The Effect of Humans on the Environment

Humans also have an effect on air pollution, as we are the ones who cause most of it. We are filling the air with a number of harmful gases, like exhaust fumes, carbon dioxide, sulphur dioxide and chlorofluorocarbons (C.F.C'S). Our cars give out poisonous gases, which are called exhaust fumes, and they contain lead, carbon monoxide, nitrogen oxides and unburnt hydrocarbons. Cars cause most of our pollution as a huge 60-90% of motor exhaust fumes are let out into our atmosphere.

Carbon dioxide is contributing to the greenhouse effect. This is because it is given off when we burn fossil fuels, like coal and oil, and it is building up over time. Sulphur dioxide is also released when fossil fuels are burnt, but it is more serious as together with the nitrogen oxides in the exhaust fumes, they cause acid rain. These gases can be carries over large distances by winds before coming down either as dry particles or dissolved in the rain. As lakes become acid, fish and small invertebrates die. The acid rain dissolves nutrients in the soil, which are washed out leaving the soil infertile. The rain is killing large numbers of trees and especially conifers.

The C.F.C'S are in the deodorants and spray cans that we use, refrigerators and in making plastic foam. They are also adding to the 'greenhouse effect', and cause the ozone layer to become thin. This layer of ozone in the upper atmosphere protects the Earth from harmful ultraviolet (UV) rays.

Not only does the air get polluted, but also the rivers and seas do as well. Pollutants, like fertilisers, drain from the land into our rivers. Domestic and industrial pollutants are often discharged straight into our rivers. The biggest single pollutant that we have is sewage, and it can encourage the growth of algae and bacteria, which use up lots of oxygen. This leads to the result of many fish and small invertebrates to die.

Our rivers empty out toxic wastes into the sea and this is not a good thing as it causes further pollution, like:

. The fertilisers and sewage encourage the growth of toxic algae

2. Pesticides are becoming concentrated in the tissues of shellfish

3. Radioactive chemicals are found in high concentrations around coastal nuclear power stations

4. Toxic metals, like mercury, copper and lead are going into the sea's food chain.

Oil pollution can be very dangerous and is dealt with in a strict way to try to stop any further damage to the environment. The oil is skimmed or pumped off the sea, but if it doesn't seem to be very effective, then chemicals are used to break the oil down. Oil, if not dealt with, will eventually sink down to the seabed and here it can smother and kill marine animals and plants. As oil is biodegradable there are many microorganisms that can break it down, but this takes a very long period of time to happen. Meantime an improved technique has been used. Oil-polluted areas are 'seeded' with special types of microbes. The complex hydrocarbons making up the crude oil are split into simple, non-polluting compounds.

Some countries in the world create more pollution than others. The reason for this is because they may not have the equipment or facilities to make pollution. Poorer countries do not have many cars or ships and therefore cannot cause exhaust fumes or oil leaks into the sea. In any ecosystem there are environmental and biotic factors to which organisms have to adapt. The impact of human activity on the environment is related to population size, economic factors and industrial requirements and therefore if a country doesn't have one of these factors then pollution cannot be carried out. This is why some countries suffer from more pollution that other ones.

To reduce the problem of pollution there are some suggestions of things that could be done to reduce it, but there are also things that are being done at the moment to try to stop it from happening. Scientists have already developed a type of plastic called Biopol. Microbes in the soil can break this down. ICI (Zeneca) is Britain's largest chemical company and scientists there, put bacteria into fermenters with glucose and other nutrients. The microbes make a chemical that can be turned into Biopol. As plastic is used in packaging and is a major pollutant this is a good idea to get rid of it, although when decomposing Biopol produces carbon dioxide.

Also to help to try and stop pollution:

. People should use public transport more so that fewer vehicles are on the road, and so less pollution is being caused.

2. Aerosol cans should not be used as much, so our ozone layer does not become harmed

3. Our rivers should not be filled with fertilisers or toxic wastes from humans

4. We should burn less of our fossil fuels as when doing this it gives off carbon dioxide, which builds up and adds to the greenhouse effect. Also we should burn less of our fossil fuels as they are very important to us and will soon run out.