Environmental degradation
The overall lowering of environmental qualities due to the damages caused by both natural events and human activities in the basic structure of the environment at local ,regional, and global levels adversely affecting all living organisms including man
Environmental pollution
An undesirable change in physical, chemical, and biological characteristics of air ,water and soil due to anthropogenic activities which may harmfully affect the life or create a potential health hazard to all living organisms in the biosphere
Pollutants
• Anything living or non living or any physical agent that in its excess makes any part of the environment undesirable for survival
• Detrimental effect on all living organisms
• Example: wastes of solid liquid gas as well as energy
Contaminants
• Are substances that do not occur naturally but are introduced by human activities into the environment.
• May or may not have detrimental effect
• Example Methyl isocyanate
•
Air pollution
The Air(Prevention and Control of Pollution )Act ,1981defines air pollution as The presence in the atmosphere of any air pollutant In other words, Air pollution is the introduction of chemicals, particulate matter, or biological materials that cause harm or discomfort to humans or other living organisms, or damages the natural environment ,into the atmosphere
According to The Air(Prevention and Control of Pollution )Act ,1981 air pollutant means any solid ,liquid or gaseous substance (including noise) present in the atmosphere in such concentration as may be or tend to be injuries to human beings or other living creatures or plants or property or environment
Pollutants can be in the form of solid particles, liquid droplets, or gases. In addition, they may be natural or man-made.
Pollutants can be classified as either primary or secondary. primary pollutants are substances directly emitted from a process, Example Sulfur oxides,nitrogen oxides ,carbon monoxide ,carbon dioxide,CFC,ammonia, Toxic metals such as lead ,cadmium ,copper
Secondary pollutants are not emitted directly. Rather, they form in the air when primary pollutants react or interact. examples of secondary pollutants are ground level ozone ,acid rain, PAN
Sources of air pollution
Natural sources
- Dust from natural sources, usually large areas of land with little or no vegetation.
- Methane, emitted by the digestion of food by animals, for example cattle
- Radon gas from radioactive decay within the Earth's crust. Radon is a colorless, odorless, naturally occurring, radioactive noble gas that is formed from the decay of radium. It is considered to be a health hazard. Radon gas from natural sources can accumulate in buildings, especially in confined areas such as the basement and it is the second most frequent cause of lung cancer, after cigarette smoking.
- Smoke and carbon monoxide from wildfires
- Volcanic activity, which produce sulfur, chlorine, and ash particulates
Man made
Cars, trucks, jet airplanes and other combustion engine vehicles cause air pollution. The exhaust from these contains carbon monoxide, nitrous oxide and gaseous oxide.
Factories, office buildings homes and power-generating stations burn fossil fuels, which cause air pollution. The burning of oil and coal (fossil fuels) also contributes to smog. This air pollution destroys plants, damages buildings and creates oxidation on iron.
Petroleum refineries release hydrocarbons and various particulates that pollute the air.
Some power lines are not insulated and are high voltage. This creates air pollution.
Radioactive fallout causes air pollution from the nuclear energy dispersed, which is a dust.
Dust from fertilizers used to help plants grow, causes air pollution.
. Mining causes air pollution by releasing a variety of particles.
Mills and plants, include paper mills, chemical plants, iron mills, steel mills, cement plants and asphalt plants, release emissions into the air causing air pollution.
Indoor Air Pollution
Many houses in the underdeveloped countries including India, use fuels like coal, dung-cakes, wood and kerosene in their kitchens. Complete combustion of fuel produces carbon dioxide which may be toxic however incomplete combustion produces the toxic gas carbon monoxide
Effects of air pollution
• Effects on human health
It can result in lung cancer, asthma, chronic bronchitis
• Effects on plants
Air pollutants affect plants by entering the cells through stomata. The damage results in the death of the plant.
• Effects on aquatic life
Air pollutants mixing up with rain can cause high acidity in fresh water lakes, which affects aquatic life especially, fish
• Effects on materials
Because of their corrosiveness, particulates can cause damage to exposed surfaces
Control of air pollution
Air pollution can be minimized by the following methods
• Setting up of industries after proper environmental impact assessment studies
• Using low sulphur coal in industries
• Removing nitrous oxides during the combustion process
• Using mass transport system ,bicycles etc
• Shifting to less polluting fuels
• Using non-conventional sources of energy
• Using biological filters
• Planting more trees
Noise pollution
The unpleasant and unwanted sound is called noise
Effects of noise pollution
• Interferes with man’s communication
In a noisy area, communication is severally affected.
