Water Pollution

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Definition of Water Pollution

♣ The addition of sewage, industrial wastes, or other harmful or objectionable material to water in concentrations or in sufficient quantities to result in measurable degradation of water quality.

♣ The presence in water of enough harmful or objectionable material to damage water quality. Water solubility The maximum possible concentration of a chemical compound dissolved in water. Water storage pond An impound for liquid wastes designed to accomplish some degree of biochemical treatment. Water supply system The collection, treatment, storage, and distribution of water from source to consumer. Water table The surface of groundwater in the soil. Weir A spill over device used to measure or control water flows.

♣ The addition of harmful or objectionable material causing an alteration of water quality. ♣ Harmful or objectionable material in water in sufficient quantities to result in a measurable

degradation of the water quality. ♣ The presence in water of enough harmful or objectionable material to damage the water's

quality. ♣ The presence in water of enough harmful or objectionable material to damage the water's

quality. ♣ Industrial and institutional wastes, and other harmful or objectionable material in sufficient

quantities to result in a measurable degradation of the water quality. ♣ The impairment of water quality by agricultural, domestic or industrial wastes to a degree

that the natural water quality is changed to hinder any beneficial use of the water or render it offensive to the senses of sight, taste, or smell or when sufficient amounts of wastes create or pose a potential threat to human health or the environment.

♣ The degradation of a body of water by a substance or condition to such a degree that the water fails to meet specified standards or cannot be used for a specific purpose.

♣ The introduction of substances that make water impure compared with undisturbed water. Usually this comes from soil erosion, introduction of poisonous chemicals from industries and spills and introduction of domestic sewage or industrial and agricultural wastes.

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♣ a state of unhealthiness, impurity dirtiness of water caused by the deposition of harmful substances into the water.

♣ Generally, the presence in water of enough harmful or objectionable material to damage the water's quality. More specifically, pollution shall be construed to mean contamination of any waters such as will create or is likely to create a nuisance or to render such waters harmful, detrimental or injurious to public health, safety or welfare, or to domestic, municipal, commercial, industrial, agricultural, recreational, or other legitimate uses, or to livestock, wild animals, birds, fish or other aquatic life, including but not limited to such contamination by alteration of the physical, chemical or biological properties of such waters, or change in temperature, taste, color or order thereof, or the discharge of any liquid, gaseous, radioactive, solid or other substances into such waters. More simply, it refers to quality levels resulting from man's activities that interfere with or prevent water use or uses.

♣ Any substance or energy form (heat, light, noise, etc.) which alters the state of a body of water from what would naturally occur. Especially associated with those altered states which human value judgements have decreed as bad.

♣ The substances that cause harm to the water environment are called pollutants. Water pollutants both come from point sources and diffuse sources. Point sources are readily identifiable (e.g. domestic, urban, industrial wastes) compared with diffuse sources (e.g. agricultural or urban wastes via atmosphere - gaseous), making control easier in a perfectly regulated society. Monitoring freshwater pollution requires a thorough appreciation of the sources, pathways, and targets for a myriad of pollutants. It also means that we need to understand the dynamic processes occurring in the water ecosystems.

- Courtesy by : Google search engine.

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Sources of Water Pollution

Sewage is a major source of water pollution. Human excreta contains 400 different species of bacteria and viruses. Even well-treated sewage contains pathogenic bacteria and virus, unless properly chlorinated before being discharged into any water course. Sewage is a major contributor to water-borne diseases and affects the health of people and other organisms in the environment in many ways.

Industrial effluents from sugar factories, distilleries, tanneries and paper industries are accompanied by very high organic loads. By-products of paper and pulp industry cause depletion of fish upto as far as 40 km downstream. The wastes from oil refineries and steel industries contain phenol which imparts a strong odour, apart from poisoning the water body. Fertiliser industry wastes contain ammonia, urea, phosphate and sulphate which, in water, cause algal bloom and are toxic to aquatic fauna and flora. Alkaline industry wastes contain mercury which can kill human beings who consume mercurised fishes. Lead generated from battery, printing, petrol and paste-processing industries, trace and toxic elements such as zinc, copper etc., and effluents from mining industries are injurious to aquatic organisms.

Water in which maximum permissible concentration of any single or more constituents is in excess is unfit for drinking and human health. There are definite tolerance levels for water used for different activities such as drinking, bathing, irrigation and industrial purposes. Depending on its use, there are different physio-chemical and bacteriological standards for water.

