Acid Rain

U.S. Dept. of the Interior
National Park Service
.
.

Spanning the Gap
Acid Rain
The newsletter of
Delaware Water Gap National
Recreation Area
Vol. 10 No. 2 Summer 1988
Acid rain is rain or any form of precipitation (snow,
hail, fog, etc.) which mixes with pollutants to give it a
more acidic nature than water. Acid rain is caused
by pollutants in the air that mix with the water
molecules to form acids, rather than water droplets.
The pollutants come from many different sources;
however, emissions from power plants and
automobile exhaust are the main offenders.

Trout in a pond on the
We need to be concerned about acid rain because
Pennsylvania side of the park.
of the low pH value of the rain today. On average,
the pH of the rain in the Delaware Water Gap
National Recreation Area is 4.5, which is ten times
more acidic than "normal".
pH Scale
pH Scale
Acid rain is measured on a pH
scale. The scale tells us
whether a substance is acidic
or basic.
The scale ranges from 1 to

14; 1 being the most acidic, 7
is neutral and 14 is the most
Once you know how acidity is measured (See explanation at
basic or alkaline. A one step
right), and you learn that "normal" even "normal" rain is acidic,
move in any direction is
you might think: what are we worried about?
multiplied by ten.
The effect of acid rain on humans has not yet been discovered
For example, coca-cola has a
but many of the effects on natural features are known. For
pH of 4.5 and "normal" rainfall
example, when a body of water becomes more acidic, it
has a pH of 5.5. The cola is
dissolves more aluminum and other metals, which are toxic to
10 times more acidic that the
fish (and humans!) One of the most noticeable effect acid rain
water. Another example:
has had on the environment is in the lakes in New York's
lemon juice has a pH of 2.2
Adirondack Mountains, which have been acidified to a point
and tomatoes have a pH of
where fish life often cannot survive. Acid rain also affects the
4.2 a two step difference.
built environment by eroding paint and metals on buildings and

---

monuments.
This means that the lemon
juice is 100 times more acidic
The recreation area is very aware of the effects acid rain could
than the tomatoes.
have on both natural and cultural resources within the park.
Currently several research projects in the park are devoted to
acid rain. Some effects of acid rain have already been
detected, especially in some of the lakes on the New Jersey
side of the park. One research project has concluded that acid
rain was responsible for the nearly complete failure of rainbow
trout reproduction in 1984 in Van Campens Brook in New
Jersey.
Solutions are available to help stop acid rain. Industries can
invest in scrubbers, which breakdown the emissions so acid
rain won't form. People, too, can have an impact by reducing
automobile travel through walking, riding a bike, or carpooling
to work.

Van Campens Brook NJ.

---