ModI Env Pollution

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Module V

Environmental

Pollution


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Module V:Environmental Pollution

Definition

Causes, effects and control measures of:

Air pollution Water pollution

Soil pollution

Marine pollution

Noise pollution

Thermal pollution

Nuclear pollution

Solid waste management: Causes, effects and control measures of urbanand industrial wastes.

Role of an individual in prevention of pollution.

Pollution case studies.

Disaster management: floods, earthquake, cyclone and landslides.


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Causes of Pollution

Until relatively recently in humanity's history, where pollution has existed,it has been primarily a local problem. The industrialization of society, theintroduction of motorized vehicles, and the explosion of the humanpopulation, however, have caused an exponential growth in theproduction of goods and services. Coupled with this growth has been atremendous increase in waste by-products. The indiscriminate discharge

of untreated industrial and domestic wastes into waterways, the spewingof thousands of tons of particulates and airborne gases into theatmosphere, the "throwaway" attitude toward solid wastes, and the use ofnewly developed chemicals without considering potential consequenceshave resulted in major environmental disasters, including the formation ofsmog in the Los Angeles area since the late 1940s and the pollution oflarge areas of the Mediterranean Sea. Technology has begun to solvesome pollution problems (see pollution control), and public awareness ofthe extent of pollution will eventually force governments to undertakemore effective environmental planning and adopt more effectiveantipollution measures.


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Causes of Pollution

During the industrial revolution of thenineteenth century, the mass production ofgoods created harmful wastes, much of which

was dumped into rivers and streams. Thetwentieth century saw the popular acceptanceof the automobile and the internalcombustion engine, which led to the pollution

of the air. Rapidly expanding urban centersbegan to use rivers and lakes as repositoriesfor sewage.


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Land pollution/Soil Pollution

Land pollution involves the depositing of solid wastes that areuseless, unwanted, or hazardous.

Land pollution is the degradation of the Earth's land surfacethrough misuse of the soil by poor agricultural practices, mineral

exploitation, industrial waste dumping, and indiscriminate disposalof urban wastes.

Land pollution also involves the accumulation of chemicals in theground. Modern agriculture, which has grown dependent onchemical fertilizers and chemicals that kill insects, has introducedsubstances into the soil that kill more than pests. For many yearsthe chemical DDT was routinely sprayed on crops to control pests. Itwas banned when scientists discovered that the chemical enteredthe food chain and was harming wildlife and possibly humans.


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Types of solid waste include garbage, rubbish,

ashes, sewage-treatment solids, industrial

wastes, mining wastes, and agricultural

wastes.


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Causes of Soil Pollution

Soil MisuseSoil erosion--a result of poor agricultural practices--removes richhumus topsoil developed over many years through vegetative decayand microbial degradation and thus strips the land of valuablenutrients for crop growth. Strip mining for minerals and coal lays

waste thousands of acres of land each year, denuding the Earth andsubjecting the mined area to widespread erosion problems. Theincreases in urbanization due to population pressure presentsadditional soil-erosion problems; sediment loads in nearby streamsmay increase as much as 500 to 1,000 times over that recorded innearby undeveloped stretches of stream. Soil erosion not only

despoils the Earth for farming and other uses, but also increases thesuspended-solids load of the waterway. This increase interfereswith the ecological habitat and poses silting problems in navigationchannels, inhibiting the commercial use of these waters.


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Solid Waste is the municipal wastes that is, thesolid wastes sent by households, business, andmunicipalities Additional solid wastes accumulate

from mining, industrial production, andagriculture. Although municipal wastes are themost obvious, the accumulations of other typesof wastes, the accumulations of other types of

waste are far greater, in many instances are moredifficult to dispose of, and present greaterenvironmental hazards.


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Control Measures of Soil Pollution

Solid wastes are compacted in the landfill and are vented toeliminate the buildup of dangerous gases. Hazardouswastes, including toxic chemicals and flammable,radioactive, or biological substances, cannot be depositedin landfills, and the management of these wastes is subject

to federal and state regulation. Modern landfills attempt to minimize pollution of surface

and groundwater. They are now located in areas that willnot flood and that have the proper type of soil.

While most solid waste is buried in sanitary landfills. Asmall percentage of municipalities incinerate their refuse,while composting is rarely employed.


