Geoscience Reference
In-Depth Information
Part II
Properties of Potential Contaminants:
Environmental and Health Hazards
In Part II, we discuss the potential sources, chemical properties, and toxicity of
several major groups of contaminants found in the subsurface environment.
Usually, the release of contaminants to the environment originates from
anthropogenic processes. Even when the contaminants are naturally occurring
species, we often find that human intervention or changes in natural conditions are
involved in the development of pollution. Furthermore, many contaminants are
relatively persistent and therefore may be found in the subsurface environment
long after their actual release.
The massive industrial development that has improved quality of life and
affected the world over the last two centuries has also had a profound impact on
the amounts and types of compounds released into the subsurface. During this
period, many thousands of new materials have been produced, used, stored, and
transported. The amounts of these substances produced, used, and subsequently
discarded have also increased exponentially, leading to the release of huge
amounts of contaminants into the environment. In parallel, the understanding that
many compounds may be toxic or hazardous to ecological systems, in general, and
to humans in particular, has gradually evolved during the last 50 years. This
understanding is dependent largely on complex analytical capabilities: environ-
mental samples contain very low concentration of target substance(s), and such
samples often contain large amounts of interfering compounds.
Part II divides contaminants into two groups: inorganic substances and organic
compounds. The following chapters touch only a small portion of the potential
contaminants that belong to each group; we chose representative materials that
provide a broad view of the subject.
Finally, it should be mentioned that, because other aspects of chemical
interactions and transport of such substances in the subsurface environment are
discussed in other parts of this topic, we focus here on the contamination potential
of these compounds.
