In this article, You will read Environmental Hazards and Remedial Measures – for UPSC IAS.
- Environmental Hazards and remedial measures
Environmental Hazards and remedial measures
An environmental hazard is a substance, a state, or an event that has the potential to threaten the surrounding natural environment/or adversely affect people’s health, including pollution and natural disasters such as storms and earthquakes.
Environmental hazards may be defined as those extreme events either natural or anthropogenic which exceed the tolerable magnitude within or beyond certain time limits, make adjustment difficult, resulting in catastrophic losses of property, income, and lives.
The term environmental hazard may be distinguished from environmental disaster as follows. Hazards are the processes that cause an accident or extreme event or danger whereas disaster is a sudden adverse or unfortunate extreme event that causes great damage to human beings as well as plants and animals, i.e., disasters occur rapidly, instantaneously, and indiscriminately. Thus, environmental hazards are the processes whereas environmental disasters are the results or responses of environmental hazards.
Environmental hazards directly affect people, businesses, and wildlife. The dependence of society on agricultural production, energy supply, chemical use, and transport and communication infrastructures, highlights the need for increased resilience to environmental hazards as a high priority.
Hazards include floods, droughts, emerging diseases, and invasive species, and pollution of soil, water, and air. Scientific data are crucial for characterizing natural and anthropogenic hazards. This forms the objective evidence-based needed to assess the threats posed and how they can be mitigated. The severity of impacts from environmental hazards depends on the hazards themselves and also on exposure and vulnerability.
Quantifying the current and likely future risks from environmental hazards is an urgent and significant need. A greater challenge is understanding how hazards interact with one another and other key environmental components, such as land-use, climate change, and the growing human population.
By assessing the risk of natural environmental hazards, and those caused by humankind, we will be better able to predict and develop strategies to address the threats they pose to society, the economy and our environment.
On the basis of main causative factors, the environmental hazards and disaster are of two types:
- Natural hazards and disaster and
- Anthropogenic hazards and disaster.
Natural hazards are further subdivided into two categories:
- Planetary hazards and
- Extra planetary hazards and disasters.
Planetary hazards and disasters are of two types:
- Terrestrial or endogenous hazards, (volcanic eruption, Earthquake) and
- Atmospheric or exogenous hazard (Cyclone, Flood, drought)
Anthropogenic hazards and disasters are of three types:
- Physical hazards (landslides, soil erosion, Earthquakes)
- Chemical hazards and disasters (sudden outbreak of lethal poisonous gases from industries, nuclear explosion, leakage of radioactive elements,
- Biological hazards and disaster (sudden rise in population of species in a given habited).
Earthquake and its management
An earthquake is a sudden movement of the ground surface, ranging from a faint tremor to a wild motion capable of shaking buildings apart and causing gaping fissures to open in the ground. It is caused by an abrupt release of slowly accumulating stress.
In other words, earthquake is a form of energy of wave motion transmitted through the surface layer of the earth in widening circles from a point of sudden release the focus. The intensity of energy released by an earthquake is measured by the Richter scale, after the name of the scientist C.F. Richter (1935). Although the scale ranges between 0 and 9, it has no upper limit of number because it is a logarithmic scale. Another scale of the measurement of intensity of earthquakes is mercalli scale.
The intensity of an earthquake depends on a variety of factors e.g. magnitude, distance from the epicenter, acceleration, duration, amplitude of the wave, type of surface, water table, nature of the geometrical of the concerned region, and nature and type of constructions. A comparison between Mercalli intensity and Richter magnitude scale and corresponding effects is shown in the table.
Earthquakes are caused due to disequilibrium in any part of the crust of the earth. The disequilibrium is due to the volcanic eruption, faulting, and folding, up warping and down warping, the hydrostatic pressure of manmade water bodies like reservoirs and lakes, and plate movement Recently, Plate tectonic theory has been suggested to explain the occurrence of the earthquake.