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Solid waste pollution has also been reduced byrecovering resources rather than burying them.Resource recovery includes massive systems that

burn waste to produce steam, but it also includesthe recycling of glass, metal, and paper fromindividual consumers and businesses. Theelimination of these kinds of materials from

landfills has prevented pollution and extendedthe period during which landfills can receivewaste.


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Drawbacks of landfills

Often, however, industrial wastes of unknowncontent are commingled with domestic wastes.Groundwater infiltration and contamination ofwater supplies with toxic chemicals have recently

led to more active control of landfills andindustrial waste disposal. Careful management ofsanitary landfills, such as providing for leachateand runoff treatment as well as daily coverage

with topsoil, has alleviated most of the problemsof open dumping. In many areas, however, spacefor landfills is running out and alternatives mustbe found


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Recycling of materials is practical to some extent formuch municipal and some industrial wastes, and asmall but growing proportion of solid wastes is beingrecycled. When wastes are commingled, however,

recovery becomes difficult and expensive. Newprocesses of sorting ferrous and nonferrous metals,paper, glass, and plastics have been developed, andmany communities with recycling programs nowrequire refuse separation. Crucial issues in recycling are

devising better processing methods, inventing newproducts for the recycled materials, and finding newmarkets for them.


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ncineration is another method for disposing of solidwastes. Advanced incinerators use solid wastes as fuel,burning quantities of refuse and utilizing the resultantheat to make steam for electricity generation. Wastes

must be burned at very high temperatures, andincinerator exhausts must be equipped withsophisticated scrubbers and other devices for removingdioxins and other toxic pollutants. Problems remain,however: incinerator ash contains high ratios of heavy

metals, becoming a hazardous waste in itself, and high-efficiency incinerators may discourage the use ofrecycling and other waste-reduction methods.


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Composting is increasingly used to treat some

agricultural wastes, as well as such municipal

wastes as leaves and brush. Composting

systems can produce usable soil conditioners,or humus, within a few months


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AIR POLLUTION

AIR POLLUTIONAir pollution is the accumulation in theatmosphere of substances that, in sufficientconcentrations, endanger human health or

produce other measured effects on living matterand other materials. Among the major sources ofpollution are power and heat generation, theburning of solid wastes, industrial processes, and,

especially, transportation. The six major types ofpollutants are carbon monoxide, hydrocarbons,nitrogen oxides, particulates, sulfur dioxide, andphotochemical oxidants.


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Local , Regional and Global

Air pollution on a regional scale is in part the result of local airpollution--including that produced by individual sources, such asautomobiles--that has spread out to encompass areas of manythousands of square kilometers. Meteorological conditions and

landforms can greatly influence air-pollution concentrations at anygiven place, especially locally and regionally. For example, citieslocated in bowls or valleys over which atmospheric inversions formand act as imperfect lids are especially likely to suffer fromincidences of severe smog. Oxides of sulfur and nitrogen, carriedlong distances by the atmosphere and then precipitated in solution

as acid rain, can cause serious damage to vegetation, waterways,and buildings.


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GlobalHumans also pollute the atmosphere on a global scale,Measurements suggest that the concentration of carbon dioxide inthe atmosphere is increasing at a rate of about 0.2% every year. Theeffect of this increase may be to alter the Earth's climate byincreasing the average global temperature.

Certain pollutants decrease the concentration of ozone occurringnaturally in the stratosphere, which in turn increases the amount ofultraviolet radiation reaching the Earth's surface. Such radiationmay damage vegetation and increase the incidence of skin cancer.Examples of stratospheric contaminants include nitrogen oxidesemitted by supersonic aircraft propellants. The chlorofluorocarbons

reach the stratosphere by upward mixing from the lower parts ofthe atmosphere . It is believed that these chemicals are responsiblefor the noticeable loss of ozone over the polar regions that hasoccurred in the 1980s.


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Causes of Air Pollution

As a coal economy has gradually been replaced by apetroleum economy, photochemical smog has becomepredominant in many cities. Its unpleasant propertiesresult from the irradiation by sunlight of hydrocarbons

(primarily unburned gasoline emitted by automobilesand other combustion sources) and other pollutants inthe air. Irradiation produces a long series ofphotochemical reactions .The products of the reactionsinclude organic particles, ozone, aldehydes, ketones,

peroxyacetyl nitrate, and organic acids and otheroxidants. Sulfur dioxide, which is always present tosome extent, oxidizes and hydrates to form sulfuricacid and becomes part of the particulate matter.