Major water pollutants and their effect on human health

There are some ways in which bodies of water get polluted:

• Discharge of untreated domestic sewage into waterways. • Discharge of industrial effluents. • Discharge of agricultural wastes into waterways. • Use of pesticides, herbicides, fungicides and weedicides which seep into the ground water. • Discharge of fertilizer residues as run-off from farm lands into waterways. • Accidental spillage of oil in the seas by tankers.

- Courtesy by : C.P.R.Environmental Education Centre, Chennai

There are many causes for water pollution but two general categories exist: direct and indirect contaminant sources. Direct sources include effluent outfalls from factories, refineries, waste treatment plants etc.. that emit fluids of varying quality directly into urban water supplies. In the United States and other countries, these practices are regulated, although this doesn't mean that pollutants can't be found in these waters. Indirect sources include contaminants that enter the water supply from soils/groundwater systems and from the atmosphere via rain water. Soils and ground waters contain the residue of human agricultural practices (fertilizers, pesticides, etc..) and improperly disposed of industrial wastes. Atmospheric contaminants are also derived from human practices (such as gaseous emissions from automobiles, factories and even bakeries). Contaminants can be broadly classified into organic, inorganic, radioactive and acid/base.

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- Courtesy by : gdrc.org

The sources of water pollution also fall into one of two categories: point-source pollution and non-point-source pollution. The term point-source pollution refers to pollutants discharged from one discrete location or point, such as an industry or municipal wastewater treatment plant. Pollutants discharged in this way might include, for example, fecal coli form bacteria and nutrients from sewage, and toxics such as heavy metals, or synthetic organic contaminants.

The term non-point-source pollution refers to pollutants that cannot be identified as coming from one discrete location or point. Examples are oil and grease that enter the water with runoff from urban streets, nitrogen from fertilizers and pesticides, and animal wastes that wash into surface waters from agricultural lands. Natural and unknown causes of pollutants also can impact water quality and may be related to human activities. For example, highway or housing construction may help precipitate the runoff of natural pollution sources, such as sediment

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SOURCES PRESENT IN IMPAIRED SURFACE WATERS, 2002

RIVERS AND STREAMS LAKES AND RESERVOIRS

SOURCE % OF IMPAIRED MILES SOURCE % OF

IMPAIRED ACRES

Unknown Source 52% Atmospheric Deposition 72%

Unknown Nonpoint Source 51% Unknown Source 16%

Unknown Point Source 33% Unknown Nonpoint

Source 16%

Municipal Point Sources 23% Unknown Point

Source 12%

Agriculture 17% Natural Source 3%

Urban Runoff / Storm Sewers 17% Industrial Point

Source 2.5%

Natural Sources 13% Urban Runoff / Storm Sewers 2%

Industrial Point Sources 10%

Source Outside State Borders 9%

Confined Animal Feeding Operations Non-Point Source

7%

CAFO Point Source 7%

Crop-Related Source 7%

Hydromodification 7%

Irrigated Crop Production 6%

Flow Regulation 6%

Pollution is also caused when silt and other suspended solids, such as soil, wash off plowed fields, construction and logging sites, urban areas, and eroded river banks when it rains. Under natural conditions, lakes, rivers, and other water bodies undergo Eutrophication, an aging process that slowly fills in the water body with sediment and organic matter. When these sediments enter various bodies of water, fish respiration becomes impaired, plant productivity and water depth become reduced, and aquatic organisms and their environments become suffocated. Pollution in the form of organic material enters waterways in many different forms as sewage, as leaves and grass clippings, or as runoff from livestock feedlots and pastures. When natural bacteria and protozoan in the water break down this organic material, they begin to use up the oxygen dissolved in the water. Many types of fish and bottom-dwelling animals cannot survive when levels of dissolved oxygen drop below two to

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five parts per million. When this occurs, it kills aquatic organisms in large numbers which leads to disruptions in the food chain.

Three last forms of water pollution exist in the forms of petroleum, radioactive substances, and heat. Petroleum often pollutes water bodies in the form of oil, resulting from oil spills. Radioactive substances are produced in the form of waste from nuclear power plants, and from the industrial, medical, and scientific use of radioactive materials. Specific forms of waste are uranium and thorium mining and refining. The last form of water pollution is heat. Heat is a pollutant because increased temperatures result in the deaths of many aquatic organisms. These decreases in temperatures are caused when a discharge of cooling water by factories and power plants occurs.

- Courtesy by : University of Michigan,USA.

