Pollution indicators - VIRTUAL LEARNING



Water Pollution NotesWater pollution?is the?contamination?of water?bodies (e.g. lakes, rivers, oceans, aquifers and groundwater. This form of pollution occurs when pollutants?are directly or indirectly discharged into?water?bodies without adequate treatment to remove harmful compounds.A pollutant is a substance introduced to the environment that has undesired or harmful effects on a natural resource.Types of water pollutionThere are many types of water pollution because water comes from many sources. Here are a few types of water pollution:1. Nutrients Pollution2. Surface water pollution3. Oxygen Depleting5. Microbiological6. Suspended Matter7. Chemical Water Pollution8. Oil SpillageWater pollutantsIncreasing human population has led to an increase in pollution. Some of this is due to:more fossil fuels being burnt for heat and powermore food being grownland taken over for industry and housing.As a result there has been an increase in levels of water pollution.Nitrate fertilizers are very soluble in water and are easily washed off fields by the rain and then into rivers and reservoirs. Because nitrates are all soluble they cannot easily be removed from the water.Pesticides used by farmers to kill weeds or insects may be washed or blown into streams and rivers.Sulfur dioxide in the air can dissolve in water to form an acidic solution.Pollution indicatorsThe level of pollution in water can be indicated by the species living there. This is known as an?indicator species.Bioaccumulation and Eutrophication BioaccumulationBioaccumulation is when?toxins?build up in a food chain. The animals at the top of the food chain are affected most severely.This is what happens:Small amounts of toxic substances - often from human activity - are taken up by plants.These plants are eaten by primary consumers.The primary consumers are eaten by secondary consumers, and the secondary consumers are eaten by higher level consumers.At each stage (trophic level) of the food chain, harmless substances are excreted but the toxins remain in the tissues of the?organisms?- so the concentration of toxin becomes most concentrated in the body tissues of the animals at the top of the food chain.An?example of bioaccumulation?is the use of?DDT?as an?insecticide?in the 1950s and 1960s. Birds of prey were badly affected because it made the shells of their eggs very thin, causing them to break easily when the birds tried to incubate them.EutrophicationWhen fertilizers are added to farmland in large quantities, plants and animals in nearby rivers and lakes can sometimes be killed, but not by poisoning. The steps in eutrophication are quite complicated.Effects of Water PollutionThe effects of water pollution are varied and depend on what chemicals are dumped and in which locations.Many water bodies near urban areas (cities and towns) are highly polluted. This is the result of both garbage dumped by individuals and dangerous chemicals legally or illegally dumped by manufacturing industries, health centers, schools and market places.Death of aquatic (water) animalsThe main problem caused by water pollution is that it kills life that depends on these water bodies. Dead fish, crabs, birds and sea gulls, dolphins, and many other animals often wind up on beaches, killed by pollutants in their habitat (living environment).Disruption of food-chainsPollution disrupts the natural?food chain?as well. Pollutants such as lead and cadmium are eaten by tiny animals. Later, these animals are consumed by fish and shellfish, and the food chain continues to be disrupted at all higher levels. DiseasesEventually, humans are affected by this process as well. People can get diseases such as hepatitis by eating seafood that has been poisoned. In many poor nations, there is always outbreak of cholera and diseases as a result of poor drinking water treatment from contaminated waters.Destruction of ecosystemsEcosystems?(the interaction of living things in a place, depending on each other for life) can be severely changed or destroyed by water pollution. Many areas are now being affected by careless human pollution, and this pollution is coming back to hurt humans in many ways.Prevention of water pollution.Dealing with water pollution is something that everyone (including governments and local councils) needs to get involved with. Here are a few things you can do to help. Learning about the issue (like you are doing) is the greatest and most important step to take. Here are a few more:You can help!!!Never throw rubbish away anyhow. Always look for the correct waste bin. If there is none around, please take it home and put it in your trash can. This includes places like the beach, riverside and water bodies. Use water wisely. Do not keep the tap running when not in use. Also, you can reduce the amount of water you use in washing and bathing. If we all do this, we can significantly prevent water shortages and reduce the amount of dirty water that needs treatment.Do not throw chemicals, oils, paints and medicines down the sink drain, or the toilet. In many cities, your local environment office can help with the disposal of medicines and chemicals. Check with your local authorities if there is a chemical disposal plan for local residents.Buy more environmentally safe cleaning liquids for use at home and other public places. They are less dangerous to the environment.If you use chemicals and pesticides for your gardens and farms, be mindful not to overuse pesticides and fertilizers. This will reduce runoffs of the chemical into nearby water sources. Start looking at options of composting?and using organic manure instead.If you live close to a water body, try to plant lots of trees and flowers around your home, so that when it rains, chemicals from your home does not easily drain into the water. ................
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