Pollution is any undesirable change in physical, chemical or biological characteristics of air, land, water or soil. Agents that bring about such an undesirable change are called as pollutants.
In order to control environmental pollution, the Government of India has passed the Environment (Protection) Act, 1986 to protect and improve the quality of our environment (air, water and soil).
Air pollution is any undesirable change in the physical, chemical or biological characteristics of air.
Harmful effects of air pollution
Cause of air pollution
Control of air pollution
Any undesirable change in the physical, chemical or biological characteristics of water is called water pollution.
Sewage is a domestic waste contains biodegradable organic matter, nitrates, phosphates, and other nutrients, and toxic metal ions.
The amount of organic matter in sewage water by measuring Biochemical Oxygen Demand (BOD). Biochemical oxygen demand is the amount of oxygen required by aerobic microorganisms to break down all organic matter.
Micro-organisms involved in biodegradation of organic matter in the receiving water body consume a lot of oxygen, and as a result there is a sharp decline in dissolved oxygen downstream from the point of sewage discharge which causes mortality of fish and other aquatic creatures.
Sewage from our homes as well from hospitals contains many undesirable pathogenic microorganisms which can cause diseases like dysentery, typhoid, jaundice, cholera.
Presence of large amounts of nutrients in waters also causes excessive growth of planktonic (free-floating) algae, called an algal bloom.
Algal blooms cause deterioration of the water quality and fish mortality and some bloom-forming algae are toxic to human beings and animals.
Water hyacinth (Eichhorniacrassipes) called as ‘terror of Bengal’ is the most problematic water weed which grow abundantly in eutrophic water bodies, and lead to an imbalance in the water ecosystem.
Water pollution, to a larger extent, can be controlled by a variety of methods.
Rather than releasing sewage waste into water bodies, it is better to treat them before discharge.
Practising this can reduce the initial toxicity and the remaining substances can be degraded and rendered harmless by the water body itself.
If the secondary treatment of water has been carried out, then this can be reused in sanitary systems and agricultural fields.
Solid waste generally referees to the any garbage, refuse, sludge from a wastewater treatment plant, water supply treatment plant, or air pollution control facility and other discarded materials including solid, liquid, semi-solid, or contained gaseous material, resulting from industrial, commercial, mining and agricultural operations etc.
Bio-degradable: The wastes which can be degraded by microorganisms. Example- food materials.
Non-biodegradable: The wastes which cannot be degraded or takes long time to get degraded. Example – plastic.
An agrochemical or agrichemical, a contraction of agricultural chemical, is a chemical product used in agriculture. In most cases, agrichemical refers to pesticides including insecticides, herbicides, fungicides and nematicides.
Increasing amounts of artificial fertilizers can cause eutrophication.
Integrated organic farming is a cyclical zero-waste procedure where waste products from one process are cycled in as nutrients for other processes.
Organic farming is a technique, which involves the cultivation of plants and rearing of animals in natural ways.
This process involves the use of biological materials, avoiding synthetic substances to maintain soil fertility and ecological balance thereby minimizing pollution and wastage.
Area under organic farming was 42,000 hectares during 2004-05 which had increased to 1.08 hectares by March 2010.
Radioactive waste is defined as material that contains, or is contaminated with, radionuclides at concentrations or activities greater than clearance levels as established by individual countries' regulatory authorities, and for which no use is currently foreseen.
There are three types of nuclear waste, classified according to their radioactivity: low-, intermediate-, and high-level. The vast majority of the waste (90% of total volume) is composed of only lightly-contaminated items, such as tools and work clothing, and contains only 1% of the total radioactivity.
The greenhouse effect is a natural process that warms the Earth's surface. When the Sun's energy reaches the Earth's atmosphere, some of it is reflected back to space and the rest is absorbed and re-radiated by greenhouse gases.
Global warming is the long-term heating of Earth's climate system observed since the pre-industrial period due to human activities, primarily fossil fuel burning, which increases heat-trapping greenhouse gas levels in Earth's atmosphere.
Ozone is a layer in the earth’s stratosphere which acts as a shield absorbing ultraviolet radiation from the sun. The decreases have occurred in the stratospheric ozone layer where most ozone resides.
In the early 1990s, the depletion of global total ozone reached a maximum of about 5% below the 1964–1980 aver- age. The depletion has lessened since then and now averages about 3.5% for 2006–2009.
UV rays are highly injurious toliving organisms as the chemical bonds within DNA and proteins of living organisms break by its high energy.
The thickness of the ozone in a column of air from the ground to the top of the atmosphere is measured in terms of Dobson units (DU).
Ozone gas is continuously formed by the action of UV rays on molecular oxygen, and also degraded into molecular oxygen in the stratosphere so there should be a balance between production and degradation of ozone in the stratosphere.
The balance has been disrupted due to enhancement of ozone degradation by chlorofluorocarbons (CFCs).
The degradation of natural resources can occur, not just by the action of pollutants but also by improper resource utilisation practices.
Deforestation is the permanent removal of trees to make room for something besides forest. This can include clearing the land for agriculture or grazing, or using the timber for fuel, construction or manufacturing.
Forest fires: Each year, fires burn millions of hectares of forest worldwide. Fires are a part of nature but degraded forests are particularly vulnerable.
Fuelwood harvesting: Over-harvesting for domestic use or for commercial trade in charcoal significantly damages forests.
Mining: The impact of mining on tropical forests is growing due to rising demand and high mineral prices.
Climate change: Forest loss is both a cause and an effect of our changing climate. Climate change can damage forests, for instance by drying out tropical rainforests and increasing fire damage in boreal forests.
Illegal and unsustainable logging: Illegal logging occurs in all types of forests across all destroying nature and wildlife, taking away community livelihoods and distorting trade.
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