The impact of human activities on the environment

Have a little read: ... 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