According to this theory, the earth is composed of solid and moving plates having either continental, crust or oceanic crust, or both, the earth‘s crust is consisted of six major plates (Eurasian plate, Indian plate, American plate, African plate. Pacific plate, and Ataractic and twenty minor plates Antarctic plate) and twenty minor plates. These plates are moving in relation to each other due to thermal convective currents originating deep within the earth. Thus, all the tectonic events take place along the margins of the plate.
Earthquakes cannot be prevented from occurring but their impacts can be minimised by taking effective steps to reduce their severity, frequency and possible size. Some effective earthquake management steps are as follows:
- Earthquake-resistant buildings should be constructed in earthquake-prone zones. This is done either by keeping weak spots in the house to absorb vibration or by keeping pads or floats beneath the buildings.
- The earthquake zones should be avoided for settlement and construction of developmental structures.
- Wooden houses should be preferred in earthquake-prone seismic areas.
- Reinforce concrete columns should support the long walls.
- There should be reinforced concrete footing for each structure.
- The earthquake prediction should be made long before its occurrence in order to save lives and properties.
Flood and its management:
The overflowing of a river over its banks and submerging the surrounding areas is known as a flood. Flood is caused not only due to high precipitation but also due to increased deforestation, poor management of agricultural field, poor drainage system, unplanned urbanization, etc.
Flood results in a number of detrimental effects like damaging of houses, buildings, industries etc., damaging of standing crops, lowering of soil fertility, outbreak of epidemics, etc. Every year thousands of living organisms and the huge quantity of properties are lost due to floods in different rivers. Therefore, some preventive measures should be undertaken in order to reduce the severity of floods.
India being a country of many rivers and with a tropical climate is one of the most flood-prone countries of the world. Floods are frequent because most of the rivers are full of water during monsoons. Flooding is caused by the inadequate capacity within the banks of the rivers to contain the high flow of water due to heavy rainfall. Areas having poor drainage get flooded by the accumulation of water.
Almost all Indian states have been affected by serious floods. Apart from loss of lives of humans and cattle, on an average, every year 75 lakh hectares of land area is affected by the floods annually, accompanied by damage to the crops, houses and public utilities. Interestingly, while on one hand floods cause large scale losses on the other hand it helps agriculture by improving the soil quality.
Some important abatement steps may be outlined as follows:
- Dams and barrages should be constructed on river beds.
- Steps should be taken for the restoration of wet lands and implementation of water shed management programmes.
- Flood walls embankment and dikes should be constructed as physical barrier.
- The rivers should be interconnected.
- There should be massive afforestation over denude areas.
- There should be proper warning regarding the anticipated flood through different mass media.
- The Govt. should take emergency flood control measures with active participation of NGOs and local community.
- Flood water in low lying areas should be diverted through artificially constructed channels bordered by dikes.
Cyclone and its management:
A cyclone is a powerful circular or oval shaped swinkling storm with diameter of about 650 km, capable of causing large scale destruction. The tropical cyclones become highly disastrous because of their high wind speed of 180 to 400 km per hour, high tidal surges, high rainfall intensity, very low atmospheric pressures causing unusual rise in sea level, and their persistence for a longer period of time. The cumulative effects of high velocities of wind, torrential rainfall and transgression of sea water on coastal land create havoc in the affected areas, causing tremendous loss of lives and proper-ties.
The cyclones are called differently in different parts world as Hurricanes in North Atlantic Ocean, Typhoons in the North Pacific Ocean and Willy in sea around. Australia. A super cyclone hit the coastal belt of Orissa on 29th October 1999 which claimed more than 10,000 deaths and loss of more than 2000 crores of rupees.
According to Environmental Scientists, tropical cyclones are the consequences of globed climatic changes and the frequency of cyclones will go on increasing.
India has a long coastline, which is vulnerable to the tropical cyclones in the Bay of Bengal and the Arabian Sea. The Bay of Bengal region is frequently battered by storms and cyclones. Cyclones are intense lowpressure areas in the form of depressions or cyclone storms. Severe cyclones are associated with hurricane, winds etc.
