As a result it plays important roles in ecosystem support, economic development, cultural values and community well-being. Dozens of times a day those of us who live in the industrialized nations of the world enjoy a blessing denied to 75 percent of the world population: abundant supplies of clean water. But water is essential for life on earth. No known organisms can live without it. For centuries water has been used as a dumping ground for human sewage and industrial wastes. Added to them are the materials leached out and transported from and by water percolating through the soil and running off its surface to aquatic ecosystems.
Water pollution is degradation of water quality. Any physical, chemical, or biological change in water quality that adversely affects living organisms or makes water unsuitable for desired use can be considered pollution. Thus the term water pollution refers to – “Water contamination by a variety of chemical substances or transportation caused by several nutrients and fertilizers. ” – Southwest, 1 976 U. S. Department of Health Education and Welfare defines water pollution as – “The adding to water of any substance or he changing of water’s physical and chemical characteristics in any way which interferes with its use of legitimate purposes”.
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At present, water pollution is a major global problem. Everyday many people are dying for water pollution. Now water pollution becomes the leading cause of death & diseases. 3 1. 2 Sources of Water Pollution : There are many sources of water pollution. But before knowing that, we need to know that what are the sources of water, and then we will understand how they are becoming polluted. We get water from two sources – Surface Water Ground Water Surface Water is fresh water mound on Earth’s surface in streams and rivers, lakes, ponds, reservoirs.
Surface waters are replenished by the runoff of precipitation from the land and are therefore considered a renewable, although finite resource. Ground Water refers to the fresh water under Earth’s surface that is stored in aquifers. This water originates as rain or melting snow that seeps into the soil and finds its way down through cracks and spaces in sand, gravel or rock until it is stopped by an impenetrable layer, there it accumulates as groundwater. Surface water and groundwater have often been studied and managed as operate resources, although they are interrelated. Surface water seeps through the soil and becomes groundwater.
Conversely, groundwater can also feed surface water sources. Sources of surface water pollution are generally grouped into two categories based on their origin. Point Sources Non-point Sources Point source water pollution refers to contaminants that enter a waterway from a single, identifiable source, such as a pipe or ditch. Examples of sources in this category include discharges from a sewage treatment plant, a factory, or a city storm drain. Point source water pollution re easily findable. So, people can easily control them. Non-point source pollution refers to diffuse contamination that does not originate from a single discrete source.
Non-point source pollution is often the cumulative effect of small amounts of contaminants gathered from a large area. A common example is the leaching out of nitrogen compounds from fertilized agricultural lands. Nutrient runoffs in storm water from “sheet flow” over an agricultural field or a forest are also cited as examples of Non-point source pollution. 4 Surface Water Pollution : Surface water bodies are extensively used for espousal of untreated industrial wastes and this is one of the main sources of surface water pollution.
Surface water pollution is caused by – C Domestic Waste : Water pollution Of domestic is mainly caused by sewage. Sewage is defined as the waterborne waste derived from home, animal or food processing plants and includes human excreta, soaps, organic materials, different types of solids, waste food, oil detergents, paper and cloth. They are the largest group of water pollutants. Water pollution is caused by uncontrolled dumping of waste collected from villages, towns and cities into ponds, streams, lakes and rivers. C] Industrial Effluent : The discharge of industrial effluents into the water body caused water pollution.
These effluents contain a wide variety of inorganic and organic substances such as oils, greases, plastics, plasticizer, metallic wastes, suspended solids, phenols, pesticides, heavy metals and acids. Major industries of the country are located on or near the coastline or riversides. Organic substances deplete the oxygen content. Inorganic substances render the water unfit for drinking and other purposes. Acids and alkalis adversely effect the growth of fish and other aquatic organisms. Oil and other greasy substances interfere with the self purification mechanism of water. Urban runoff : Urban runoff is surface runoff of rainwater created by arbitration. This runoff is one of the major sources of water pollution in many urban communities worldwide. The porous and varied terrain of natural landscapes like forests, wetlands, and grasslands trap rainwater and snowbell and allow it to slowly filter into the ground. Runoff tends to reach receiving waters gradually. In contrast, nonporous urban landscapes like roads, bridges, parking lots, and buildings don’t let runoff slowly percolate into the ground… Arbitration also increases the variety and amount of pollutants transported to receiving waters.
