The session aims at collecting contributions from all scientists daily faced with the need of discriminating between what is natural and what is the result of the interaction of humans with the surrounding environment, with respect to elemental concentrations. Commonly, geoscientists involved in environmental projects are requested to define local or regional reference concentration values for those chemical substances (mostly potentially harmful elements) and, recently, radioisotopes which can be originating from both geological materials and human driven processes.
To discriminate natural contributions from anthropogenic ones is a very complicated task and several scientists have applied different methods and multiple approaches (from statistics to the weight of evidence) in order to provide guidance and reliable solutions to government institutions and professional stakeholders.
Case studies on solid matrices (soil, sediments, etc.), natural water and other environmental media are of interest for the session together with more methodological studies mostly focusing on the proposal of innovative techniques for defining these values.