POLLUTION
In the mid-1900s, a biologist
named Rachel Carson was afraid that some day there might be no more birds.
Farmers were spraying a chemical called DDT on their fields to kill insects.
But DDT was also keeping birds such as the bald eagle and peregrine falcon from
having babies. DDT prevented the babies from hatching. She wrote a book called Silent
Spring to warn about the dangers of DDT.
Pollution happens when
chemicals that are harmful to living things get into the environment. Rachel
Carson feared that DDT would get into the food people ate. Her book scared a
lot of people. Governments banned the use of DDT. People then began to worry
about other kinds of pollution. They worried that pollution could harm people’s
health.
WHAT DOES POLLUTION DO?
Pollution can kill or
sicken plants, animals, and people. Pollution can change the environment.
Things that cause pollution are called pollutants.
Pollution can get into
the air. Air pollution can irritate people’s lungs. Polluted air can mix with
rain to make acid rain. Acid rain kills trees and harms fish in lakes.
Pollution can also get
into soil and water. From there, pollutants can get into the food chain. Plants
take in the pollution from the ground. Animals that eat the plants can be
harmed, too. Bigger animals and even people might eat the damaged animals.
WHERE DOES POLLUTION COME
FROM?
Air pollution comes from
factories and power plants that burn coal and oil. Smoke from factories and
power plants can mix with water in the air to make acid rain. Air pollution also
comes from cars and other vehicles that burn gasoline.
Soil pollution can come
from chemicals used on farms to kill insects and other pests. Pollutants can
also seep from garbage dumps into the nearby soil and water.
Water pollution comes
from factories that dump poisonous chemicals into lakes and rivers. Water
pollution can also come from farms. Farmers put chemicals on the ground to help
crops grow and to kill insects. Rain can wash these chemicals into lakes and
rivers.
Big ships called oil tankers
can pollute the ocean if the oil leaks out of the tankers. There can be a huge
oil spill if a tanker has an accident and sinks at sea.
A special kind of pollution
comes from nuclear power plants. Nuclear power plants produce radioactive
waste. This waste lasts for thousands of years and can cause cancer and other
deadly illnesses if it is not properly stored.
IS POLLUTION CHANGING EARTH’S
CLIMATE?
Many scientists think
that pollution is changing Earth’s climate. They think the change is coming
from gases in the air called greenhouse gases. Carbon dioxide and other gases
trap heat from the Sun. They trap heat the way glass walls and ceilings in
greenhouses trap heat. It stays warm inside a greenhouse even when it is cold
outside.
Greenhouse gases in the
air make Earth warm enough for life. But scientists think that people are
putting too much carbon dioxide and other greenhouse gases into the air. These
extra greenhouse gases come from burning coal and oil in factories and power
plants. They come from burning gasoline in cars. Too much of them will make
Earth warmer. This warming could cause disastrous changes on the planet.
HOW CAN WE STOP POLLUTION?
Chemicals that cause pollution
are not easy to get rid of. They stay in the air and ground and water for a
long time. The best way to fight pollution is to stop producing it in the first
place. Governments can pass laws that forbid or limit the use of chemicals that
cause pollution. Laws can stop factories from dumping poisonous chemicals in
lakes, rivers, and the ocean. Factories and power plants can clean up the smoke
that they give off.
Engineers can build cars
that burn less gasoline. They can find ways for cars to give off cleaner
exhaust gases.
Scientists are looking
for fuels to replace coal and oil. They are looking for ways to use the power
in wind and in rays from the Sun. They are also looking for safe ways to get
rid of nuclear waste.
You can help cut down
on the amount of garbage you make. You can recycle paper, plastic, glass
bottles, and metal cans. Recycled material gets used over again. Recycling
helps cut down on pollution.
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