Biouptake modelling factors

KEY FACTORS AND CHALLENGES FOR FUTURE RESEARCH IN BIOUPTAKE MODELLING... 

Modelling biouptake processes helps in the understanding of the key factors involved and their interconnection [1]. In this chapter, uptake is considered in a general sense, without distinction between nutrition or toxicity, in which several elementary processes come together, and among which we highlight diffusion, adsorption and internalisation [2-4], We show how the combination of the equations corresponding with a few elementary physical laws leads to a complex behaviour which can be physically relevant. Some reviews on the subject, from different perspectives, are available in the literature [2,5-7]. 

All of the factors listed in Fig. 9.4 (and many more) could, potentially, influence the spread and biouptake of a metal. A central problem in predictive modeling is to quantitatively rank the importance of such factors and derive models that enable predictions of the y-variable, which in this example represents the metal content in top predator, from as few as easily obtainable and as relevant x-vari-ables as possible. 

In the following simulations, the other sensitivity factors (color, total-P and morphometry) were kept constant and pH varied to simulate effects of limings on the biouptake of the two test substances, Hg and Cs. It is possible to apply a given dimensionless moderator on many rates and model variables. This is schematically illustrated in Fig. 9.6 by the dotted arrow from YpH to the partition coefficient, since the water chemical conditions (pH, alkalinity, etc.) could influence the way metals are bound to carrier particles. 

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