Water pollution occurs when harmful substances—often chemicals or microorganisms—contaminate a stream, river, lake, ocean, aquifer, or other body of water, degrading water quality and rendering it toxic to humans or the environment.
- 2. Introduction Water pollution is a broad term that describes any kind of contamination of bodies of water such as rivers, lakes or wetlands with substances that can pose threats to human health or the natural environment. Such pollution is a major source of death and disease worldwide, especially in developing nations.
- 3. What is water pollution? Water pollutionis the contamination of water bodies (e.g. lakes, rivers, oceans, aquifers and groundwater), very often by human activities. It occurs when pollutants (particles, chemicals or substances that make water contaminated) are discharged directly or indirectly into water bodies without enough treatment to get rid of harmful compounds.
- 4. Pollutants get into water mainly by human causes or factors. Water pollution is the second most imperative environmental concern along with air pollution. Any change or modification in the physical, chemical and biological properties of water that will have a detrimental consequence on living things is water pollution.
- 5. Odours from rivers, streams, lakes and ocean beaches. Oily and greasy materials floating on surface of water bodies. Unchecked growth of aquatic weeds in water bodies. Bad taste of drinking water. Decrease of aquatic life etc. Noticeable signs of Water Pollution
- 6. Types of water pollution Surface water:- Water resources like huge oceans, lakes, and rivers etc. are called surface waters. Contaminants such as chemicals, nutrients, and heavy metals are carried from farms, factories, and cities into streams and rivers and then to seas and oceans. Our seas are also sometimes spoiled by oil spills. Ground water:- Water stored underground in aquifers is known as groundwater. Groundwater gets polluted when contaminants (pesticides, fertilizers) or waste leached from landfills and septic systems make their way into an aquifer, rendering it unsafe for human use. It is virtually impossible to remove contaminants from groundwater. Groundwater can also spread contamination into streams, lakes, and oceans.
- 7. An Aquifer Aquifers are underground layers of rock that are saturated with water that can be brought to the surface through natural springs or by pumping. ... Groundwater moves more readily through these materials, which allows for faster pumping and other methods of extracting the water
- 9. Sources of Water Pollution Point source: When contamination originates from a single source such as a pipe, such as a discharge pipe attached to a factory. Nonpoint source: When contamination is derived from diffuse sources. This type of pollution is often the cumulative effect of small amounts of contaminants gathered from a large area. These may include agricultural runoff or debris from land into waterways. Transboundary: When contaminated water from one country enters into waters of another country e.g. radioactive waste from reprocessing plant in England is carried by the Gulf Stream to the Norwegian coast; traces of PCBs have even been found in birds and fish in the Arctic. They were carried there through the oceans, thousands of miles from where they originally entered the environment.
- 10. 5 Sources of Water Pollution The main sources of water pollution are natural, agricultural, mining, municipal, industrial and accidental: a) Natural pollution:- • Aerial contaminants entering the water body due to rainfall or melting of ice. • Decaying of plants, animals and organic matter. • Leachates from animal excreta. b) Agricultural pollution:- • Soil and silt washings from land surfaces. • Fertilisers, insecticides, pesticides and weed killers.
- 11. 6 c)Mining pollution:- • Tailings from ore washing • Inert suspended solids • Soluble toxic materials • Acid drainage d)Municipal pollution:- • Sewage obtained from domestic premises, institutions, commercial and industrial buildings. e)Industrial pollution:- • Effluents coming from various industries
- 12. Point sources • Those sources which can be readily identified at a single location. • For instance- industrial, municipal sewage ,treatment plants, combined sewer overflow, raw sewage discharges, etc. • This type of discharge can be controlled. Diffused sources • Those sources whose location cannot be easily identified. • For instance- run off from agriculture lands, forestry, mining, construction, etc. • This cannot be easily controlled. Sources of water pollution :-
- 13. 8 Effects of Water Polluion
- 14. Effects of Water Pollution The adverse effects of water pollution can be studied under the following heads:- i. Physical effects ii. Oxidation effects iii. Toxic chemical effects iv. Chemical nutrient effects v. Micro-organism effects vi. Radionuclide effects
- 15. i. Physical Effects:- • Due to suspended particle solids, cooling water from power stations and oily surface films. • Solids may be inert material wastes or insoluble finely divided organic solids. 1. Inert materials in water slowly accumulate on vegetation foliage, and produce a deposit on river bed. —These may cause reduction in solar energy absorption thereby decreasing rate of photosynthesis causing low oxygen conditions on the river bed. —Suspended materials may also cause turbidity . 2. Finely divided organic solids will be biodegraded and will cause reduction of the dissolved oxygen in water.
