Influence of the Properties of Chemicals on Their Environmental Fate - Organic Pollutants: An Ecotoxicological Perspective - page 67

3 Influence of the

Properties of
Chemicals on Their
Environmental Fate

Chapter 2 was concerned with processes that determine the distribution of chemicals
within living organisms and the relationship between distribution and toxicity. The
importance of properties of chemicals in determining their fate within living organ-
isms was given emphasis. Polarity, molecular size, the presence of functional groups,
and molecular stability were all seen to influence toxicokinetic processes. The types
of enzymes responsible for biotransformations were related to the structures of the
chemicals undergoing biotransformation (e.g., esterases for esters, reductases for
nitro compounds, monooxygenases for aromatic hydrocarbons, etc.). This chapter
will consider the wider question of how the properties of chemicals determine their
fate in the gross environment, and how these properties can be incorporated into
descriptive and predictive models relating to the movement and distribution of envi-
ronmental chemicals.
First, there will be a description of chemical and physical properties that deter-
mine the fate of organic pollutants in the gross environment, restricting the discus-
sion to chemical and physical processes. Next, an account is given of how these data
are incorporated into models that attempt to describe or predict environmental fate.
Finally, the relationship between the properties of chemicals and the operation of
biological processes that determine environmental fate will be discussed. Drawing
on the background given in Chapter 2, emphasis will be given to the relationship
between properties of environmental chemicals and their uptake excretion and
metabolism by living organisms. The overall aim will be to lay a proper foundation
for consideration of the more complex issues in Chapter 4, which will address the
question of movement and distribution of chemicals in ecosystems where both bio-
logical and abiotic processes come into play. Key issues will be the fate of chemicals
in soils and the movement of chemicals along terrestrial and aquatic food chains,
situations in which fate is determined by both biological and chemical processes.

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