Environmental Pathways 13 1—What is Pollution? ?
OVERVIEW
Think about all the things you used or touched
today: water, clothes, carpeting, the plastic
wrapper of a loaf of bread, newspaper, televi-sion
set, a car or school bus, and many others
that make our lives safer, easier, and more
comfortable. Although all these things have
benefits, there are consequences of produc-ing,
using, distributing, and disposing of these
items.
When human activities release harmful sub-stances
into the environment, in quantities or
concentrations that can cause harm to
humans or other living things, the result is
called pollution. Pollution is created, and can
be found in, almost any setting (residential,
industrial, commercial, institutional, and
agricultural) and any type of community
(urban, rural or suburban). These types of pol-lution
are not separate and distinct but affect
each other. For example, pesticide or herbi-cide
applied to farm fields may eventually find
their way into groundwater, while components
of automotive exhaust can combine with mois-ture
in the air and come back to the earth as
acid precipitation.
Although there are many kinds of pollution
(noise, light, radiation to name a few), this
packet will primarily look at air, land and water
pollution. The following background will pro-vide
more information about the movement of
harmful substances in the environment and
the three main types of pollution that impact
the Earth’s closed system.
BACKGROUND
Earth’s Closed System
It may seem to us that things that happened a
long time ago are very foreign to us, or that
we have nothing in common with
people from the past.We know
that people lived in our town
before us, maybe even a long
time before us. But our connec-tion
with the past is greater than
that. You are breathing
the same air and drinking
the same water that your grand-parents,
great-grandparents, the Pilgrims, and
even the dinosaurs breathed and drank!
This is because the Earth is a closed
system. The air that the dinosaurs breathed
did not disappear after they breathed it—the
particles of air came back together and re-entered
the atmosphere to be breathed by
other animals. The water they drank has gone
through the water cycle countless times
before coming to your local well or water
supply.
Earth is sometimes compared to a spaceship.
Aside from the occasional meteorite and
receiving energy from the sun, it does not get
new supplies of water, air or any other sub-stances.
It must rely on and recycle the matter
and energy it has. The basic elements that the
Earth had millions of years ago will still be
here millions of years from now, although per-haps
in a different form.
Cycles, Cycles, & Recycles
Nature uses air, water and land over and over
again. This is nature’s form of recycling.
Energy in the form of sunlight provides the
power for these processes to occur.
The Air (Oxygen) Cycle
No new air is added to the earth. When we
breathe we exhale carbon dioxide. Green
1 What is Pollution?
