Eutrophication is theartificial nutrient enrichment of an aquatic system with organic material orinorganic nutrients, causing an excessive growth of aquatic plant life.Eutrophication is mostly caused by the input of untreated sewage into the riveror lake, the leaching of inorganic fertilisers from agricultural lands and thedischarging of animal waste from farmlands into the lakes, rivers or ponds. Thisprocess induces growth of plants and algae.
This results in a populationexplosion known as an algal bloom. Therefore, eutrophication may cause theoxygen level in the water decreases and danger the other aquatic organism life. Eutrophication is a vital environmental problem since itcauses in a change of water quality and is affect most of the lakes in theworld. In fact, all water bodies are confronted with a slow eutrophicationprocess, but in recent decades has undergone a very rapid progression due tothe various activities by mankind. This process continuously increase in the amountof nutrients, especially phosphorus and nitrogen until it exceeds the naturalconstituent of the water body. Causes of eutrophication Eutrophication is mostly cause by the leaching of thefertilisers from the farming area or the agricultural lands. When thefertilisers at the land are rinsed off by the rain water, they runoff intonearby rivers, lakes, ocean and even the groundwater.
The algae and otheraquatic plant absorb the nutrients and their photosynthesis activity increased.This may result in the dense growth of algae and other aquatic plants in thewater. In addition, the untreated sewage is also one of thefactor that causes eutrophication. Sewage such as human waste from housingarea, chemicals and harmful liquids from industrial area, solid and liquid fromdumping area that are all haven’t undergo sewage treatment are considered asuntreated sewage. In various developing countries, the sewage are illegallydischarged directly into the river that near the housing area or industrialarea.
The waste are then travel along the river into the sea. The waste thatcontain a lot of nutrients contributes to the growth of algae. A huge number ofaquatic animals have died because of the algal bloom causing the imbalanceecosystem development.Also, eutrophication canbe caused by the nature. After a lot of years, the lakes, ponds or river startto accumulate large amount of sediments at the bottom. As the current of waterflow, it tends to wash off the excess nutrients at the land into the water.These sediments are able to absorb large quantities of phosphorus and nitrogen.
And leading to eutrophication in the end. The process of eutrophication Populationexplosion of algae known as algal bloom. This is caused by excess nutrientsdraining into ponds, rivers and lakes. The excessive growth of algae restrictsthe penetration of sunlight into the water. So, the photosynthesis of otheraquatic plant is greatly reduced.
Therefore, the oxygen level in the watergreatly decreases. The algae also grow faster than other organisms in thewater. As a result, most of the algae die without being consumed. Asthe other photosynthetic organisms die and organic material dead plant depositsat the bottom of the water. Decomposing microorganisms especially aerobicbacteria accumulates at the bottom at the lake, decomposing the dead plants,grow rapidly and use up the oxygen in the deeper water. The microorganisms useup the oxygen faster than it can be supplied.
This resulting the biochemicaloxygen demand (B.O.D) increase as the oxygen level greatly decrease. The extremely low level of oxygen killsaquatic animals such as fish and shrimp and most of the aerobic bacteria willnot survive. In extreme cases, the water will becomes completely deoxygenatedas the oxygen level continue to drop. As this time, the anaerobic bacteria willgrow and release toxic gases such as hydrogen sulphide. At high B.O.
D levels,leeches and sludge worms may appear and grow rapidly as they are more tolerantof lower concentration of dissolved oxygen. What is Biochemical Oxygen Demand(B.O.
D)? Biochemical oxygen demand (BOD) isthe amount of dissolved oxygen needed by living organisms to oxidised organicmaterial that is present in a given water sample at certain temperature. Thereare a few variables that are affecting the rate of oxygen consumption: pH,temperature, the presence of certain kinds of microorganisms and the type ofinorganic and organic material in the water. The measurement of B.O.D is anindication of the level of water pollution. Higher level of consumers like fish eat some of the producerlike aquatic plants and the nutrients move up the food chain. When theseconsumers die, microorganisms use oxygen to decompose the organic compounds.So, when eutrophication occurs, the level of oxygen is very low because of thealgae blocking the sunlight to penetrate through the water and causes thephotosynthetic plants die.
No further the oxygen can be produced, aerobicorganisms suffocate and die and oxygen is used to decompose the dead bodies. Atthis point, the B.O.D level in the water is extremely high, therefore the wateris considered as polluted. The higher the B.O.
D, the more rapidly the oxygen isdepleted, the more the water polluted.Solutionsof eutrophication1. CompostingCompostingis the main solution for eutrophication. Eutrophication is mainly begin fromthe use of phosphate and nitrate-rich fertilisers. By practicing composting organic material suchas food residue by burying them in the backyard can actually solve the problem.
The nutrients in the food residue do not contain nitrates and phosphorus thatcause algae to grow, so when there is run-off, it does not causeeutrophication. Same goes to agriculture land or farmland, if the farmers usecomposting as fertiliser for their farms, there will be no run-off that containnitrates and phosphorus. 2. Tightening the laws and regulations against irresponsiblepolluterStrengtheninglaws and regulations against polluter can control the process ofeutrophication. Irresponsible industries, farmers, residence that dischargingharmful material into the river, pond or lake should face a seriousconsequences such as being fined or go to jail.
They should be blamed for their behaviour as they be responsible for theentry of nutrients into the water system and cause eutrophication. The lawsshould aim at enhancing high water quality standards and zero-tolerance to polluter.With the support of policymakers, citizens, pollution regulatory authoritiesand the government, it is easy to control eutrophication. 3.
Reducing Sediment AdditionWhen extra soil get washed into the lake or stream bank,erosion occurs. The extra soil particles will cause the water become cloudy anddeposit at the bottom of the lake. The soil sometimes contain nitrate andphosphorus which contributes to algal bloom.
Steps have to be taken tostabilize the lakeshore or river bank. The most effective technique isshoreline buffer of native plants. 4. Filtration of waste waterWastewater treatment plants, also called sewage treatmentplants or water pollution control plants, remove most pollutants from waste waterfrom any combination of domestic, industrial, commercial or agriculturalactivities, before it is released to local waterways. At the plants, physicaland biological processes closely duplicate how wetlands, rivers, streams andlakes naturally purify water.
Many processes in a wastewater treatment plant are designedto mimic the natural treatment processes that occur in the environment. If notoverloaded, bacteria in the environment will consume organic contaminants,although this will reduce the levels of oxygen in the water and maysignificantly change the overall ecology of the receiving water. Thefore, thenumbers of disease-causing microorganisms are reduced by natural environmentalconditions such as predation or exposure to ultraviolet radiation.