the human population grows, more and more planting must be done to sustain them. As a result of this measures have been taken
by agriculturalists to maximize the production of foodstuffs. To make sure that they dont waste their time after they have
planted the now produce, they spray them with chemicals to keep rodents away from the crops. They either use pesticides or
insecticides to kill and deter weeds, fungi, and rodents. When these chemicals are sprayed on the crops, it sinks into them
and the plants grow absorbing them and then when we eat them, we have the chance of falling ill or getting all kinds of illnesses
like cancer and birth defects. Some of these pesticides also move through the air and then and inhaled. Because pesticides
and insecticides are made to resist rain and some rodents have developed a genetic resistance for these chemicals, farmers
use more than they should and it stays in the atmosphere for a longer period of time. Some of these have brought about devastation
and other forms of pollution to the environment. When the topsoil is washed away, it sometimes gets into streams and rivers
and causes dirt to get into our drinking water.
some urban areas, they are experiencing a problem with the disposal of garbage and other kinds of waste that can be hazardous
to their health such as some solvents (Lead sulphate) and other industrial waste that can get into our drinking streams. So
they dispose off their garbage and other waste where they think is appropriate for them and they get into the drinking streams
and the soil, then into the body and they fall sick and some of them even die. Instead of doing this, they could recycle their
waste and live in a healthier environment.
heavy metals are copper, lead, mercury and selenium. They get into water bodies and from industrial waste, car exhaust, mines
and from soil. Also, animals drink from these water bodies and then get contaminated and it gets passed on to us the end consumers.
These metals are harmful to the body and when they pile up, contaminate the body and then become poisonous causing sickness
or long-term health problems. Taking cadmium into account, it is derived from sewage sludge can be absorbed by crops and it
can cause diarrhoea and even over time liver and kidney problems. Lead, another poisonous metal, gets into our drinking water
from the solder in the water systems and it causes mental retardation in children.
are waste chemicals that are either poisonous, capable of producing explosive or toxic gas, capable of corroding steel or
flammable. These wastes always get into our water streams through improper dispose off waste by industries and other companies.
In 1969 the Cuyahoga River in Cleveland, Ohio, was so polluted with hazardous wastes that it caught fire and burned.
sometimes turn waterways into open sewers by dumping oils, toxic chemicals, and other harmful industrial wastes into them.
In mining and oil-drilling operations, corrosive acid wastes are poured into the water. In recent years, municipal waste treatment
plants have been built to contend with water contamination. Some towns, however, still foul streams by pouring raw sewage
into them. Septic tanks and cesspools, used where sewers are not available, may also pollute the groundwater and adjacent
streams, sometimes with disease-causing organisms. Even the purified effluent from sewage plants can cause water pollution
if it contains high concentrations of nitrogen and phosphorus. Farm fertilizers in some regions fill groundwater with nitrates,
making the water unfit to drink. Agricultural runoff containing dangerous pesticides and the oil, grime, and chemicals used
to melt ice from city streets also pollute waterways.
and pesticides is another major source of pollution. These are the chemicals, such as chlordane and dichlorodiphenyltrichloroethane
(DDT) used by the farmers to kill unwanted animals on their farms. The animals feed on the plants with the chemicals and then
die. Other animals feed on the plants and live. Now, the ones that live get contaminated and then pass the chemicals that
have got into their tissues and other parts of their bodies, on to the next consumer.
a time, these chemicals gather or get into our drinking sources, through rainfalls and erosion, and then the water is contaminated.
Also, when the chemicals get into the rivers and other sources of life for animals that live in water, they consume the water
and then they get contaminated with these chemicals. So then, any consumer who eats the fish also gets affected by the contaminated
fish or whatever animal it is. Oxygen levels in the water may drop to such dangerously low levels that oxygen-dependent animals
in the water, such as fish, die. This process of depleting oxygen to deadly levels is called eutrophication.
of the land that feed on the crops that have been sprayed with the chemicals also get contaminated and the end consumers,
which are us human beings, gets polluted and affected. These chemicals can cause birth defects and cancer, when they get into
SPILLS AND PETROLEUM PRODUCTS
spills are another form of water pollution. Ships that travel with oil and other products derived from oil that are used as
fuels, lubricants, plastics and other purposes, at times spill oil into the sea accidentally. On the French coast, in 1978,
the tanker Amoco Cadiz and the Exxon Valdez in Alaska in 1992 got wrecked. This becomes a think layer on the surface of the
water and then prevents oxygen getting into the water and carbon dioxide from coming out. Because most petroleum products
are poisonous, the fish get contaminated with chemicals such as polychlorinated biphenyls (PCBs).
and deliberate discharges, when tanks are flushed out with seawater, also add a lot of oil to the oceans. Offshore oil platforms
also produce spills: The second largest oil spill on record was in the Gulf of Mexico in 1979 when the Ixtoc1 well spilled
530 million litres (140 million gallons). The largest oil spill ever was the result of an act of war. During the Gulf War
of 1991, Iraqi forces destroyed eight tankers and onshore terminals in Kuwait, releasing a record 910 million litres (240
million gallons). An oil spill has its worst effects when the oil slick encounters a shoreline. Oil in coastal waters kills
tide pool life and harms birds and marine mammals by causing feathers and fur to lose their natural waterproof quality, which
causes the animals to drown or die of cold. Additionally, these animals can become sick or poisoned when they swallow the
oil while preening (grooming their feathers or fur).