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Effects of Water Pollution

Pollution is not always visible. A river or lake may seem clean, but still be polluted. In groundwater, on which over one quarter of all Canadians rely for their water supply,

pollution is especially difficult to discern. Nor are the effects of pollution necessarily immediate; they may take years to appear.

When pollution makes water unsuitable for drinking, recreation, agriculture and industry, it eventually also diminishes the aesthetic quality of lakes and rivers. Even more seriously, when contaminated water destroys aquatic life and reduces its reproductive abilities, it eventually menaces human health. Nobody escapes the effects of water pollution.

Unfortunately, there are many effects of water pollution in the lakes and rivers. Many people and companies have dumped trash and waste products into the Great Lakes either accidentally and intentionally. These pollutants are often carried away by the current, but they do not disappear.

Some effects of water pollution include the following:

• Deformities of fish, birds, and other wildlife, sometimes leading to fish consumption advisories and even to complete loss of fish and wildlife habitat

• Taste and color differences in lake water, which can lead to restrictions placed on drinking water and swimming (beach closings)

• Raised and new added costs to agriculture and industry for clean-ups and other extra efforts • Death of beneficial microscopic organisms and the over-production of undesirable algae as

well as degradation of the lake bottom, which serves as a home for many types of organisms

Aquatic diseases and deformities As virtual "canaries in a gold mine," the deteriorating health of fish and wildlife speaks volumes about the need to clean up the Great Lakes. Heavy metals such as mercury and lead, and human-made organic chemicals such as pesticides, bio magnify as they move up the food chain, resulting in tumors and death for predatory animals, such as lake trout, herring gulls, and even humans.

Toxic pollutants can also alter the genetic makeup of an organism, resulting in either death or extreme deformities. Studies have found cormorants suffering from cross-billed syndrome at rates 42 percent times the natural occurrence, while terns exhibit birth defects from dioxin, PCBs and furan exposure at 31 times the normal levels. Other examples of deformities include large fish tumors and three-legged frogs.

Eutrophication: Before Europeans arrived in the Great Lakes region, the Great Lakes were mainly oligotrophic lakes, meaning they contained little plant nutrients and were continuously cool and clear due to their immense size and depth. Oligotrophic lakes can support high levels of animal life and receive proper amounts of nutrients, mainly phosphorous and nitrogen, from natural sources, such as decomposing plant matter.

European settlement and industrialization changed all of that. The amount of nutrients entering the Great Lakes has intensified greatly, mainly due to increased urbanization and agriculture, leading to increased biological growth, or eutrophication. Under eutrophic conditions, nutrient loading (more nutrients than the water body can handle) stimulates excessive plant growth, which in turn decreases the amount of oxygen in the water and eventually kills off certain species of animal life. Other

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pollution-tolerant species, such as worms and carp, grow more rapidly; thus, the ecological balance of the lake is significantly altered.

The effects of water pollution are not only devastating to people but also to animals, fish, and birds. Polluted water is unsuitable for drinking, recreation, agriculture, and industry. It diminishes the aesthetic quality of lakes and rivers. More seriously, contaminated water destroys aquatic life and reduces its reproductive ability. Eventually, it is a hazard to human health. Nobody can escape the effects of water pollution.

The other main effects are:

Spreads diseases: Polluted water is dangerous to human beings .People who drink polluted water are pruned to water borne diseases like cholera, typhoid, diarrhea. Affects vital body organs: Harmful chemicals in polluted water prevent the working of vital organs like heart and kidney. Kills aquatic life Spreads Disease Polluted water is dangerous to human health. People who drink polluted water become infected by waterborne diseases such as cholera, diarrhoea or typhoid. Causes Toxic Buildup in the Food Chain Harmful chemicals such pesticides from agriculture and heavy metals like lead and mercury from industries can build up in the food chain, where they reach toxic levels in fish and other sea animals. Kills Aquatic Life Polluted water kills fish, shrimp other aquatic life and coastal vegetation e.g. mangroves. This means fewer fish to eat and the loss of livelihood for many. Causes Algal Bloom Wastes such as urea, animal manure, vegetable peeling provide food for tiny plants called algae.The more waste there is the more algae grows, this is called algal bloom. Bacteria feed off rotting algae and in the process use up the oxygen in the water. Fish, crabs and shrimp then die because no oxygen is left in the water for them. Causes Flooding When a lot of soil is washed away into rivers and trenches this not only causes aquatic life to perish but also floods, especially with heavy rainfall. Water Weeds Runoff from agricultural lands results in the rapid growth of algae and waterweeds. These weeds make waterways impassible.