• Hearing damage
Noise can cause temporary or permanent hearing loss .It depends on the intensity and duration of sound level
• Physiological and psychological changes
Continuous exposure to noise affects the functioning of various systems of the body. It may result in hypertension, insomania (sleeplessness), digestive disorders
Control of noise pollution
• Reduction in the sources of noise
• Proper oiling will reduce the noise from machinery
• Noise making machines should be kept in containers with sound absorbing media.
• Use of sound absorbing silencers. Silencers can reduce noise by absorbing sound
• Planting more trees that have broad leaves
• Through law ,legislation can ensure that sound production is minimized at various social functions
• Unnecessary blowing of horn should be restricted especially in vehicle-congested areas .
•
Water pollution
Water pollution can be defined as an alteration in physical, chemical or biological characteristics of water, making it unsuitable for the designated use in its natural state.
Sources
• Industries
• Power plants
• Underground coal mines
• Offshore oil wells
Ground water pollution: sources
Septic tanks, industry(textile ,chemical ,tannery)mining etc are mainly responsible
Surface water pollution : sources
Sewage, industrial effluents, synthetic detergents, agrochemicals, oil, waste heat
Effects
• Toxic compounds
• Oxygen –demanding wastes
• Nitrogen and phosphorous compounds
• Waterborne diseases
• Reduction in dissolved oxygen in water resources
Control of water pollution
It is easy to reduce water pollution from point sources by legislation. However due to absence of any defined strategies it becomes difficult to prevent water pollution from non-point sources. The following measures may be taken.
• Judicious use of agrochemicals like pesticides and fertilizers which will reduce their surface run-off and leaching Avoid the use of these on sloped lands.
• Use of nitrogen –fixing plants to supplement the use of fertilizers
• Adopting integrated pest management to reduce reliance on pesticides
• Separate drainage of sewage and rain water should be provided
• Plantation
• Industrial effluents to be allowed only after treatment
Thermal pollution
• The presence of excessive heat in the water which can cause undesirable changes in the natural environment
Sources
Heat producing industries like thermal power plants, nuclear power plants, refineries, steel mills
Effects
• The dissolved oxygen content of water is decreased as the solubility of oxygen in water is decreased at high temperature
• High temperature becomes a barrier for oxygen penetration into deep cold waters
• Toxicity of pesticides ,detergents and chemicals in the effluents increases with increase in temperature
• The composition of flora and fauna changes
• Fish migrations are affected due to the formation of various thermal zones
• Discharge of hot water near the shores can disturb spawning and can even kill young fishes.
Control
• Cooling ponds
Man made bodies of water
• Spray ponds
• Co-generation
A process where waste heat is recycled for domestic heating purposes
• Cooling towers:
It transfers waste heat to the atmosphere through evaporation.
Marine pollution
Sources
1. Rivers which bring pollutants from their drainage basins
2. catchment areas and coastlines where human settlements in the form of hotels ,industry, agricultural practices have been established
3. oil drilling and shipping
control of marine pollution
• Toxic pollutants from industries and sewage treatment plants should not be discharged in coastal waters
• Run –offs from non-point sources should be prevented from reaching coastal areas
• Dumping of toxic ,hazardous wastes and sewage sludge should be banned
• developmental activities on coastal areas should be minimised
• Oil and grease from service stations should be processed for reuse
• Oil from ballasts should not be dumped into sea
• Drilling should not be allowed in ecologically sensitive coastal areas
Soil pollution
Sources
Dumping of various types of materials especially domestic and industrial wastes causes soil pollution
Effects
Human health
Some of the persistent toxic chemicals accumulate in the food chain and ultimately affect human health. Sewage sludge has many types of bacteria, viruses, which may cause various types of diseases.
Soil fertility
Various types of chemicals like acids, alkalis pesticides and insecticides found in the industrial discharges affect soil fertility by causing changes in its physical chemical and biological properties
Control
• Proper treatment of effluents should be done before discharging them into the soil
• Solid wastes should be properly collected and disposed of by appropriate methods
• From the wastes useful products should be recovered
• Biodegradable organic waste should be used for the generation of biogas
• Microbial degradation of biodegradable substances is a scientific approaches foe reducing soil pollution
•
Industrial pollution
Although there are many types of pollution and sources, industry has contributed its share over the last couple hundred years. Industrial pollution can include air pollution like carbon dioxide, monoxide and ozone; water pollution in the form of petroleum spillage, radiation and heat; and other pollutants like heavy metals. These pollutants make their way into delicate ecosystems and damage wildlife and plant life, as well as public health.