There are two cyclone seasons in India, the pre-monsoon season (April-May) and the post-monsoon season (October-December). The states of Orissa, Andhra Pradesh, Tamil Nadu and West Bengal are the most affected states due to cyclones.
So in order to minimise the loss of life and property due to cyclones, the following preventive measures should be undertaken by the present society:
- There should be massive plantation on the coastal belt.
- There should be proper warning regarding the anticipated cyclone through different mass media.
- There should be temporary evacuation of population from affected or to be affected areas to safer places.
- Efforts should be made to preserve, maintain and replace coastal sand dune.
- Efforts should be made to maintain and preserve barrier islands and coastal islands.
- Cyclone proof structures and shelters should be constructed in the areas vulnerable to cyclone hit.
- The dams, embankments, wind breakers etc. should be constructed in order to prevent the locality from severity of cyclone.
- Government should take immediate steps to provide relief and rehabilitation measures to the cyclone affected peoples.
The rapid sliding of large mass of rocks, soil and mud along the slope of hill, mountain and highlands is termed as landslides. The landslides may occur due to heavy rainfall on the mountain slopes having loose soil and debris, due to excavation or due to deposition of loose ash after volcanic eruption. Sometimes, landslides may occur due to earthquakes and sudden rock failures.
Landslides can result from water saturation, slope modifications, and earthquakes. Techniques for reducing landslide and mudslide risks to structures include selecting flat land or stable slopes;
constructing channels, drainage systems, retention structures, and walls; planting groundcover; and soil reinforcement using geo-synthetic materials, and avoiding cut and fill building sites. Redirecting water that might affect steep slopes would greatly decrease landslides. Water loosens soil that might be necessary for sustaining land. Some areas that are at a high risk of landslides are:
- Areas where wildfires or human modification of the land have destroyed vegetation;
- Areas where landslides have occurred before;
- Steep slopes and areas at the bottom of slopes or canyons;
- Slopes that have been altered for construction of buildings and roads;
- Channels along a stream or river; and
- Areas where surface runoff is directed.
It would help to build structures away from these areas. There are also some precautions that can be taken before intense storms and rainfalls such as:
- Assume that steep slopes and areas burned by wildfires are vulnerable to landslides and debris flows.
- Learn whether landslides or debris flows have occurred previously in your area by contacting local authorities, a county geologist or the county planning department, state geological surveys or departments of natural resources, or university departments of geology.
- Contact local authorities about emergency and evacuation plans.
- Develop emergency and evacuation plans for your family and business.
- Develop an emergency communication plan in case family members are separated.
- These are all precautions that can be taken to prevent or stay away from landslides.
Drought and its management
The literary meaning of drought is an extended period of dry weather which is especially injurious to crops. However, different disciplines have different perceptions about drought. Meteorologists define it as rainless or rain-deficit period.
Agronomists consider drought as a condition of shortage of moisture for crop production. Economists view it as shortage of rainfall, which adversely affects agricultural production. A farmer considers drought as shortage of rainfall for critical operations and stages of crop growth.
Drought, if not managed properly and continued for more than two to three consecutive years, might lead to famine like situation. Drought adversely affects the economic and social life of the people. It aggravates poverty, water scarcity, and famine, the internal displacement of people, migration and social breakdown. Further, reduction in crop production increases the prices of those commodities and also affects the relative prices.
At the household level, a large drop in production translates into huge reduction in farm employment and income. The drop in income, coupled with rapidly increasing food prices result in severe and widespread decline in purchasing power. This also leads to migration and people become environmental refugees. Moreover, low income and less food production leads to malnutrition among the children. This has enormous social costs and causes a huge drain of economic resources.
According to Prof. Amartya Sen, malnutrition and famine could occur on a massive scale despite considerable food availability. It is shortage in food grain production which leads to a prolonged fall in food grain intake that starvation on a massive scale leads to excessive rise in death rates.
Drought Control Measures:
It is not very easy to forecast drought. Nowadays, computer-based studies help to get some ideas about it.
