Dynamic modelling of metals - time scales and target loads
Over the past decade steady-state methods have been developed to assess critical loads of metals avoiding long-term risks in view of food quality and eco-toxicological effects on organisms in soils and surface waters. However, dynamic models are needed to estimate the times involved in attaining a certain chemical state in response to input (deposition, fertilizers or manure) scenarios.
Starting from a mass balance, a universal dynamic model was developed by defining appropriate dimensionless quantities, which depend only on the metal under consideration. For any given metal, the model (differential equation) is characterised by the interplay of four (dimensionless) variables: the initial condition, i.e. the concentration at the start of the simulation, the input (driving force), time, and the concentration of the metal at any given point in time. Depending on the question asked, one of these quantities is fixed and the functional relationship between the other three provides the answer.
|Author(s)||Posch M ; Vries W de|
|Publication||Environ Modelling & Software 2009; 24(1):86-95|