Tree modeling, pesticide

Some environmental fate processes are not usefully modeled as equilibrium problems because the rate of the reaction is more important to quantify than the final composition of the system. Given enough time, a tree that falls on a forest floor will decompose, a pesticide applied to an agricultural field will degrade, and an open keg of beer will go flat. In such cases, the question of interest is not the final state, but how long it takes to get there—days, years, or centuries. In this chapter, only the kinetics of chemical reactions is presented. Kinetics of chemical transfer between phases is not discussed until subsequent chapters because rates of chemical transfer depend on the specific transport characteristics of the media (as well as on the properties of the chemicals themselves). 

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