The Impact of Human Activities on the Environment
Everything that humans do has some impact on the environment.
Pollution is a result of human activities in the environment. The main
sources of pollution are farming, water pollution and air pollution.
Farming is having an increased impact on the environment. This is
because there is increased pressure on farmers to produce a single
crop and to concentrate on one form of animal husbandry, such as,
dairy cattle or pig breeding. This is more economical because better
use can be made of equipment and organizations such as supermarkets
have fewer farmers to negotiate purchases with. Also transport is much
easier so produce can be easily moved to more distant markets.
Monocultures are produced from this, which are large areas of the same
crop grown on the same land year after year. To improve efficiency
hedges have been removed and this has reduced the amount of habitat
available for wildlife. It has also increased soil erosion. The
removal of hedges increases the area of land available for crops,
destroys the habitat of predators and keeps the number of pests down.
Monocultures are susceptible to pests and large amounts of pesticide
have to be used. Farm animals can produce large quantities of organic
effluent. When this organic effluent gets into aquatic ecosystems it
can cause a rapid growth of algae and plants, which leads to
eutrophication. Other sources of nitrate and phosphate ions such as
sewage and excess fertlilisers can also cause eutrophication. When the
excess algae and plants die the bacteria make them decay severely and
reduce the oxygen content of the water. This leads to the deaths of
many aquatic animals. Biochemical oxygen demand is a measure of the
oxygen removed from the water by bacteria in a given time and is
therefore an indicator of the amount of pollution by organic matter in
water. Pests are organisms that damage or destroy crops and livestock.
There are different types of chemical pesticides for killing different
types of pest. Insecticides kill insect pests, herbicides kill weeds
and fungicides kill disease- causing fungi. Biodegradable pesticides
are broken down by the activities of organisms and only remain in the
environment for short time after they are applied. Non-biodegradable
pesticides cannot be broken down by organisms and remain in the
environment for long periods. Bioaccumulation of non-biodegradable
pesticides happens in food chains and webs.
Some modern farming practices are damaging the environment and the
destruction of habitats reduces the diversity of ecosystems, making
them less stable and farming less sustainable. A balance is needed
between increasing food production and the need for conserving the
environment. Alternative strategies need to be used in order to
achieve this. If...