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Furthermore, automobiles are polluters even in theabsence of photochemical reactions. They areresponsible for much of the particulate material in theair; they also emit carbon monoxide, one of the most

toxic constituents of smog. Smog has seriously affected more persons than any

other type of air pollution. It can be loosely defined asa multisource, widespread air pollution that occurs inthe air of cities. Smog, a contraction of the words

smoke and fog, has been caused throughout recordedhistory by water condensing on smoke particles,usually from burning coal.


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Effects of Air Pollutants

All types of smog decrease visibility and, with thepossible exception of ice fog, are irritating to therespiratory system. Statistical studies indicatethat smog is a contributor to malignancies of

many types. Photochemical smog produces eyeirritation and lacrimation and causes severedamage to many types of vegetation, includingimportant crops. Acute effects include an

increased mortality rate, especially amongpersons suffering from respiratory and coronaryailments. Air pollution also has a deleteriouseffect on works of art .


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Control Measures of Air Pollution

Automobile emission control systems have

been created and improved to meet more

stringent air quality standards. Coal-burning

electric power plants have been required toinstall filtration systems on their smokestacks,

and manufacturing facilities have had to install

equipment that "scrubs" polluted air clean


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WATER POLLUTION

WATER POLLUTIONWater pollution is the introduction into fresh orocean waters of chemical, physical, or biological

material that degrades the quality of the waterand affects the organisms living in it. This processranges from simple addition of dissolved orsuspended solids to discharge of the most

insidious and persistent toxic pollutants (such aspesticides, heavy metals, and nondegradable,bioaccumulative, chemical compounds).


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Water Pollutionhas existed longer than any othertype of pollution. Depositing liquid and solidwastes in rivers, streams, lakes, and oceans was

convenient and inexpensive for a company ormunicipality, but it eventually destroyed theecosystems found in the water. Many large riversbecame nothing more than sewers. Most

troubling was the polluting of groundwater,creating serious health hazards for those peoplewho drank water containing toxic substances.
http://legal-dictionary.thefreedictionary.com/Water+Pollutionhttp://legal-dictionary.thefreedictionary.com/Water+Pollution


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Conventional

Non conventional

Thermal


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ConventionalConventional or classical pollutants are generally associatedwith the direct input of (mainly human) waste products.Rapid urbanization and rapid population increase haveproduced sewage problems because treatment facilities

have not kept pace with need. Untreated and partiallytreated sewage from municipal wastewater systems andseptic tanks in unsewered areas contribute significantquantities of nutrients, suspended solids, dissolved solids,oil, metals (arsenic, mercury, chromium, lead, iron, and

manganese), and biodegradable organic carbon to thewater environment.


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The nonconventional pollutants include dissolved andparticulate forms of metals, both toxic and nontoxic,and degradable and persistent organic carboncompounds discharged into water as a by-product of

industry or as an integral part of marketable products.More than 13,000 oil spills of varying magnitude occurin the United States each year. Thousands ofenvironmentally untested chemicals are routinelydischarged into waterways; an estimated 400 to 500

new compounds are marketed each year. In addition,coal strip mining releases acid wastes that despoil thesurrounding waterways.


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Nonconventional pollutants vary from biologicallyinert materials such as clay and iron residues tothe most toxic and insidious materials such ashalogenated hydrocarbons (DDT, kepone, mirex,

and polychlorinated biphenyls--PCB). The lattergroup may produce damage ranging from acutebiological effects (complete sterilization ofstretches of waterways) to chronic sublethal

effects that may go undetected for years. Thechronic low-level pollutants are proving to be themost difficult to correct and abate because oftheir ubiquitous nature and chemical stability.


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Thermal pollution is the discharge of waste heat via energydissipation into cooling water and subsequently into nearbywaterways. The major sources of thermal pollution arefossil-fuel and nuclear electric-power generating facilitiesand, to a lesser degree, cooling operations associated with

industrial manufacturing, such as steel foundries, otherprimary-metal manufacturers, and chemical andpetrochemical producers.

The discharge temperatures from electric-power plantsgenerally range from 5 to 11 C degrees (9 to 20 F degrees)

above ambient water temperatures. An estimated 90% ofall water consumption, excluding agricultural uses, is forcooling or energy dissipation.