Sediment from development and new construction; Oil, grease, and toxic chemicals from automobiles; nutrients and pesticides from turf management and gardening; viruses and bacteria from failing septic systems; road salts; and heavy metals are examples of pollutants generated in urban areas. Sediments and solids constitute the largest volume of pollutant loads to receiving waters in urban areas. њ Agricultural runoff : Water pollution can be caused by agricultural wastes such as fertilizers, pesticides, soil additives and animal wastes that are washed off from the land to the aquatic system through irrigation, rainfall and leaching. Oil pollution : There are about 15 million water crafts on navigable waters throughout the world. Their combined waste discharges are equivalent to a city with a population of 2,000,000. Thus oil pollution, an oxygen demanding Waste, is of concern not only from sensational major spills from ships and offshore drilling rigs but also from small spills and cleaning operations. Al Chemical Use : Industrial and agricultural work involves the use of many different chemicals that can run-off into water and pollute it. It can also cause health hazards to human body and many animals and fishes are dying for these chemicals.
CLC Thermal Pollution : An increase in the optimum water temperature by industrial processes (steel factories, electric power houses and atomic power plants) may be called as thermal pollution. Many industries generate their own power and use water to cool their generators. This hot water is released into the system from where it was drawn, causing a warming trend of surface waters. Fifth system is poorly flushed, a permanent increase in the temperature may result. However, if the water is released into he well flushed systems, permanent increase in temperature does not occur.
Many organisms are killed instantly by the hot water resulting into a high mortality. It may bring other disturbance in the ecosystem. The eggs of fish may hatch early or fail to hatch at all. It may lead to unplanned migration of aquatic animals. D Sediments : Sediment is defined as particles derived from soil or rocks that are transported by water or wind. The erosion of land surfaces and stream banks produces sediment. Sediment threatens water supplies and recreation and cause harm to plant and fish communities. Sediment can also be discharged from multiple different sources.
Sources include construction sites agricultural fields, stream banks, and highly disturbed areas. D Salinity Intrusion : Saltwater intrusion is a major problem in coastal regions all over the world, as it threatens the health and possibly lives Of many people who live in these areas. It increases the salinity of groundwater and water may become unsuitable for human use. Colonization of groundwater is considered a special category of pollution that threatens groundwater resources, because mixing a small quantity of saltwater in the rainwater makes freshwater unsuitable and can result in abandonment of freshwater supply.
CLC Accidental Spills of Chemicals : Accidental spills of environmentally harmful materials can happen anywhere and anytime, polluting land and water. Even echo-friendly cleaners and chemicals can harm the fish, plants and insects in our streams and harbors, if they are washed into stemware drains. 6 Ground Water Pollution : A lot of the Earth’s water is found underground in soil or under rock structures called aquifers. Humans often use aquifers as a means to obtain drinking water, and build wells to access it. When this water becomes polluted it is called groundwater pollution.
Groundwater pollution is often caused by pesticide contamination from the soil, this can infect Our drinking water and cause huge problems. Ground water pollution caused BBC Waste disposal site : Domestic and industrial wastes are collected to dispose them in a place. There are many chemicals which are found in these wastes. The places where these waste are disposed become polluted. If the place has a leak and it lead to the nearby river, then by the leaks, the chemicals go to the river and make the river polluted.
D Pesticides : Run-off from farms, skyward, and golf courses contain pesticides such as EDT that in turn contaminate the water. Leech ate 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. L] 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 s 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. C 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 transportation in the lakes and rivers and continue on to the coastal areas.
The nitrates come mainly from the fertilizer hat 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. 7 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 sulfur 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. C] Synthetic organics : Many of the 100 DO synthetic compounds in use today are found in the aquatic environment and accumulate in the food chain. 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. њ Arsenic Problem :
Most arsenic enters water supplies either from natural deposits in the earth or from industrial and agricultural pollution. Arsenic is a natural element of the earth’s crust. It is used in industry and agriculture and for other purposes. It also is a byproduct of copper smelting, mining and coal burning. C Suspended Matter : Some pollutants do not dissolve in water as their molecules are too big to mix between the water molecules. This material is called particulate matter and can often be a cause of water pollution. The suspended particles eventually settle and cause thick silt at the bottom.
