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RESTORATION AND RECOVERY OF LAKES - NOT JUST PREACHING BUT PRACTISING
L.Bharath
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INTRODUCTION
POLLUTION IN LAKES
LAKE CONSTANCE
CLEAR LAKE, CALIFORNIA
PREVENTION
CONCLUSION
| INTRODUCTION: |
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Pollution! Pollution! Everywhere! It has indeed become a nightmare these days. This infamous word has become a household name like any popular brand of soap or shoe. Ten years ago, very few people might have had a vague idea of what pollution was all about. But today, everyone knows the exact definition of pollution. They define it as a phenomenon that contaminates Mother Earth with something poisonous and harmful, which in turn affects the health of the inhabitants of this ecosystem. The word "pollution" has started haunting people, initiating serious discussions in various forums. It is one of the most serious problems faced by the world today. Although, the plan of trying to stop this mammoth blunder from causing further destruction has been in every politician's agenda for more than a decade, so far no "serious and concentrated" attempt has been made.
The presence of a lake adds beauty to a place. A calm lake bordered by beautiful trees is a place next best to paradise. To human beings and animals, it is one of the most important sources of fresh water. It is also a source of drinking water for the people. Lakes support large ecosystems. The rich soil helps in the growth of aquatic plants. These aquatic plants attract tiny organisms, which in turn are eaten by fishes. And talking about fishes, they provide food among other things. If a lake has rich animal life, it will make a home for the migratory birds including common birds like ducks, swans and cormorants. Thus, they help in maintaining and protecting the biodiversity - many species of fishes, algal aquatic plants, crustaceans, etc. But due to mismanagement, only a few lakes in the world have all these features.
| POLLUTION IN LAKES: |
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When a lake is clean, it is beautiful to behold. But when it is dotted by filth, it becomes an eyesore. Instead of being beneficent, lakes have become monsters. The water is no longer safe to drink, thanks to the effluents, which are drained from the surrounding industries. The poisonous substances that are present in the effluents choke the fishes to death. It has disturbed the ecological balance, eliminating a good source of food. Dumping garbage into the lakes has become a common occurrence. Those who live in large industrial towns hardly get fresh and uncontaminated waterscapes.
Come Ganapathi festival, all pollution is let loose on Sankey Tank, Ulsoor Lake and Lalbagh Lake. These lakes were once the pride of the garden city of India. They are now dotted with flowers, colour papers and what not. The stench near these lakes is intolerable. Weeds occupy almost half of their areas, throttling them to extinction.
| LAKE CONSTANCE: |
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Lake Constance is one of the world's most famous tourist spots, located on the German Swiss border, where the demographic numbers are amazingly high. It is also an important industrial environment. Here, the production of sodium tripolyphosphate (used as an additive - substance added to foods for preservation) increased a hundred fold between 1947 and 1970 (and the level of the surface water increased in proportion due to waste accumulation). Lake Constance has no outflow, that is, it is an enclosed water body without outlets. Here, the phosphate level rose from a natural level of 0.2mg/m3 to 3mg/m3. This kind of high accumulation of phosphate has supported the growth of algae and the associated unsightly 'blooms'.
| CLEAR LAKE, CALIFORNIA: |
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This is about 100 sq. miles in area, 70 miles north of San Francisco and used for recreation. Following complaints about numerous gnats, the lake was first treated with DDT in 1949 and the nuisance was controlled; following recovery in the numbers of gnats, a successful re-application was made in 1954. However, by 1957, the gnats and numerous other insect species had developed resistance to DDT. Towards the end of 1954 many dead western grebes were found, leading to a public out cry which ultimately ended the treatment using DDT. These birds were fish-eating divers and their death was attributed to bioaccumulation through phytoplankton - zooplankton - consuming fish - carnivorous fish-grebes. DDT was dispersed in the lake at a concentration of only 20 ppm, but the birds had accumulated DDT in their fat up to 1600 ppm, a bioaccumulation factor of 80000.
| PREVENTION: |
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Systematic cleaning of lakes (once in 5 months) should be done in order to fight the dark cloud of pollution. Dredging or de-silting of the lakes should be done carefully in order to increase their depth to hold more water. This is also important to maintain the water quality and improve the breeding conditions of the fish. The de-silted soil can be dried and used for construction purposes. The waste materials if any, can be used as fuel. Weeds should be removed regularly (again at least once in 5 months). They can be used as fodder (unless they are harmful), as well as fuel. Organisations / monitoring bodies similar to Central Ganga Authority have to be created for curtailing water pollution. Though small industries cannot be ordered to close, they must be forced to lessen the amount of waste produced and treat the waste. Strict laws have to be enforced to stop people from bathing in lakes. They should be penalised if they dump or throw anything into the water bodies.
To control algal growth, alternative sequestering agents have to be substituted for phosphate. One of these is the chelating agent nitriloacetic acid, which associates with Ca and Mg. Nitroloacetic acid (NTA) is, however, environmentally suspect since it also sequesters and therefore mobilises heavy metals such as Pb and cadmium from sediments. The most promising alternative to phosphate is zeolite, which is polynuric sodium aluminium silicate. A simplified form is the structure 14, where the trivalent Al atoms sharing with the tetravalent Si acquire a surplus negative charge; as a result the zeolite associates with Ca ions in order to achieve electrical neutrality.
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It is mankind's duty to protect these beautiful assets of nature. Live and let live should be the principle. It is just a matter of time before the lakes are annihilated. Man has the right to use but not abuse. Man can't afford to fail in this venture, as it would result in the future generations suffering disastrous consequences. Mother Nature is being throttled - Save her. A concerted global effort is the need of the hour.
| ADDRESS |
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1.) Xth Std Poorna Prajna Education Centre,
Sadashivanagar,
Bangalore
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