- 16. • Cooling water from power stations can cause a rise in water temperature and brings about a thermal pollution. • Variations in temperature will affect the metabolic rate of physiological processes. • At higher temperatures blue green algae and sewage fungus will grow more which will result in plant death. • The oxygen saturation percentage will be reduced and biodegradation will be increased. • Both these factors will cause oxygen deficiency in water.
- 17. • Waste oil, fats and grease can enter from several sources. • These will form a thin film on the water surface which prevents the exchange of oxygen with the atmosphere causing reduction of water oxygen saturation. • Spillage from oil tankers in sea will cause marine pollution and shore contamination. • Oil slicks are responsible for the death of many birds.
- 18. ii. Oxidation Effects:- There are two types of oxidation namely: a) Oxidation by action of bacteria upon organic pollutants. b) Chemical oxidation of other pollutants. • Both type of oxidation involves the use of dissolved oxygen. • It will cause increase in Biological Oxygen Demand (BOD) . • Causes deficiency of oxygen in water. • Bacterial Oxidation- Sulphides • Chemical oxidation- Ferrous salts Sulphate Ferric salts
- 19. iii. Toxic chemical effects:- • Some organic and inorganic chemical substances are toxic to plant, animals and humans. • Chemical toxic substances can be broadly classified as metals and salts, pesticides, acids and alkalies etc. • Pesticide pollutions produce harmful effect over the body. • Acids and alkalies may change the Ph value of water .Changes in ph value may affect physiological processes and actions of toxins.
- 20. iv. Chemical Nutrient Effects:- • Chemical nutrients are required by plants and animals for maintaining their growth and metabolism. • Nitrates and phosphates occur in water in small quantities. • The nutrient levels slowly rise as a result of bio-degradation of dead organic material. This rise in nutrients is called ageing or eutrophication. • Increased concentration of nitrates and phosphates in water produce the overall effects of an increase in the rate of growth of plants and animals. Unicellular green and blue green algae and blanket weed reduce light penetration and restrict reoxygenation of water. • It will cause adverse conditions for river and canal navigation, and for swimming, bathing and fishing. • Nitrates are taken into body by food and drink and excess will cause blood diseases and gastric cancer.
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- 22. v. Micro- organism Effects:- • Wastes that are discharged into water contain pathogenic organisms that are capable of transmitting human diseases. • Bacteria are responsible for cholera, typhoid fever, bacillary dysentery, gastroenteritis. • Virus may cause poliomyelitis, infective hepatitis, and echo and consackil fevers. • Round worm beef and pork tape worms may also cause diseases.
- 23. vi. Radio- Nuclide Effects:- • Solid waste(nuclear) filed in containers is dumped into sea bed. • The corrosive action of sea water my cause leakage of radioactive waste in water and it may pose health hazards. • Radionuclides can enter the human body through dusts and aerosols and can also be absorbed by plants and animals.
- 24. vii. Eutrophication of lakes:- • The condition of excessive growth of plants in a water body is called ‘Eutrophication’. • It is natural process of aging of water body. • It is a result of very slow process of natural sedimentation of microscopic organisms which takes geologic times to complete. • The completion of the process results in the extinction of the water body. • The process is propelled by increasing concentrations of nutrients necessary for biological activity. • Causes decreased D.O( dissolved oxygen), increased B.O.D, and emission of foul gases.
- 25. Classification of Water Pollutant The various types of water pollutants can be broadly classified into four categories. 1.Organic pollutant 2.Inorganic pollutant 3.Radioactive pollutant 4.Suspended solids and sediments
- 26. Organic Pollutant The organic compounds may further be categorised as follows • Natural organic pollutant • Sewage and industrial effluents • Synthetic organic contaminants • Microbiological components
- 27. Natural Organic Pollutant • Natural organic contaminants in water come from the breakdown of naturally occurring organic materials like decay of leaves, plants ,dead animals etc. • Many plants and micro organisms release organic matter in to a water body through their metabolic processes. • Various types of algae and vegetation flourishing in a lake or reservoir can also be a source of objectionable organic compounds in water.
- 28. Sewage and Industrial Effluents • Organic pollutants are also discharged as municipal sewage and industrial effluents (such as food processing units,paper mills,etc .)
- 29. Synthetic Organic Components • These are man made materials which may enter the water bodies along with sewage and other wastes. • Synthetic organic components includes both volatile organic chemicals and synthetic organic chemicals. • Most common organic pollutant in VOC are industrial solvents , such as carbon tetrachloride(used as fire extinguisher and cleaning agent). • Most common organic pollutant in SOC are pesticides and herbicides. • Presently , the most controversial organic pollutant are polychlorinated biphenyls and dioxin, which are very toxic and known to cause caner even at very low concentration.
