GIS Based Chemical Fate Modeling: Principles and Applications

Chapter 14

Characterization of Environmental Properties and Processes

Alberto Pistocchi and Dimitar T. Marinov

In this chapter, we discuss the main environmental parameters that are needed to run chemical fate models. For each parameter, we discuss the potentials for data retrieval and the processing needs. Special emphasis is placed on remote sensing techniques and their potential use in spatial modeling of contaminants. We examine how landscape and climate parameters can be used to describe the environmental fate properties and the relevant processes a substance undergoes once released into air, water, or soil.

14.1 Physicochemical Properties and Partition Coefficients

The most commonly used physicochemical properties of organic contaminants include free diffusivity in air and water, octanol–water and air–water partition coefficients, and degradation rates or half-lives in different media. Diffusivities are usually parameterized on the basis of molecular weight and may be considered constant across the environment. In principle, all these properties may be measured in the laboratory, but tend to be very sensitive to environmental conditions, among which, notably, temperature, on which they are all usually assumed to depend.

The air–water partition coefficient, , is usually rather sensitive to temperature. A common approach is to describe it as an exponential function of temperature. ...