- Courtesy by : Great lakes commission, Ann arbor.

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Health Impacts of Water Pollution:

Human health issues:

Persistant Organic Pollutants, or POPs, such as dioxin, PCBs and DDT, are chemical substances that persist in the environment and bioaccumulate through the food web; therefore, POPs can also cause sickness and disease in humans, who are at the end of the food chain. People who regularly consume a lot of fish will have larger levels of toxic chemicals in their bodies than those who only eat fish occasionally. While scientists are still studying the effects of high chemical levels in humans, studies have suggested that toxic chemicals can lead to reproductive problems, cancer and neurological disorders.

People who are most at risk of health problems due to contaminated fish consumption are those with weakened

immune systems, including children, pregnant women and the elderly. Those in the "high-risk" category should either abstain from eating Great Lakes fish, or only eat one meal consisting of fish every week or month, depending on the type of fish. Each state/province in the Great Lakes region publishes a yearly fish advisory; of the 1,400 fish consumption advisories in the United States, more than 1,000 are found in the eight Great Lakes states.

Other human health issues related to water pollution include drinking water contamination and skin infection, caused by bacterial contamination.

It is a well-known fact that clean water is absolutely essential for healthy living. Adequate supply of fresh and clean drinking water is a basic need for all human beings on the earth, yet it has been observed that millions of people worldwide are deprived of this.

Freshwater resources all over the world are threatened not only by over exploitation and poor management but also by ecological degradation. The main source of freshwater pollution can be attributed to discharge of untreated waste, dumping of industrial effluent, and run-off from agricultural fields. Industrial growth, urbanization and the increasing use of synthetic organic substances have serious and adverse impacts on freshwater bodies. It is a generally accepted fact that the developed countries suffer from problems of chemical discharge into the water sources mainly

groundwater, while developing countries face problems of agricultural run-off in water sources. Polluted water like chemicals in drinking water causes problem to health and leads to water-borne diseases which can be prevented by taking measures can be taken even at the household level.

Groundwater and its contamination

Many areas of groundwater and surface water are now contaminated with heavy metals, POPs (persistent organic pollutants), and nutrients that have an adverse affect on health. Water-borne diseases and water-caused health problems are mostly due to inadequate and incompetent management of water resources. Safe water for all can only be assured when access, sustainability,

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and equity can be guaranteed. Access can be defined as the number of people who are guaranteed safe drinking water and sufficient quantities of it. There has to be an effort to sustain it, and there has to be a fair and equal distribution of water to all segments of the society. Urban areas generally have a higher coverage of safe water than the rural areas. Even within an area there is variation: areas that can pay for the services have access to safe water whereas areas that cannot pay for the services have to make do with water from hand pumps and other sources.

In the urban areas water gets contaminated in many different ways, some of the most common reasons being leaky water pipe joints in areas where the water pipe and sewage line pass close together. Sometimes the water gets polluted at source due to various reasons and mainly due to inflow of sewage into the source.

Ground water can be contaminated through various sources and some of these are mentioned below.

Pesticides. Run-off from farms, backyards, and golf courses contain pesticides such as DDT that in turn contaminate the water. Leechate from landfill sites is another major contaminating source. Its effects on the ecosystems and health are endocrine and reproductive damage in wildlife. Groundwater is susceptible to contamination, as pesticides are mobile in the soil. It is a matter of concern as these chemicals are persistent in the soil and water.

Sewage. Untreated or inadequately treated municipal sewage is a major source of groundwater and surface water pollution in the developing countries. The organic material that is discharged with municipal waste into the watercourses uses substantial oxygen for biological degradation thereby upsetting the ecological balance of rivers and lakes. Sewage also carries microbial pathogens that are the cause of the spread of disease.

Nutrients. Domestic waste water, agricultural run-off, and industrial effluents contain phosphorus and nitrogen, fertilizer run-off, manure from livestock operations, which increase the level of nutrients in water bodies and can cause eutrophication in the lakes and rivers and continue on to the coastal areas. The nitrates come mainly from the fertilizer that is added to the fields. Excessive use of fertilizers cause nitrate contamination of groundwater, with the result that nitrate levels in drinking water is far above the safety levels recommended. Good agricultural practices can help in reducing the amount of nitrates in the soil and thereby lower its content in the water.

