GIS Based Chemical Fate Modeling: Principles and Applications

Chapter 13

Retrieval and Analysis of Emission Data

13.1 Characterization of emissions

Chemical emissions are a key input to models. However, only for a few chemicals can we rely on accurate estimates of emissions at the global or regional scale. The availability of information on chemical emissions varies greatly among countries and areas of the world, and so does the length of the track record of substances, which raises concerns for their environmental impact.

Chemical fate and transport models are designed to cope with mass delivered to a specific medium. The mode of entry of a chemical into the environment may critically affect its fate. Identifying a mode of entry requires understanding in which phases and media the substance is likely to enter first. For instance, if a plant protection product is released to the soil in solid form, it may be considered as emitted to the soil compartment and may undergo processes in the soil, including soil phase partitioning, washout, erosion, volatilization, and degradation; its solubility and affinity for organic matter will then play a key role as well as the soil organic carbon content. The same substance sprayed over the soil might volatilize immediately to the atmosphere, being basically unaffected by the properties of the underlying soil.

For most chemical substances, emissions are basically unknown and require estimates. Most of the times, the generation of emissions for a chemical fate and transport model is a modeling exercise in ...