OUR ENVIRONMENT
HOW
DO OUR ACTIVITIES AFFECT THE ENVIRONMENT?
-
Ozone (O3) is a deadly poison. However, at the higher levels of the atmosphere,
ozone shields the earth surface from dangerous ultraviolet (UV)
radiation from the Sun. UV radiation causes harmful effects such as skin
cancer.
-
At the higher levels of
the atmosphere, the higher energy UV radiations split some O2 into
free oxygen (O) atoms. They combine with O2 to form ozone (O3).
O2
O + O2 → O3
-
In 1980s, the amount of
ozone began to drop sharply. It was due to chemicals like chlorofluorocarbons
(CFCs) which are used as refrigerants and in fire extinguishers.
-
In 1987, the United
Nations Environment Programme (UNEP) made an agreement to freeze CFC
production at 1986 level. It is now mandatory to make CFC-free refrigerators.
-
Other
ozone depleting substances: Hydrofluorocarbons
(HFCs), halons etc.
-
The size of the ozone hole
has reduced in recent years.
Managing the
Garbage we Produce
-
Garbage are the unwanted
materials that people have thrown away.
-
In organisms, specific enzymes
are needed to break-down a particular substance. So, if we eat coal, we do not
get energy. Similarly, bacteria or other saprophytes have no enzymes to break down artificial materials like
plastics.
-
Substances that are
broken down by biological processes are called biodegradable. E.g.
Fruits, vegetables, leaves, meat, paper, rubber etc.
-
Substances that are not
broken down by biological processes are called non-biodegradable. They are
inert and persist for a long time or may harm the ecosystem. E.g. Plastics,
glass, nylon etc.
|
Non-biodegradable
substances |
Average
time to break down |
|
Glass
bottle |
500
years |
|
Plastic
bags |
10-20
years |
|
Plastic
container |
50-80
years |
|
Plastic
soda bottle |
450
years |
|
Nylon
fabric |
30-40
years |
-
There are biodegradable
plastics such as Polylactic acid, Polyhydroxyalkanoates, Polybutylene
succinate etc.
-
At home and class room,
there are various biodegradable and non-biodegradable wastes produced. They
have to be collected separately and treated properly.
-
The local body (panchayat,
municipal corporation, resident welfare association) have mechanisms to treat
biodegradable & nonbiodegradable wastes separately.
-
Improvements in
life-style and changes in attitude have generated much amount of waste
material.
-
Changes in packaging have
resulted in much of our waste becoming nonbiodegradable.
Disposable
cups in trains
- Disposable plastic cups are non-biodegradable. An alternative
was kulhads, (disposable clay cups). But making these result in the loss
of the fertile top-soil. Now disposable paper-cups are used. It is better than
plastic cups because it is biodegradable and do not affect the property of
drinks in the cup.
Electronic & electrical wastes (e-wastes) include mobile phones, computers, televisions etc. They contain dangerous chemicals such as mercury, lead, cadmium, polybrominated flame retardants, barium and lithium. They cause damage to brain, heart, liver, kidney and skeletal system.
