Source-path-target With respect to criteria setting, the environmental risks of the release of constituents from (building) materials can be summarized in two steps: (1) the release itself ("source term", which is a function of chemical reaction and transport processes) and (2) impact scenario (transport of a constituent towards a receptor). The source term can be assessed directly by the results from leaching test methods.
There are several different application scenarios, but with largely the same questions: What are the total released amounts, what are the peak concentrations and (how) does a contaminant reach a certain "point of compliance" (grey arrows)? For impact on soil and groundwater, the total released amounts are often of interest due to regulations. For ground water, and peak concentrations are also of interest.