- 30. Micro-biological Pollutants • Many different micro organisms such protozoa ,viruses , bacteria are found in polluted water. • Most of these do not pose a health hazard to humans. • The organisms that can cause sickness In human are called pathogenic organisms.
- 31. Inorganic Pollutant • Apart from the organic matter discharged in the water body through sewage and industrial wastes high concentration of heavy metals and other inorganic pollutants contaminates the water. • The accumulation of heavy metals may have adverse effect on aquatic flora and fauna and may constitute a public health problem where contaminated organisms are used for food. • Algal growth due to nitrogen and phosphorous compounds can be observed . Metals in high concentration can be toxic to biota.
- 32. Radioactive Pollutant • Radioactive material orginates from the following: • Mining and processing of ores. • Use in research ,agriculture ,medical , and industrial activities such as I131 ,P32 ,CO60 , Ca45 ,S35 , ETC. • Radioactive discharge from nuclear power plants and nuclear reactors. • Uses and testing of nuclear weapons. • These isotopes are toxic to lifeforms ,they accumulate in the bones and can cause serious disorders.
- 33. 29 Suspended Solids And Sediments • Comprises of silt ,sand , and minerals eroded from land. • Appears in the water through surface runoff during rainy season and through municipal sewers. • This can lead to the siltation , reduces storage capacities of reservoirs. • Deposition of solids in the quiescent stretches of the stream and ocean bottom can affect normal aquatic life and affect the diversity of aquatic ecosystem.
- 35. Common Water-Borne Diseases Water-borne diseases are caused by pathogenic organisms carried by water containing faecal or sewage contamination. a) Bacterial Diseases 1.Typhoid fever:- • Typhoid fever is the most important endemic and epidemic water borne disease of regions where supplies are drawn from surface sources contaminated by human faeces or urine. • This is caused by the bacterium salmonella typhi.
- 36. 2.Paratyphoid fever:- • Mostly due to ingestion of contaminated food, specially milk, dried or frozen eggs and other diary products. • This is caused by bacterium Salmonella paratphi A, B or C. • Number and infectivity of organisms released to environment are generally smaller than the typhoid fever. 3.Cholera:- • This is caused by the bacterium vibrio cholerae. • Usually the infection is contracted by ingestion of water contaminated by infected human faecal material. • Sometimes it may be contracted by contaminated food or personal contact. • Cholera is much more violent in its onset and often more fulminating in its clinical course.
- 37. 4.Bacillary dysentery:- • This is caused by bacteria of genus shigella, Sh. Dysentrial, Sh. Flexneri, Sh. Boydii and Sh. Sonnei. • This disease is mostly contracted due to ingestion of food contaminated by flies or by unhygienic food handlers. • It may sometimes be contracted by consuming water contaminated by human faeces. b) Protozoal Diseases:- • The 2 important diseases that come under this category are: • Amoebiasis and amoebic dysentery. • These are caused by the protozoon entamoeba histolytica. • They live in the human large intestine forming cyst which are excreted in the bowel discharges of infected persons and which will live for long periods in water. • Infection takes place due to ingestion of these cysts which are carried by water or flies or even human fingers.
- 38. c) Virus Diseases:- • The recognized viruses that are of serious concern are the following members of the enteric virus group: polio viruses, coxsakie viruses , ECHO viruses, the viruses of infectious hepatitis, the adenoviruses and the reoviruses. • The poliovirus persists in the intestines of infected persons for a short time after infection which probably takes place from contaminated fingers directly or on food. • Poliomyelitis is common where sanitation and food hygiene are poor. d) Helminthic (worm) disease:- • Worm infections are sporadic and occur only under grossly insanitary conditions or through gross mismanagement of sewage disposal system. • The common diseases that are spread are schistosomiasis and swimmer’s itch. • The causes of schistosomiasis is a group of trematode worms that inhibit the viens of bladder or large intestines and discharge eggs into the urine.
- 39. Related legislation Water act 1976 The act was enacted in 1974 with the objective to provide for the prevention and control of water pollution and for the maintaining or restoring of wholesomeness of water in the country. It provides for the establishment of central state and joint pollution control boards for the prevention and control of water pollution and defines their powers and responsibilities.
- 40. The Water(Prevention and Control of Pollution) Cess Act 1977 The Water(Prevention and Control of Pollution) Cess Act was enacted in 1977, to provide for the levy and collection of cess on water consumed by persons operating and carrying on certain types of industrial activities. This cess was meant to collect with a view of argument the resources of the Central Board and the State Boards for the prevention and control of water pollution.