Some of the measures to mitigate drought are:
- Efficient use of rainwater and rain harvesting
- Introduction of dry farming techniques
- The lining of canals to prevent water loss
- Avoidance of overcropping
- Limiting settlements in drought-prone areas
- Introduction of horticulture plantation and
- Checking of desert migration.
Environmental pollution is one of the main threats for our planet. Environmental Pollution is any discharge of material or energy into water, land, or air that causes or may cause acute (short-term) or chronic (long-term) detriment to the earth’s ecological balance or that lowers the quality of life. In simple words, Environmental Pollution is a process of contaminating the environment in a way that it becomes unsafe to use. Environmental pollution is the effect of undesirable changes in our surroundings that have harmful effects on plants, animals and human beings. A substance, which causes pollution, is known as pollutant. Pollutants can be solid, liquid or gaseous substances present in greater concentration than in natural abundance and are produced due to human activities or due to natural happenings. Pollutants may cause primary damage, with direct identifiable impact on the environment, or secondary damage in the form of minor perturbations in the delicate balance of the biological food web that are detectable only over long time periods. The industrialization of our society, the introduction of motorized vehicles, rapid urbanization, the explosion of the human population, harnessing of the natural resources as well as unplanned sewage and waste disposal from industries and cities has been causing a tremendous increase in waste byproducts. Thus, environmental pollution usually occurs as a result of energy conversions and the use of resources which leaves their by-products behind in water, soil or air.
The natural resources which are freely available as a gift of nature are highly polluted. Depending upon the area or the part of environment affected, pollution may be broadly divided into following types:
1. Air pollution
2. Water pollution
3. Land pollution
4. Noise pollution
5. Radiation Pollution
6. Thermal pollution
Air pollution is one of the biggest challenges of present humanity. Air pollution means the presence of any abnormal material or property in the air that reduce the usefulness of the air resources. The term pollution may be referred in context with outdoor open atmospheric conditions, localized air condition, and enclosed space conditions. Air pollution occurs due to the presence of undesirable solid, liquid or gaseous particles in the air in quantities that are harmful to human health and the environment. Air may get polluted by natural causes such as volcanoes, which release ash, dust, sulphur and other gases, or by human activities. However, unlike pollutants from human activity, naturally occurring pollutants tend to remain in the atmosphere for a short time and do not lead to permanent atmospheric change.
Sources of Air Pollution
Among the major sources of pollution are power and heat generation, the burning of solid wastes, industrial processes, and, especially, transportation. The common pollutant gases emitted during the domestic burning of coal, kerosene oil, firewood, cow dung cakes, smoke from cigarettes etc. are carbon monoxide (CO), carbon dioxide (CO2), sulphur dioxide (SO2), etc. About 90% of global air pollution is constituted by the following pollutants.
- Carbon dioxide: It is one of the major gases which contribute towards air pollution. It is mainly produced during the combustion of fuel in factories, power stations, household, etc.
- Carbon monoxide: It is produced as a result of incomplete combustion of fossil fuels like coal, petroleum, and wood charcoal. Automobiles using diesel and petroleum are the major sources of carbon monoxide.
- Sulphur dioxide: It accounts for about 18% of all air pollution. It is produced by chemical industries, metals meltings, pulp and paper mills, oil refineries, etc.
- Oxides of nitrogen: A few oxides of nitrogen (NOx) are produced by natural processes as well as from thermal power stations, factories, automobiles, and aircraft. They account for about 6% of air pollution.
- Hydrocarbons: Hydrocarbons are a group of compounds consisting of carbon and hydrogen atoms. They either evaporate from fuel supplies or are remnants of fuel that did not burn completely.
- Particulate matter: Particulates are small pieces of solid material (for example, smoke particles from fires, bits of asbestos, dust particles, and ash from industries) dispersed into the atmosphere.
Effects of Air Pollution
(i) Effects on Human Health: Exposure to air pollution is associated with numerous effects on human health, including pulmonary, cardiac, vascular, and neurological impairments. The health effects vary greatly from person to person. High-risk groups such as the elderly, infants, pregnant women, and sufferers from chronic heart and lung diseases are more susceptible to air pollution. Children are at greater risk because they are generally more active outdoors and their lungs are still developing. Exposure to air pollution can cause both acute (short-term) and chronic (long-term) health effects.