Synthetic organics. Many of the 100 000 synthetic compounds in use today are found in the aquatic environment and accumulate in the food chain. POPs or Persistent organic pollutants, represent the most harmful element for the ecosystem and for human health, for example, industrial chemicals and agricultural pesticides. These chemicals can accumulate in fish and cause serious damage to human health. Where pesticides are used on a large-scale, groundwater gets contaminated and this leads to the chemical contamination of drinking water.

Acidification. Acidification of surface water, mainly lakes and reservoirs, is one of the major environmental impacts of transport over long distance of air pollutants such as sulphur dioxide from power plants, other heavy industry such as steel plants, and motor vehicles. This problem is more severe in the US and in parts of Europe.

Chemicals in drinking water

Chemicals in water can be both naturally occurring or introduced by human interference and can have serious health effects.

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Fluoride. Fluoride in the water is essential for protection against dental caries and weakening of the bones, but higher levels can have an adverse effect on health. In India, high fluoride content is found naturally in the waters in Rajasthan.

Arsenic. Arsenic occurs naturally or is possibly aggravated by over powering aquifers and by phosphorus from fertilizers. High concentrations of arsenic in water can have an adverse effect on health. A few years back, high concentrations of this element was found in drinking water in six districts in West Bengal. A majority of people in the area was found suffering from arsenic skin lesions. It was felt that arsenic contamination in the groundwater was due to natural causes. The government is trying to provide an alternative drinking water source and a method through which the arsenic content from water can be removed.

Lead. Pipes, fittings, solder, and the service connections of some household plumbing systems contain lead that contaminates the drinking water source.

Recreational use of water. Untreated sewage, industrial effluents, and agricultural waste are often discharged into the water bodies such as the lakes, coastal areas and rivers endangering their use for recreational purposes such as swimming and canoeing.

Petrochemicals. Petrochemicals contaminate the groundwater from underground petroleum storage tanks.

Other heavy metals. These contaminants come from mining waste and tailings, landfills, or hazardous waste dumps.

Chlorinated solvents. Metal and plastic effluents, fabric cleaning, electronic and aircraft manufacturing are often discharged and contaminate groundwater.

Disease

Water-borne diseases are infectious diseases spread primarily through contaminated water. Though these diseases are spread either directly or through flies or filth, water is the chief medium for spread of these diseases and hence they are termed as water-borne diseases.

Most intestinal (enteric) diseases are infectious and are transmitted through faecal waste. Pathogens – which include virus, bacteria, protozoa, and parasitic worms – are disease-producing agents found in the faeces of infected persons. These diseases are more prevalent in areas with poor sanitary conditions. These pathogens travel through water sources and interfuses directly through persons handling food and water. Since these diseases are highly infectious, extreme care and hygiene should be maintained by people looking after an infected patient. Hepatitis, cholera, dysentery, and typhoid are the more common water-borne diseases that affect large populations in the tropical regions.

A large number of chemicals that either exist naturally in the land or are added due to human activity dissolve in the water, thereby contaminating it and leading to various diseases.

Cause Water-borne diseases

Bacterial infections

Typhoid Cholera Paratyphoid fever Bacillary dysentery

Viral infections

Infectious Hepatitis (jaundice) Poliomyelitis

Protozoal infections

Amoebic dysentery

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Pesticides. The organophosphates and the carbonates present in pesticides affect and damage the nervous system and can cause cancer. Some of the pesticides contain carcinogens that exceed recommended levels. They contain chlorides that cause reproductive and endocrinal damage.

Lead. Lead is hazardous to health as it accumulates in the body and affects the central nervous system. Children and pregnant women are most at risk.

Fluoride. Excess fluorides can cause yellowing of the teeth and damage to the spinal cord and other crippling diseases.

Nitrates. Drinking water that gets contaminated with nitrates can prove fatal especially to infants that drink formula milk as it restricts the amount of oxygen that reaches the brain causing the ‘blue baby’ syndrome. It is also linked to digestive tract cancers. It causes algae to bloom resulting in eutrophication in surface water.

Petrochemicals. Benzene and other petrochemicals can cause cancer even at low exposure levels.

Chlorinated solvents. These are linked to reproduction disorders and to some cancers.

Arsenic. Arsenic poisoning through water can cause liver and nervous system damage, vascular diseases and also skin cancer.

Other heavy metals. –Heavy metals cause damage to the nervous system and the kidney, and other metabolic disruptions.

Salts. It makes the fresh water unusable for drinking and irrigation purposes.

