Water pollution can come from a number of different sources. If the pollution comes from a single source, such as an oil spill, it is called point-source pollution. If the pollution comes from many sources, it is called nonpoint-source pollution.
Most types of pollution affect the immediate area surrounding the source. Sometimes the pollution may affect the environment hundreds of miles away from the source, such as nuclear waste, this is called transboundary pollution.
Surface water Pollution
Surface waters are the natural water resources of the Earth. They are found on the exterior of the Earth’s crust and include:
- Oceans
- Rivers
- Lakes
These waters can become polluted in a number of ways, and this is called surface water pollution.
Oxygen Depletion
Microorganisms that live in water feed on biodegradable substances. When too much biodegradable material is added to water, the number of microorganisms increase and use up the available oxygen. This is called oxygen depletion.
When oxygen levels in the water are depleted, relatively harmless aerobic microorganisms die and anaerobic microorganisms begin to thrive. Some anaerobic microorganisms are harmful to people, animals and the environment, as they produce harmful toxins such as ammonia and sulfides.
Ground Water Pollution
A lot of the Earth’s water is found underground in soil or under rock structures called aquifers. Humans often use aquifers as a means to obtain drinking water, and build wells to access it. When this water becomes polluted it is called groundwater pollution. Groundwater pollution is often caused by pesticide contamination from the soil, this can infect our drinking water and cause huge problems.
Chemical Pollution
Industrial and agricultural work involves the use of many different chemicals that can run-off into water and pollute it.
- Metals and solvents from industrial work can pollute rivers and lakes. These are poisonous to many forms of aquatic life and may slow their development, make them infertile or even result in death.
- Pesticides are used in farming to control weeds, insects and fungi. Run-offs of these pesticides can cause water pollution and poison aquatic life. Subsequently, birds, humans and other animals may be poisoned if they eat infected fish.
- Petroleum is another form of chemical pollutant that usually contaminates water through oil spills when a ship ruptures. Oil spills usually have only a localised affect on wildlife but can spread for miles. The oil can
cause the death of many fish and stick to the feathers of seabirds causing them to lose the ability to fly.
Differernt forms of Pollutions And thier causes can be Found in this useful Link:
No comments:
Post a Comment