(ii) Effects on plants: When some gaseous pollutants enter leaf pores they damage the leaves of crop plants. Chronic exposure of the leaves to air pollutants can break down the waxy coating that helps prevent excessive water loss and leads to damage from diseases, pests, drought and frost. Such exposure interferes with photosynthesis and plant growth, reduces nutrient uptake and causes leaves to turn yellow, brown or drop off altogether.
(iii) Effects of air pollution on materials: Every year air pollutants damage materials worth billions of rupees. Air pollutants break down exterior paint on cars and houses. All around the world air pollutants have discoloured irreplaceable monuments, historic buildings, marble statues, etc.
(iv) Effect on climate: Atmospheric changes induced by pollution contribute to global warming, a phenomenon which is caused due to the increase in concentration of certain gases like carbon dioxide, nitrogen oxides, methane and CFCs. There could be several adverse effects of global warming. With a warmer earth the polar ice caps will melt causing a rise in ocean levels and flooding of coastal areas. In countries like Bangladesh or the Maldives this would be catastrophic. If the sea level rises by 3m., Maldives will disappear completely beneath the waves.
Control measures for air pollution
Air pollution can be controlled by two fundamental approaches: preventive techniques and effluent control. One of the effective means of controlling air pollution is to have proper equipment in place. This includes devices for removal of pollutants from the flue gases though scrubbers, closed collection recovery systems through which it is possible to collect the pollutants before they escape, use of dry and wet collectors, filters, electrostatic precipitators, etc. Providing a greater height to the stacks can help in facilitating the discharge of pollutants as far away from the ground as possible. Industries should be located in places so as to minimize the effects of pollution after considering the topography and the wind directions. Substitution of raw material that causes more pollution with those that cause less pollution can be done.
Water is one of the most important biological components that sustain life. However, nowadays water is highly polluted and is one of the pivotal issues in the world. The water is said to be polluted when it has more “negative‖ qualities than “positive‖ ones. Water quality refers to the physical, chemical, and biological characteristics of water. Thus, in simple words, we can that polluted water is that water that has been abused, defiled in some way, so that it is no longer fit for use. Water pollution can be defined as “the presence of too much of undesirable substances in the water which tend to degrade the quality of water‘s physical, chemical and biological characteristics, making it unsuitable for beneficial use”.
Sources of Water Pollution
Water pollution is one of the most serious environmental problems. Water pollution is caused by a variety of human activities such as,
- Domestic sewage discharged into rivers from areas located on its banks.
- Excretory wastes of humans and animals in water bodies.
- Disposal of urban and industrial waste matter into water bodies.
- Industrial wastes effluents from urban areas containing high concentration of oil, heavy metals and detergents.
- Minerals, organic wastes, and crop dusting from agricultural fields with phosphate and nitrogen fertilizers that reach lakes, rivers, and sea (water becomes deoxygenated and poisonous, thus, cannot support aquatic life).
- Chemical fertilizers, pesticides, insecticides, herbicides and plant remains.
- Industrial waste water containing several chemical pollutants, such as calcium, magnesium, chlorides, sulphide, carbonates, nitrates, nitrites, heavy metals, and radioactive waste from nuclear reactor.
- Natural sources of pollution of water are soil erosion, leaching of minerals from rocks, and decaying of organic matter.
Water pollutants are categorized as point source pollution and non-point source pollution.
1. Point source pollution: When pollutants are discharged from a specific location such as a drain pipe carrying industrial effluents discharged directly into water body it represents point source pollution. In other words, point source pollution is defined as any single identifiable source of
pollution from which pollutants are discharged.
2. Non-Point source pollution: Those sources which do not have any specific location for discharging pollutants, in the water body are known as non-point sources of water pollution. For example, run off from agricultural fields, grazing lands, construction sites, abandoned mines and pits etc.
