Common Contaminants in Urban Watersheds - Urban Watersheds: Geology, Contamination, and Sustainable Development - page 225

7
Common ContaminantsinUrbanWatersheds
7.1 Introduction
Pollution and contamination are now used synonymously to mean the introduction into the
environment by humans of substances that are harmful or poisonous to human health
and ecosystems (Van der Perk 2006). Over time the term pollution evolved to include not
only substances, but also energy wastes such as heat, light, and noise. Because our concern
in this topic is primarily with chemical substances, we will use the term contamination
throughout.
A chemical or substance becomes a contaminant when it is released into the environ-
ment either inadvertently or improperly—at the wrong place or in the wrong amounts. For
example, milk becomes a contaminant when large quantities are released into a stream.
In urban areas, contaminants are everywhere—in the air, soil, water, inside buildings,
and in our homes. As stated in Chapter 4, most households contain chemicals that would
be considered contaminants if they were released into the environment or disposed of
improperly. These chemicals include the following (Figure 7.1):
• Cleaners
• Solvents
• Gasoline for lawn maintenance, snow removal, and other purposes
• Pesticides
• Herbicides
• Lawn fertilizers
• Some paints
• Oil
• Grease
• Dirt
In addition, the list of common household products shown in the following would
become contaminants if they were improperly disposed:
• Computer equipment
• Televisions
• Some electrical equipment
• Most batteries
• Some building products
• Wood with certain applied preservatives or coatings