This s harmful to marine life that lives on the floor of rivers or lakes. Biodegradable substances are often suspended in water and can cause problems by increasing the amount of anaerobic microorganisms present. Toxic chemicals suspended in water can be harmful to the development and survival of aquatic life. 8 1. 3 Common Contaminants of Water Pollution : There are some contaminants of water pollution. They are – C Infectious Agents : Disease causing agents or pathogens, including bacteria, viruses, protozoa, parasites. These come from raw sewage and animal waste and they may be responsible for 80% of the asses in developing countries.
CLC Oxygen demanding wastes : Reduce Dissolved Oxygen level in the water and affect aquatic life. Sewage, animal manure or biodegradable organic wastes are that type of waste. 0 Inorganic chemicals : Water-soluble acids, toxic compound, salt and metals are the inorganic chemicals. They make water unfit to consume and use for irrigation. Also can harm organisms and cause material corrosion. D Organic chemicals : Organic chemicals are petroleum products, oil, gasoline, plastics, pesticides, solvents, detergents. Presence of organic chemicals in water cause health kiss to humans and other organisms. ј Plant nutrients : Nitrates, phosphates, ammonium from fertilizers are plant nutrients. Excessive algal and plant growth lower the oxygen levels when they decompose. Sediment : Sediments are bad for aquatic animals. Mud, silt, sand are the example. Sediment disrupts photosynthesis and transports large amounts of other adsorbed pollutants. Sediments are bad for Aquatic animals. D Radio-active materials : Radon, uranium, Iodine, cesium, thorium, and tritium are the radio-active materials. These materials may come either from natural or anthropogenic sources.
Heat : Heat comes from cooling water for power plants & other industrial plants. Heat lowers the solubility of oxygen in water and it also affects aquatic lives directly. 9 1. 4 Health Hazards Caused by Water Pollution : Virtually all types of water pollution are harmful to the health of humans and animals. Water pollution may not damage our health immediately but can be harmful after long term exposure. Different forms of pollutants affect the health of animals in different ways. Such as Heavy metals from industrial processes can accumulate in nearby lakes and rivers.
These are toxic to marine life such as sis and shellfish, and subsequently to the humans who eat them. Heavy metals can slow development; result in birth defects and some are carcinogenic. Industrial waste often contains many toxic compounds that damage the health of aquatic animals and those who eat them. Some of the toxins in industrial waste may only have a mild effect whereas other can be fatal. They can cause immune suppression, reproductive failure or acute poisoning. Microbial pollutants from sewage often result in infectious diseases that infect aquatic life and terrestrial life through drinking water.
Microbial water pollution is a major problem in the developing world, with diseases such as cholera and typhoid fever being the primary cause of infant mortality. Organic matter and nutrients causes an increase in aerobic algae and depletes oxygen from the water column. This causes the suffocation of fish and other aquatic organisms. Sulfate particles from acid rain can cause harm the health of marine life in the rivers and lakes it contaminates, and can result in mortality. Suspended particles in freshwater reduces the quality of drinking water for humans and the aquatic environment for marine life.
Suspended particles can often reduce the amount of sunlight penetrating the water, disrupting the growth of photosynthetic plants and micro-organisms. There are some water borne diseases of human which caused by drinking or using polluted water. They are given pillowcase Bacterial infections Viral infections Protozoan infections Hellishness infection Diseases Typhoid, cholera, Paratyphoid fever, Dysentery Infectious Hepatitis (jaundice), Poliomyelitis Amoebic dysentery Roundworm, Hookworm, threadbare 10 2. 0 Global Warming 2. What is Global Warming : Global warming is defined s a natural or human induced increase in the average global temperature of the atmosphere near the Earth’s surface. The temperature at or near the surface of the Earth is determined by four main factors : ; ; ; ; The amount of sunlight Earth receives. The amount of sunlight Earth reflects. Retention of heat by the atmosphere. Evaporation and condensation of water vapor. In the last 100 years, Earth’s average surface temperature increased by about 0. 8 co (1. 4 OF). Two thirds of the increase occurred over the last three decades.