Effects of Water Pollution
Water pollution is the second major source of waterborne diseases and health problems after air pollution.
(i) Effects on humans
On consuming polluted water, humans can suffer from diseases like amoebic dysentery, skin cancers, cholera, typhoid fever, damage of nervous system, genetic mutations/ birth defects, hepatitis, malaria. Metals like lead, zinc, arsenic, copper, mercury and cadmium in industrial waste waters adversely affect humans and other animals. Consumption of arsenic polluted water leads to skin lesions, rough skin, dry and thickening of skin and ultimately skin cancer. Pollution of water bodies by mercury causes Minamata disease in humans and dropsy in fishes. Lead causes displexia; cadmium poisoning causes Itai – Itai disease etc.
(ii) Effects on plants and animals
Water pollution results in lower crop yields, excess growth of algae can kill aquatic life, reduce photosynthesis, disrupts the food chain and food web. Oil spills are a major problem near coastal waters and can kill or adversely affect fish, other aquatic organisms, and birds and mammals. Spills can kill or reduce populations of organisms living in coastal sands and rocks and may kill the worms and insects that serve as food to birds and other animals.
Fertilizers and pesticides are widely used in agriculture. Their excessive use to increase agricultural yield has led to the phenomenon of eutrophication and biomagnifications, which are serious consequences of water pollution.
- Eutrophication: With the use of high-yielding varieties of crops application of fertilizers and pesticides has increased. Excess fertilizers may mix with surface water bodies (surface runoff). The enrichment of water with nutrients such as nitrates and phosphates that triggers the growth of green algae is called eutrophication. This fast growth of algae followed by their decomposition depletes the water body of the dissolved oxygen. As a result, aquatic animals die of oxygen shortage.
- Biomagnification: Entry of harmful, non-biodegradable chemicals in small concentration and their accumulation in greater concentration in the various levels of a food chain is called biomagnification. Nonbiodegradable pesticides, such as DDT are widely used for crop protection. Once they enter the food chain, their concentration keeps on increasing with each trophic level (steps of a food chain). As a result, accumulation of these compounds takes place in the body of top consumers over a period of time.
Control measures for preventing water pollution
- Setting up effluent treatment plans to treat waste.
- Industrial wastes must be treated before discharge.
- Educate Public for preventing water pollution and the consequences of water pollution Strict enforcement of Water Pollution Control Act.
- Continuous monitoring of water pollution at different places.
- Developing economical method of water treatment.
Land pollution is the degradation of the earth’s land surface through misuse of the soil by poor agricultural practices, mineral exploitation, industrial waste dumping, and indiscriminate disposal of urban and toxic wastes. In simple terms, land pollution is the degradation of the earth’s surface caused by a misuse of resources and improper disposal of waste. Land pollution is responsible for damage done to natural habitat of animals, deforestation and damage done to natural resources, and the general uglying up of our communities. Polluting the land by harmful chemicals can lead to entry of pollutants into food chain. This is commonly caused by excess use of fertilizers in agriculture, irresponsible disposable of industrial wastes etc. Even defecating in the open spaces also causes pollution.
Sources of Land Pollution
The major sources of land pollution are highlighted below:
(i) Soil erosion: Soil erosion can be defined as the movement of topsoil from one place to another. Soil erosion removes rich humus topsoil developed over many years through vegetative decay and
microbial degradation and thus strips the land of valuable nutrients for crop growth. Strip mining for minerals and coal lays waste thousands of acres of land each year, denuding the earth and subjecting the mined area to widespread erosion problems. The increase in urbanization due to population pressure presents additional soil-erosion problems; sediment loads in nearby streams may increase as much as 500 to 1,000 times.
(ii) Industrial Waste: Large number of industrial chemicals, dyes, acids, fertilizer companies, pharmaceutical companies etc. find their way into the soil and are known to create many health
hazards including cancer.
(iii)Urban Wastes: Because of modem lifestyle and eating habits the urban wastes are becoming very dangerous to human beings. Urban wastes include both which is a nondegradable material and harmful to the society in long run.
