Let’s a talk on pollution. Pollution can, therefore, be defined as any undesirable change in the physical, chemical or biological characteristics of any component of the environment (air water soil) which can cause harmful effect on various forms of life or property.
It could be various type: Air, Noise, Water, Thermal, and Soil Pollutions.
■ POLLUTION CASE STUDIES
Air Pollution Episodes: A series of air pollution disasters have occurred in the past 75 years from Meuse Valley, Belgium (1930) to the Chernobyl nuclear disaster in, the erstwhile USSR (1986). Some of the important ones are given below:
Donora air pollution disaster:
Donora of Pennsylvania (in the USA) is a small mill town dominated by the steel mill, zinc smelter, and sulphuric acid plant.
- A four days fog occurred from October 25-31, 1948. Due to anticyclonic weather conditions, there was no air movement and temperature inversion had set in due to sea breeze conditions.
- Donora lies in a horseshoe-shaped valley on the Monongahela River, south of Pittsburgh with steep raising hills on each side of the river.
- The fog which formed due to the accumulation of cold air at the bottom of the river valley persisted for 4 consecutive days. This condition, when a cold layer is trapped below the warm layer, is called an inversion.
- The top fog layer reflected the solar radiations during the daytime. So the heat received by it was not sufficient to break the inversion. During night times the top layer had been losing heat which further cooled the layer to stabilize. Wind speed in the inversion layer was also slow.
- The deadly pollutants emitted by the steel mill, zinc smelter, and sulphuric acid plant got trapped and concentrated in the stable weather conditions of the valley and remained there for four days.
- About 6000 of the town’s 14,000 inhabitants fell ill and 20 of them died.
The Bhopal Gas Tragedy:
The world’s worst industrial accident occurred in Bhopal, M.P., India on the night of 2nd and morning of 3rd December 1984.
- It happened at Union Carbide Company which used to manufacture Carbaryl (Carbamate) pesticide using Methyl isocyanate (MIC). Due to an accidental entry of water in the tank, the reaction mixture got overheated and exploded because its cooling system had failed. Other safety devices also did not work or were not in the working condition.
- Forty tons of MIC leaked into the atmosphere which might have contained 40 kg of phosgene as an impurity.
- MIC gas at lower concentrations affects lungs and eyes and causes irritation in the skin.
- Higher amounts remove oxygen from the lungs and can cause death.
- In the winter night of December, there were fog-like clouds over south and east of the plant.
- The gas spread over 40 Km2 area About 5100 persons were killed (2600 due to direct exposure to MIC and other 2500 due to aftereffects of exposure) according to Indian officials.
- About 2,50,000 persons got exposed to MIC.
- An estimated 65,000 people suffered from the severe eye, respiratory, neuromuscular, gastrointestinal and gynecological disorders. About 1000 persons became blind.
- Without counting the damage of human lives, it cost about S 570 million in clean up and damage settlement. This tragedy could have been averted had the company spend about $ 1 million on safety improvement.
The Love Canal Tragedy
The Love canal tragedy occurred in a suburb of Niagara Falls, New York. The love canal was built by William Love which was later dug up and was used to dump sealed steel drums of chemical wastes by Hooker Chemicals and Plastics Corporation between 1942-1953.
- In 1953, the dump site was covered with clay and top-soil by the company and was sold to the city Board of Education which built an elementary school on that site. Houses were also built near the school. In 1976, the residents started complaining of the foul smell. Children playing in the canal area received chemical burns.
- In 1977, the corroded steel containers started leaking the chemicals into storm sewers, the basement of homes and the school playground.
- About 26 toxic organic compounds were identified. The dump site was covered with clay and the leaking wastes were pumped to a new treatment plant.
- The affected families were relocated.
There could be many more dump sites similar to Love canal, especially in the third world countries. Who knows what amount of harm such dump sites are causing to the underground aquifers?
Chernobyl Nuclear Disaster :
Chernobyl nuclear accident is the worst nuclear disaster in the history of human civilization which occurred at Chernobyl, Ukraine in the erstwhile USSR (Now CIS). On 26 April 1986, the accident occurred at the reactor of the Chernobyl power plant designed to produce 1000 MW electrical energy. The reactor had been working continuously for 2 years. It was shut down on april 25, 1986 for intermediate repairs. This period coincided with the period when people including the top executive were busy in the preparation for the national holiday, the May Day, Due to faulty operations of shutting down the plant, an explosion occurred in the reactor at 01.23 firs on April 26, 1986. Three seconds later another explosion occurred.
- The explosion was so severe that the 1000 tonne steel concrete lid of the reactor 4 blew off. The fire started at the reactor due to combustion of graphite rods.
- The reactor temperature soared to more than 2000°C. Fuel and radioactive debris spewed out in a volcanic cloud of molten mass of the core and gases.
- The debris and gases drifted over most of the northern hemisphere. Poland, Denmark, Sweden and Norway were affected.
- On first day of the accident 31 persons died and 239 people were hospitalized.
- Since the plume was rich in iodine-131, Cesium-] 34 and Cesium-137, it was feared that some of the 5,76,000 peo-ple exposed to the radiations would suffer from cancer specially thyroid cancer and leukemia.
- Children were more susceptible as Iodine- I 31 is ingested mainly through milk and milk products.
- Since children consume more milk and their thyroid glands are in the growing stage, an increase in thyroid cancer in children from areas near Chernobyl was registered.
- More than 2000 people died. People suffered from ulcerating skin, loss of hair, nausea, and anemia.
- Agricultural produce was damaged for years. Intense radiations destroyed several fields, trees, shrubs, plants etc. Flora and fauna were destroyed.
- Blood abnormalities, hemorrhagic diseases, changes in lungs, eye diseases, cataract, reproductive failure and cancer cases increased. Sweden and Denmark banned the import of contaminated Russian products.
The nuclear energy is a cheap, inexhaustible and non-polluting source of energy. However, in the absence of proper care and caution, disasters like Chernobyl can rock the society.
Pollution Problem Areas List of India as Identified by CPCB (Central Pollution Control Board | Government of India )
|S. No.||Name of city||State of india|
|14.||Najafgarh Drain Basin||Delhi|