- 41. Environment (Protection) Act 1986 Environment (Protection) Act 1986 provides for the protection and improvement of environment and the matters associated with it.
- 42. Way Forward Need for action to address human and environmental harm. Information campaigns to raise awareness. Prevention efforts to stem some of the worst problems. Investments to treat pollution once it has occurred , with more modern technologies like reverse-osmosis offering new pathways.
- 43. Various Causes of Water Pollution 1.Industrial Waste Industries produce a tremendous amount of waste, which contains toxic chemicals and pollutants, causing air pollution and damage to our environment and us. They contain harmful chemicals, like lead, mercury, sulfur, nitrates etc. Many industries, not having a proper waste management system, drain the waste in the freshwater, which goes into canals, rivers, and later into the sea. The toxic chemicals may change the color of water, increase the number of minerals, called eutrophication, change the temperature of the water, and pose a severe hazard to water organisms.
- 44. 2. Sewage and Wastewater The sewage and wastewater that is produced in each household are treated chemically and released into the sea along with fresh water. The sewage water carries pathogens, a typical water pollutant, other harmful bacterias, and chemicals that can cause serious health problems and thereby diseases. Microorganisms in water are known to cause some of the very deadly diseases and become the breeding grounds for creatures that act as carriers. These carriers inflict these diseases onto an individual via various forms of contact. A typical example would be Malaria.
- 45. 3. Mining Activities Mining is the process of crushing the rock and extracting coal and other minerals from the underground. These elements, when extracted in the raw form, contain harmful chemicals and can increase the number of toxic elements when mixed up with water, which may result in health problems. Mining activities emit a large amount of metal waste and sulfides from the rocks, which is harmful to the water.
- 46. 4. Marine Dumping The garbage produced by households in the form of paper, plastic, food, aluminum, rubber, glass, is collected and dumped into the sea in some countries. These items take 2 weeks to 200 years to decompose. When such things enter the sea, they not only cause water pollution but also harm animals in the sea.
- 47. 5. Accidental Oil Leakage Oil spill poses a huge threat to marine life when a large amount of oil spills into the sea and does not dissolve in water. It causes problems for local marine wildlife, including fish, birds, and sea otters. A ship carrying a large quantity of oil may spill oil if met with an accident. Such an oil spill can cause varying damage to species in the ocean, depending on the amount of oil spill, the toxicity of pollutants, and the size of the ocean.
- 48. 6. The burning of fossil fuels Fossil fuels like coal and oil, when burnt, produce a substantial amount of ash in the atmosphere. The particles which contain toxic chemicals when mixed with water vapor result in acid rain. Also, carbon dioxide is released from the burning of fossil fuels, which results in global warming.
- 49. 7. Chemical fertilizers and pesticides Chemical fertilizers and pesticides are used by farmers to protect crops from insects and bacterias. They are useful for the plant’s growth. However, when these chemicals are mixed up with water, they produce harmful pollutants for plants and animals. lso, when it rains, the chemicals mix up with rainwater and flow down into rivers and canals, which pose serious damages for aquatic animals.
- 50. 8. Leakage From Sewer Lines A small leakage from the sewer lines can contaminate the underground water and make it unfit for the people to drink. Also, when not repaired on time, the leaking water can come on to the surface and become a breeding ground for insects and mosquitoes.
- 51. 9. Global Warming An increase in the earth’s temperature results in global warming due to the greenhouse effect. It increases the water temperature and results in the death of aquatic animals and marine species, which later results in water pollution.
- 52. 10. Radioactive Waste Nuclear energy is produced using nuclear fission or fusion. The element that is used in the production of nuclear energy is Uranium, which is a highly toxic chemical. The nuclear waste that is produced by radioactive material needs to be disposed of to prevent any nuclear accident. Nuclear waste can have serious environmental hazards if not disposed of properly. Few major accidents have already taken place in Russia and Japan.
- 53. 11. Urban Development As the population has grown exponentially, so has the demand for housing, food, and cloth. As more cities and towns are developed, they have resulted in increasing use of fertilizers to produce more food soil erosion due to deforestation, rise in construction activities inadequate sewer collection and treatment landfills as more garbage is produced increase in chemicals from industries to produce more materials.
- 54. 12. Leakage From the Landfills Landfills are nothing but a massive pile of garbage that produces the awful smell and can be seen across the city. When it rains, the landfills may leak, and the leaking landfills can pollute the underground water with a large variety of contaminants.