(iv) Agricultural sources: Agricultural chemicals especially fertilizers and pesticides pollute the soil. Fertilizers in the runoff water from these fields can cause eutrophication in water bodies. Pesticides are highly toxic chemicals that affect humans and other animals adversely causing respiratory problems, cancer, and death.
(v)Plastic bags: Plastic bags made from low density polyethylene, is virtually indestructible, create colossal environmental hazard like land pollution. The discarded bags block drains and sewage
Effects of land pollution
- Toxic compounds affect plant growth and human life also.
- Water logging and salinity makes soil infertile.
- Hazardous chemicals enter into food chain from soil disturbing the biochemical process.
- Nervous disorders, gastrointestinal disorder, joint pain, respiratory problems are the effects seen on human beings.
Control measures for preventing soil pollution
1. Soil erosion must be prevented or controlled by proper tree plantation.
2. All the wastes from industry, domestic, must be dumped with proper treatment.
3. Use of synthetic fertilizers must be avoided instead natural fertilizers must be preferred.
4. Educate people regarding consequences of soil pollution and to prevent soil pollution.
5. Toxic and non-degradable materials must be totally banned.
6. Recycling and reuse of industrial and domestic wastes can minimize soil pollution considerably
Noise pollution has a relatively recent origin and is one of the least discussed problems. Noise is one of the most pervasive pollutant. People tend to underestimate this problem because it is not possible to smell, see or touch it. Noise Pollution is any loud sounds that are either harmful or annoying to humans and animals. To be more precise, noise by definition is “sound without value‖ or “any noise that is unwanted by the recipient”. Noise like other pollutants is a byproduct of industrialization, urbanization and modern civilization. Noise level is measured in terms of decibels (dB). W.H.O. has prescribed optimum noise level as 45 dB by day and 35 dB by night. Anything above 80 dB is hazardous.
Sources of Noise Pollution
Noise pollution is a growing problem. It is a composite of sounds generated by human activities ranging from blasting stereo systems to the roar of supersonic transport jets. All human activities contribute to noise pollution to varying extent. Noise pollution is more intense in the work environment than in the general environment. Sources of noise pollution are many and may be located indoors or outdoors.
(a) Indoor sources include noise produced by household gadgets like radio, television, generators, electric fans, washing machine, vacuum cleaners, air coolers, air conditioners and family conflict. The average background noise in a typical home today is between 40 and 50 decibels. Noise pollution is more in cities due to a higher concentration of population and industries and activities such as transportation.
(b) Outdoor sources of noise pollution include indiscriminate use of loudspeakers, industrial activities, automobiles, rail traffic, aeroplanes and activities such as those at market place, religious, social, and cultural functions, sports and political rallies. During festivals, marriage and many other occasions, use of fire crackers contribute to noise pollution.
Effects of Noise Pollution
The research shows that many illnesses are connected to noise pollution, such as hearing loss, high blood pressure, coronary heart diseases, loss of temper, and decrease in work efficiency, sleeplessness, anxiety, and speech interference. The effect is variable, depending upon individual susceptibility, duration of exposure, nature of noise, and time distribution of exposure. On average, an individual will experience a threshold shift (a shift in an individual’s upper limit of sound detectability) when exposed to noise levels of 75 to 80 dB for several hours. This shift will last only several hours once the source of noise pollution is removed. A second physiologically important level is the threshold of pain, at which even short-term exposure will cause physical pain (130 to 140 dB). Any noise sustained at this level will cause a permanent threshold shift or permanent partial hearing loss. At the uppermost level of noise (greater than 150 dB), even a single short-term blast may cause traumatic hearing loss and physical damage inside the ear. Industrial noises also affect the lives of animals. For example, whales‘ navigation system breaks down due to the sounds of ships.
