Every time building products come into contact with water, substances can be washed out and released into the ground and groundwater as the water drains away. During its passage, substances are exchanged between the ground and seepage water. At the same time, trace substances contained in the water can be degraded by organisms present in the ground. These transformation products usually have different ecological properties than the original material.
To classify the environmental properties of building products, it is essential not only to determine their constituents and potential to leach out but also to model the transport process from the building product to the aquifer. The passage of water through the ground is a critical path. Assumptions for this part of the model have to be validated and calibrated using standardized laboratory procedures.