Sustainable development
To meet the basic requirements of ever increasing population, industrialization is a must, but it results in pollution, environmental degradation, and causes ecological imbalances .At the same time industrial development cannot be avoided as it creates job opportunities, raises the standard of living and solves unemployment problems. In view of this, a balance has to be struck so that development and environmental protection can occur simultaneously
Sustainable development is the development that meets the needs of the present without jeopardizing the needs of future generations .In other words, every generation should leave air, water and soil resources as pure and unpolluted. Sustainable development means concerns for protecting environment and avoiding depletion of non-renewable resources.
It explains how economic, social and environmental systems interact at various scales of operation in a way that would lead to form an optimal balance among the three subsystems. Sustainable development has 3 interdependent components
Economic development- Utilisation of natural resources for cultivation, industrialisation creating job opportunities and raising quality of life
Social development-providing basic needs like food, clothes, health, education
Environmental protection-safe environment to the present as well as the future generations.
For achieving sustainable development
Control population growth
Reduction in excessive usage of resources and enhancing resources conversation
Recycling and reuse of materials for waste minimization
Equal distribution of resources
Support social justice and equality
Natural resources
A form of energy which is essential for the functioning of organisms, populations and ecosystems. Examples are water, air ,soil,minerals,forests,crops and wild life.
Odum’s classification
Recyclable Non-recyclable
Renewable resources
Resources that can be replenished through rapid natural cycles are called Renewable resource Examples plants, animals ,water ,soil, wood products natural rubber
Non- renewable resources
Resources that cannot be replenished through rapid natural processes are known as Non- renewable resources. Once a non-renewable resource is consumed it is gone forever .Then we have to find a substitute for it or do without it example fossil fuels, metals, minerals
Recyclable-These are non –renewable resources which can be collected after they are used and can be recycled. example ores of aluminium, copper ,mercury, phosphate stock ,potassium…
Non-recyclable-These are non- renewable resources which cannot be recycled in any way example fossil fuel, Uranium
Biotic resources
These are living resources that are able to reproduce or replace them example forests wild life
Abiotic resources
These are non –living resources that are not able to replace themselves example petrol minerals
Inexhaustible resources
Resources which are not changed by man’s activities and are abundantly available example solar energy, atomic energy, wind power .Most of the renewable resources are classified as inexhaustible But if not maintained properly they become extinct. For example Water is renewable only if water continues to percolate in the soil at a rate at which it is removed.
Exhaustible resources
Are limited in nature and non –maintainable Example coal petrol
Forest resources
Covering earth like a blanket, forests not only produce innumerable material goods, but also provide several environmental services which are essential for life.
Uses of forests
Commercial uses
Forests provide us a large number of commercial goods which include timber .firewood, food items, non-edible oils, robber, fibers, fodder, medicines and many more items
Many forest lands are used for mining, agriculture, grazing, and recreation and for development of dams
Ecological uses
Production of oxygen by photosynthesis
Reducing global warming-The main greenhouse gas carbon dioxide is absorbed by the forests as araw material for photosynthesis Thus it helps in reducing the amount of carbon dioxide and also global warming
Wild life habitat-Forests are the homes of millions of wild animals and plants
Soil conservation –Forests bind the soil particles tightly in their roots and prevent soil erosion
Pollution moderators-forests can absorb many toxic gases and can help in keeping the air pure and clean. They can absorb noise and help in preventing noise pollution
Major causes of Deforestation
Shifting cultivation
• Fuel requirements
• Raw materials for industrial use
• Developmental projects like dams ,roads
• Growing food needs-To meet the demands of a rapidly growing population agricultural and settlements are created permanently by clearing forests
• Overgrazing-cleared lands are turned into grazing lands. Overgrazing by cattle leads to further degradation of these lands
Major consequences of deforestation
• Existence of many wild life species is in danger due to destruction of their natural habitat
• Biodiversity is lost
• Hydrological cycle gets affected, thereby influencing rainfall
• Soil erosion and loss of soil fertility
• The effects global warming may aggravate due to loss of oxygen generation and increase in the level of carbon dioxide in the air
No comments:
Post a Comment