Noise is everywhere, it is not as easy to control as other pollutions. Reducing noise pollution by muffling the sounds at the source is one of the best methods in industry and for urban living. Using earplugs where abnormal noise is produced. Banning noise polluting vehicles, controlling vibration of machines by proper lubricating machine, plantation of trees on road sides and near building can absorb noise, constructing sound proof rooms, enforcing noise pollution control act and educating people about noise pollution and its consequences. Creation of green cover adjacent to municipal roads and in mines is the way to mitigate noise pollution. It has been observed that noise level reduces by 10 decibels per every 10m wide green belt development.
Radiation pollution is one of the serious types of pollution and also neglected one. This is the pollution due to abnormal radiation in the environment. Radiation pollution is any form of ionizing or non-ionizing radiation that results from human activities. The radiations emanating from the decay of radioactive nuclides are major sources of radiation pollution. The most well-known radiation results from the detonation of nuclear devices and the controlled release of energy by nuclear-power generating plants, from the cell and mobile towers, by use of wireless Internet access modems, etc. Other sources of radiation include spent-fuel reprocessing plants, byproducts of mining operations, and experimental research laboratories. Increased exposure to medical X-rays and to radiation emissions from microwave ovens and other household appliances, although of considerably less magnitude, all constitute sources of environmental radiation.
Effects of Radiation Pollution
Public concern over the release of radiation into the environment greatly increased following the disclosure of possible harmful effects to the public from nuclear weapons testing, the accident (1979) at the Three Mile Island nuclear power generating plant near Harrisburg, and the catastrophic 1986 explosion at Chernobyl, A Soviet nuclear power plant. In the late 1980s, revelations of major pollution problems at U.S. nuclear weapons reactors raised apprehensions even higher. The environmental effects of exposure to high-level ionizing radiation have been extensively documented through post-war studies on individuals who were exposed to nuclear radiation in Japan. Some forms of cancer show up immediately.
Radioactive nuclear wastes cannot be treated by conventional chemical methods and must be stored in heavily shielded containers in areas remote from biological habitats. The safest of storage sites currently used are impervious deep caves or abandoned salt mines. Most radioactive wastes, however, have half-lives of hundreds to thousands of years, and to date no storage method has been found that is absolutely infallible.
Thermal pollution is the discharge of waste heat via energy dissipation into cooling water and subsequently into nearby waterways. In simple words, this pollution arises due to release of excess heat from thermal power plants, industries involved in metals molding etc. The heat is released into the surrounding air rising the temperature of the locality drastically. The major sources of thermal pollution are fossil-fuel and nuclear electric-power generating facilities and, to a lesser degree, cooling operations associated with industrial manufacturing, such as steel foundries, other primary metal manufacturers, and chemical and petrochemical producers.
Power plants- thermal and nuclear, chemical, and other industries use a lot of water (about 30 % of all abstracted water and 90 % of all water consumption excluding agricultural uses) for cooling purposes and the used hot water is discharged into rivers, streams, or oceans. Discharge of hot water may increase the temperature of the receiving water by 5 to 11 °C above the ambient water temperature. The discharge of heated water into a waterway often causes ecological imbalance, sometimes resulting in major fish kills near the discharge source. The increased temperature accelerates chemical-biological processes and decreases the ability of the water to hold dissolved oxygen. Unlike terrestrial ecosystems, the temperature of water bodies remains steady and does not change very much. Accordingly, aquatic organisms are adapted to a uniform steady temperature of the environment and any fluctuation in water temperature severely affects aquatic plants and animals. Hence discharge of hot water from power plants adversely affects aquatic organisms. Aquatic plants and animals in the warm tropical water live dangerously close to their upper limit of temperature, particularly during the warm summer months. It requires only a slight deviation from this limit to cause a thermal stress to these organisms. Discharge of hot water in water body affects feeding in fishes, increases their metabolism and affects their growth. Their swimming efficiency declines. Running away from predators or chasing prey becomes difficult. Their resistance to diseases and parasites decreases. Due to thermal pollution biological diversity is reduced. Thus rapid and dramatic changes in biologic communities often occur in the vicinity of heated discharges.
One of the best methods of reducing thermal pollution is to store the hot water in cooling ponds, allow the water to cool before releasing into any receiving water body.