ABSTRACT
The environment contains many chemicals. Fox example, animals and plants themselves comprise vast arrays of organic chemicals in addition to other substances. Chemicals from animals and plants, as well as organic chemicals added to the environment by actions of human society, occur in water, soil, and the atmosphere. These chemicals may undergo
transformation
, which can be defined as any change in the chemical structure of the substance. This could be a rearrangement of the molecule into another form; alternatively, it could be the addition or loss of chemical groups by environmental processes.