Warming of the climate system is unequivocal. Scientists are more Han 90% certain that most of it is caused by increasing concentrations of greenhouse gases produced by human activities. These findings are recognized by the national science academies of all the major industrialized countries. 11 2. 2 Causes of Global Warming : Scientists have spent decades figuring out what is causing global warming. They’ve looked at the natural cycles and events that are known to influence climate. But the amount and pattern of warming that’s been measured can’t be explained by these factors alone.
The only way to explain the pattern is to include the effect of greenhouse gases emitted by humans. There are many natural causes of global warming. But they do not warm much the planet. The most serious type of warm is anthropogenic which is created by humans. One of the first things scientists learned is that there are several greenhouse gases responsible for warming and humans emit them in a variety of ways. The causes of global warming are given below -?? Greenhouse Gases : Sunlight that reaches Earth warms both the atmosphere and the surface.
Earth’s surface and atmospheric system then irradiate heat as infrared radiation. Certain gases in Earth’s atmosphere absorb and re-emit this radiation. Some of it returns to the Earth ;s surface, making Earth warmer than it otherwise would be. In trapping heat, the gases act a little like the panes of glass in a greenhouse (although the process by which the heat is trapped is not the same as in a greenhouse), accordingly, the effect is called the greenhouse effect, and the gases which include Water vapor, carbon dioxide, methane, and chlorofluorocarbons (CIFS) are called greenhouse gases. Extra Carbon Dioxide Release : Human are releasing Carbon dioxide in the environment by burning fossil fuels, burning trees, driving cars and from the industry. This excessive carbon dioxide is not absorbed by the environment. This makes our planet warmer and the result is global warming. CLC Methane Gas from animals, agriculture, Arctic Sea beds: Methane is another extremely potent greenhouse gas, ranking right behind CO. When organic matter is broken down by bacteria under oxygen-starved conditions (anaerobic decomposition) as in rice paddies, methane is produced.
The process also takes place in the intestines of herbivorous animals and with the increase in the amount of concentrated livestock production, the levels of methane released into the atmosphere is increasing. Another source of methane is methane celebrate, a compound containing large amounts of methane trapped in the crystal structure of ice. As methane escapes from the Arctic sea beds, the rate of global warming will increase significantly. 12 0 Solar Variation : Variations in solar output have been the cause of past climate changes.
The effect Of changes in solar forcing in recent decades is uncertain but small. Some studies showing a slight cooling effect while others studies suggest a slight warming effect. C] Nitrogen Oxides from Farming : Primary component of the green revolution has been the development of iatrogenic fertilizers that dramatically accelerate the growth and productivity of plants in the field. Plants fix or capture, nitrogen on their own as well but green revolution technologies have become so popular that humans are now adding more nitrogen to the earth than all of the plants in the world combined.
Nitrogen oxides have 300 times more heat-trapping capacity per unit of volume than does carbon dioxide and we release them every time we apply fertilizer to soil. A recent United Nations Food and Agriculture Organization study found that modern farming is contributing more to global arming than all of the transportation sector combined. This is due partly to the fuel burned in modern farming, but more significantly, to the release of methane and nitrogen oxides.
C] Chlorofluorocarbon (CUFF) Gas : Chlorofluorocarbons (CUFF), is used in refrigeration, also powerful greenhouse gas. These gas occur in lower concentrations in the atmosphere, but because they are so much more potent than carbon dioxide, in some cases hundreds of times more potent per unit of volume, they contribute to global warming as well. CLC Deforestation Deforestation increases the severity of global arming as well. Carbon dioxide is released from the human conversion of forests and grasslands into farmland and cities. All living plants store carbon.
When those plants die and decay, carbon dioxide is released back into the atmosphere. As forests and grasslands are cleared for human use, enormous amounts of stored carbon enter the atmosphere. Burning Gasoline for transportation : Our modern car culture and appetite for globally sourced goods is responsible for about 33% of emissions in the U. S. With our population growing at an alarming rate, the demand for more cars and nonuser goods means that we are increasing the use of fossil fuels for transportation and manufacturing.