audience. However, this should be done both with great care and in a scientifically sound manner. For example, suggestive use of symbols and colours needs to be avoided. Proper risk mapping, therefore, requires a certain level of expertise in risk communication as well. A list of some general rules of thumb for making appropriate risk maps, taking into account these principles, will be presented