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The discharge of heated water into a waterwayoften causes ecological imbalance, sometimesresulting in major fish kills near the dischargesource. The increased temperature accelerates

chemical-biological processes and decreases theability of the water to hold dissolved oxygen.Thermal changes affect the aquatic system bylimiting or changing the type of fish and aquatic

biota able to grow or reproduce in the waters.Thus rapid and dramatic changes in biologicalcommunities often occur in the vicinity of heateddischarges.


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RADIATION POLLUTION

RADIATION POLLUTIONRadiation pollution is any form of ionizing or nonionizingradiation that results from human activities. The most well-known radiation results from the detonation of nucleardevices and the controlled release of energy by nuclear-

power generating plants (see nuclear energy). Othersources of radiation include spent-fuel reprocessing plants,by-products of mining operations, and experimentalresearch laboratories. Increased exposure to medical X raysand to radiation emissions from microwave ovens and

other household appliances, although of considerably lessmagnitude, all constitute sources of environmentalradiation.


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effects of exposure

The environmental effects of exposure to high-level ionizing radiation have been extensivelydocumented through postwar studies onindividuals who were exposed to nuclear

radiation in Japan. Some forms of cancer show upimmediately, but latent maladies of radiationpoisoning have been recorded from 10 to 30years after exposure. The effects of exposure to

low-level radiation are not yet known. A majorconcern about this type of exposure is thepotential for genetic damage.


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Control Measures

Radioactive nuclear wastes cannot be treatedby conventional chemical methods and mustbe stored in heavily shielded containers in

areas remote from biological habitats. Thesafest of storage sites currently used areimpervious deep caves or abandoned saltmines. Most radioactive wastes, however,

have half-lives of hundreds to thousands ofyears, and to date no storage method hasbeen found that is absolutely infallible.


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NOISE POLLUTIONNoise pollution has a relatively recent origin. It is acomposite of sounds generated by human activities rangingfrom blasting stereo systems to the roar of supersonictransport jets. Although the frequency (pitch) of noise may

be of major importance, most noise sources are measuredin terms of intensity, or strength of the sound field. Thestandard unit, one decibel (dB), is the amount of sound thatis just audible to the average human. The decibel scale issomewhat misleading because it is logarithmic rather than

linear; for example, a noise source measuring 70 dB is 10times as loud as a source measuring 60 dB and 100 times asloud as a source reading 50 dB.


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Noise may be generally associated with industrialsociety, where heavy machinery, motor vehicles, andaircraft have become everyday items. Noise pollution ismore intense in the work environment than in the

general environment, although ambient noiseincreased an average of one dB per year during the1980s. The average background noise in a typical hometoday is between 40 and 50 decibels. Some examples

of high-level sources in the environment are heavytrucks (90 dB at 15 m/50 ft), freight trains (75 dB at 15m/50 ft), and air conditioning (60 dB at 6 m/20 ft).


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The most readily measurable physiological effect ofnoise pollution is damage to hearing, which may beeither temporary or permanent and may causedisruption of normal activities or just generalannoyance. The effect is variable, depending uponindividual susceptibility, duration of exposure, natureof noise (loudness), and time distribution of exposure(such as steady or intermittent). On the average anindividual will experience a threshold shift (a shift in an

individual's upper limit of sound detectability) whenexposed to noise levels of 75 to 80 dB for severalhours. This shift will last only several hours once thesource of noise pollution is removed.


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Effects

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 causea permanent threshold shift or permanent

partial hearing loss. At the uppermost level of

noise (greater than 150 dB), even a singleshort-term blast may cause traumatic hearing

loss and physical damage inside the ear.


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Although little hard information is available on

the psychological side effects of increased

noise levels, many researchers attribute

increased irritability, lower productivity,decreased tolerance levels, increased

incidence of ulcers, migraine headaches,

fatigue, and allergic responses to continuedexposures to high-level noises in the

workplace and the general environment.


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The federal Clean Water Act (CWA) was originallyenacted in 1972 and then amended in 1977 and1987 (33 U.S.C.A. 12511387; Pub. L. No. 95-217 [1977 amendments]; Pub. L. No. 100-4 [1987

amendments]). The CWA seeks to eliminate the"discharge of pollutants into navigable waters," tomake water safe for people to fish and swim in,and to end the "discharges of toxic pollutants in

toxic amounts." The CWA seeks to accomplishthese goals through a variety of regulatorystrategies.


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