sources of pollution
Pollution is
contamination of Earth’s
environment with
materials that interfere with human
health, the quality of
life, or the natural functioning of ecosystems. Although
some environmental pollution is a result of natural causes
such as volcanic eruptions, most is caused by human
activities. There are two main categories of polluting
materials, or pollutants. Biodegradable pollutants are
materials, such as sewage, that rapidly decompose by
natural processes. These pollutants become a problem when
added to the
environment faster than they can decompose.
Nondegradable pollutants are materials that either do not
decompose or decompose slowly in the natural environment.
Once
contamination occurs, it is difficult or impossible to
remove these pollutants from the environment.