Exposure to polluted water can cause diarrhoea, skin irritation, respiratory problems, and other diseases, depending on the pollutant that is in the water body. Stagnant water and other untreated water provide a habitat for the mosquito and a host of other parasites and insects that cause a large number of diseases especially in the tropical regions. Among these, malaria is undoubtedly the most widely distributed and causes most damage to human health.

Environmental contamination with methyl mercury:

Of late inorganic mercury is used in the industrial production of acetaldehyde. It is discharged into the nearby bay as waste water and was ingested by organisms in the bottom sediments. Fish and other creatures in the sea are soon contaminated and eventually residents of this area who consumed the fish suffered from MeHg (methyl mercury) intoxication, later known as the Minamata disease. The disease was first detected in 1956 but the mercury emissions continued until 1968. But even after the emission of mercury stopped, the bottom sediment of the polluted water contained high levels of this mercury.

Various measures were taken to deal with this disease. Environmental pollution control, which included cessation of the mercury process; industrial effluent control, environmental restoration of the bay; and restrictions on the intake of fish from the bay. This apart research and investigative activities were promoted assiduously, and compensation and help was offered by the Japanese Government to all those affected by the disease.

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The Minamata disease proved a turning point, towards progress in environment protection measures. This experience clearly showed that health and environment considerations must be integrated into the process of economic and industrial development from an early stage.

Oil pollution is a growing problem, particularly devastating to coastal wildlife. Small quantities of oil spread rapidly across long distances to form deadly oil slicks. In this picture, demonstrators with "oil-covered" plastic animals protest a potential drilling project in Key Largo, Florida. Whether or not accidental spills occur during the project, its impact on the delicate marine ecosystem of the coral reefs could be devastating

The below figure shows an aquatic animal being affected by oil contamination.

.

- Courtesy by : University of Michigan, USA.

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PREVENTION OF WATER POLLUTION

• Legislation should be enforced to control water pollution. • Effluents from industries should be treated and then discharged into water bodies. • Treated effluents can be recycled for other uses like agriculture, and the sludge after drying

can be used as manure. • Many more sewage treatment plants must be installed. At present, raw sewage is fed directly

into water bodies.

- Courtesy by : C.P.R.Environmental Education Centre, Chennai

Preventive measures

Water-borne epidemics and health hazards in the aquatic environment are mainly due to improper management of water resources. Proper management of water resources has become the need of the hour as this would ultimately lead to a cleaner and healthier environment.

In order to prevent the spread of water-borne infectious diseases, people should take adequate precautions. The city water supply should be properly checked and necessary steps taken to disinfect it. Water pipes should be regularly checked for leaks and cracks. At home, the water should be boiled, filtered, or other methods and necessary steps taken to ensure that it is free from infection.

Three options are available in controlling industrial wastewater. Control can take place at the point of generation in the plant; waste water can be pretreated for discharge to municipal treatment sources; or wastewater can be treated completely at the plant and either reused or discharged directly into receiving waters .The sewage water is made to undergo three treatments before disposing into the sea.

1.Primary treatment

2.Secondary treatment

3.Tertiary treatment.

The following figure illustrates it.

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In order to prevent the spread of water-borne infectious diseases, people should take adequate precautions. The city water supply should be properly checked and necessary steps taken to disinfect it. Water pipes should be regularly checked for leaks and cracks. At home, the water should be boiled, filtered, or other methods and necessary steps taken to ensure that it is free from infection.

A great deal can be done to minimize pollution if we take care to recycle materials whose production creates pollution and if we act responsibly with household chemicals and their disposal. Additionally, there are choices we make each day that also can affect the quantity of pollutants our actions will introduce into the environment. Heavily packaged foods, for instance, contain boxes, cartons, bottles etc.. made with polluting dyes, many of which are released from groundwater at municipal land fills. Whether we choose to drive to the corner store rather than walk or ride a bicycle will determine how much we personally contribute to acid and hydrocarbon emissions to the atmosphere (and ultimately to global fresh water supplies.

Finally it is in our hands to protect the world:

- Courtesy by : University of Michigan,USA.

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Links to Other Websites About Water Pollution

• http://www.umich.edu/~gs265/society/waterpollution.htm -- Water Pollution and Society.

• http://www.soest.hawaii.edu/GG/ASK/waterpol3.html -- Sources of Water Pollution. • http://www.ukrivers.net/pollution.html -- Finding out about Water Pollution • http://mbgnet.mobot.org/fresh/pollute.htm -- Types of Water Pollution • http://www.infoplease.com/ce6/sci/A0851609.html -- Contamination of water

resources by harmful wastes