Geography Reference
In-Depth Information
ganic matter to an elemental chemical level that makes it suitable for reuse by plants and an-
imals — completing the food chain.
Thus, every food chain may be thought of as a set of linked organic units in which matter is
constantly used and recycled.
The potential for danger
While food chains sustain life in all its forms, they may also pose grave (perhaps fatal) harm when
toxic substances are let loose in the environment. The scenario may easily follow these steps:
1. Toxic waste from a chemical manufacturer enters a lake and taints microscopic forms of
life.
2. Small fish eat the tainted matter and store the harmful stuff in their fatty tissue.
3. Bigger fish eat the smaller fish, and with each meal increase the concentration of toxic mat-
ter in their own fatty tissue, a process call
biological amplification
.
4. Fishermen catch the affected fish, eat them, and so acquire the toxic substance, perhaps
with fatal result if enough contaminated fish are consumed.
Fallout
is another way in which hazardous materials can enter the environment. Fallout is a quaint
term that most folks don't fully appreciate. When a big explosion occurs, a lot of solid matter is in-
stantly pulverized and becomes very fine particles that are thrust into the air. Being so small, they
can remain aloft for a long period until, because they have weight, they “fall out.” Before that hap-
pens, however, wind may “spread the mess” over a wide area. If the explosion involves radioactive
substances, then the fallout will be radioactive in nature. That alone may taint grass that is eaten by
cattle and other livestock. Rainfall, however, may percolate radioactive matter into the soil, where it
is taken up by roots and thus rather thoroughly contaminate the plants.
The Chernobyl disaster provides an instructive real-world case study. On April 26, 1986, a nuclear
power plant in that Ukrainian (then Soviet) city suffered an explosion that resulted in discharge of a
largequantityofradioactive matterintotheatmosphere.Initialattempts bythegovernmenttosquelch
