How do one activities affect the environment ?
There are two major environmental problems :
(1) Solid waste and their disposal
(2) Depletion of ozone layer.
(1) Solid waste and their disposal : Solid waste generally comes from residences, cattle sheds, industries, agricultural fields, any many other places. It includes peelings of fruits and vegetables, other kitchen waste, ash, paper, cow dung, human excreta, glass, pastics, leather and rubber articles, brick, sand, worn out clothes and metal objects etc. When accumulated, these heaps of solid waste make the surroundings dirty, and pollute the soil.
The sight of a dustbin overflowing and the unpleasant smell rising from it are the familiar sights and smells of a crowded city. You look away from it and hold your nose as you cross it. Have you ever thought that you also have a role to play in the creation of this unpleasant odour ? Whether we can also play any role in reducing this smell and making this waste bin look a little more attractive if we follow proper methods of disposal of the waste generated in our houses ? What happens to the materials thrown away ?
|S. No.||.Biodegradable Waste||Non-biodegradable Waste|
|1||They can be broken down into simpler substances by the activity of biological catalayst s called enzymes (present in surrounding bacteria or other saprophytes). Physical processes like heat and temperature help in the functioning of enzymes.||They can't be broken down into simpler and harmless products because the biological catalysts called enzymes can't act upon them. They can be acted upon only by some physical processes like heat and pressure|
|2||They can enter the biogeochemical cycles||They cannot enter the biogeochemical cycles|
They become pollutants only when they accumulate in large quantities and not degraded at the right time..
|They always act as pollutants whether present in small or large quantity|
|4||All the biodegradable wastes should be treated properly before discharging them into wateror soil.||They can't be treated properly before discharging them into water or soil.Instead,they can be either recycled or reused.|
|5||They do not persist in the environment for a long time.||They persist in the environment for a long time.|
|6||Examples: Urine and faecal matter, Sewage, Paper, Vegetable and fruit peels, Agricultural residues, Wood and Cloth.||Examples: Heavy metals like Mercury, Lead ,Arsenic, Radioactive wastes like Uranium, Plutonium, Insecticides and Pesticides like DDT and BHC|
Type of solid wastes :- 2 Types
— Biodegradable Wastes : They are those waste materials which can be broken down into simpler, non-poisonous substances by the action of micro-organisms, for example, Cattle dung, Waste vegetables, fruits, and Compost etc.
— Non-biodegradable Wastes : The waste materials which cannot be broken down into simpler substances easily in nature, for example, Aluminium Cans, Coal, DDT, Plastics and Radioactive wastes.
Modes of Waste Disposal
Some prominent methods of waste disposal are :
1. Land fills : In urban areas, majority of the solid wastes are buried in low lying areas to level the uneven surface of land. This method of waste disposal is commonly called land fills.
2. Recycling of wastes : Number of solid wastes (paper, plastics, metal, etc.) can be recycled by sending them to respective recycling units. For instance, paper is sent for recycling into special paper mills ; brock plastic (e.g., plastic bags, buckets, bowls, dishes, mugs, disks, etc.) are sent to plastic processing factories.
3. Preparation of compost : Household waste such as peeling of fruits and vegetables, left-over food, fallen dead leaves of kitchen garden plants and potted plants etc. can be converted into compost and used as manure.
4. Incineration or burning at high temperature : Incineration is the process of burning of substance at high temperature (usually more than 1000°C) and ultimately converting them into ashes. This ash can be diposed of by land fills. In cities, municipal committees / corporations generally do large scale disposal of waste by incineration.
5. Production of biogas and manure : Biodegradable, waste can also be used in biogas plants to generated biogas and manure. Biogas is a cheap source of fuel, and manure, a cheap fertilizer.
Depletion of Ozone layer
Ozone is poisonous in nature.
Ozone is formed in atmosphere by the action of ultraviolet radiation on oxygen gas.
The high energy ultraviolet radiation (UV radiation) coming from the sun splits oxygen gas into free oxygen atoms
O2 2O (oxygen atom)
The free oxygen atoms are highly reactive. One oxygen atom reacts with an oxygen molecule to form an ozone molecule.
O2 + O → O3 (Ozone molecule)
It is a layer of the earth's atmosphere, where ozone is concentrated. The Ozone layer is very important for the existence of life on earth because it absorbs most of the harmful ultraviolet radiation coming from the sun and prevents them from reaching the earth.
The thining of ozone layer is commonly called ozone depletion. Ozone is being depleted by air pollutants. Chlorofluorocarbons (CFCs) are air pollutants that are mainly responsible for the depletion of ozone layer in the stratosphere. Besides, methane (CH4) and oxides of nitrogen (NOx) also cause destruction of ozone.
Effect of Ozone Depletion
(i) Ultra violet radiations cause skin cancer.
(ii) These cause damage to eyes and also can cause increased incidence of cataract disease in eyes.
(iii) These cause damage to immune system by lowering the body's resistance to diseases.