- 55. 13. Animal Waste The waste produced by animals washed away into the rivers when it rains. It then gets mixed up with other harmful chemicals and causes various water-borne diseases like cholera, diarrhea, dysentery, jaundice, and typhoid.
- 56. 14. Underground Storage Leakage Transportation of coal and other petroleum products through underground pipes is well known. Accidental leakage may happen anytime and may cause damage to the environment and result in soil erosion.
- 57. 15. Eutrophication (Gr. eutrophos= well-nourished) Although phosphorus and nitrogen are necessary for plant growth but in excess levels they over stimulate the growth of aquatic plants and algae. The increased level of nutrients in water bodies is known as Eutrophication. It results in the bloom of algae in the water. When the algae die or are eaten, neuro- and hepatotoxins are released which can kill animals and may pose a threat to humans e.g. shellfish poisoning. Decomposition of blooms also depletes the amount of oxygen in the water that negatively affects fish and other aquatic animal populations.
- 58. 16. Acid Rain Acid rain is essentially water pollution caused by air pollution. Atmospheric Sulfur dioxide and nitrogen dioxide emitted from natural and human- made sources like volcanic activity and burning fossil fuels interact with atmospheric chemicals, including hydrogen and oxygen, to form sulfuric and nitric acids in the air. These acids fall down to earth through precipitation in the form of rain or snow. Once acid rain reaches the ground, it flows into waterways that carry its acidic compounds into water bodies. When the acidic particles released in the atmosphere by air pollution mix with water vapor, it results in acid rain.
- 59. 17.Biomagnification It is also known as bioamplification or biological magnification. It is increase in concentration of a substance, such as a toxic chemical, in the tissues of tolerant organisms at successively higher levels in a food chain. Persistent organic pollutants or POPs like DDT (dichlorodiphenyltrichloroethane), hexachlorobenzene (HCB), PCBs (polychlorinated biphenyls), monomethylmercury etc. show biomagnification. E.g. DDT when enters an aquatic ecosystem, it keeps on moving from water to different living components of the aquatic system and its concentration continuously increases in successive trophic levels in a food chain
- 60. Biomagnification in food chain
- 62. EFFECT OF WATER POLLUTION EFFECT ON AQUATOC ECOSYSTEM:- 1. Polluted water reduces dissolved oxygen content and thereby eliminates the sensitive organisms like planktons, molluscs and fish. 2. Pesticides directly sliminate sensitive aquatic organisms 3. Algal blooms 4. Reduction in the area of water bodies as in the case of Dal Lake area has been reduced from 15 km in 982 to 12 km only at present. EFFECTS OF THERMAL POLLUTION:- 1. Deoxygenation of water bodies. 2. Trouts eggs fail to hatch and some fishes fail to spawn. 3. Decreases photosynthesis rate in water plants. 4. Radioactive pollution.
- 63. EFFECTS ON HUMAN BEINGS 1. Disease causing microorganisms like Viruses, Bacteria, Parasitic, Protozoa are known as pathogens and these pathogenes are spreading disease directly among humans. It is a source of water borne disease like Diarrhoea, Jaundice, Cholera, Typhoid Amoebiasis etc. 2. Mercury compounds in water waste are converted by becteria actioninto extremely toxic compound methyl mercury. Which can cause numbness of limba, lips and tounge , deafness, blurring of vision and mental problems. Minamata disease(1952) is a poisoning disease that effect mainly the central nervous. 3. Water contaminated with Cadmium causes itai itai disease (a Painful disease of bone and joints) and cancer of lungas and liver. 4. Excess of nitrates in drinking water dangerous to human health which reacts with haemoglobin of the blood and forms methaemoglobin and impairs oxygen Transport. This condition is called methhaemoglobinaemia or blue baby syndrome.
- 64. EFFECTS ON HUMAN BEINGS 5. Excess of fluoride in drinking water causes neuromuscular disorders, gastrointestinal problems teeth deformity, hardening of bones and stiff and painful joints(skeletal flourisis) 6. Drinking of Arsenic polluted water cause black foot disease. It also causes Diarrhoea, Peripheral neuritis, hyperkerartosis and also lung and skin cancer.
- 65. CONTROL MEASURES OF WATER POLLUTION Hot water should be cooled before release from the power plants. Cleaning in tank, streams and rivers which supply drinking water should be prohibited. Judicious use of agrochemicals like pesticides which will reduce their runoff and leaching. Domestic excessive use of fertilzers and pesticides should be avoided. Organic farming and Efficient useof animal residues as fertilizer. Use nitrogen fixing plants to supplement the use of fertilizers. Planting trees would reduce pollution by sediments and will also prevent soil erosion. For the control of industrial wastes and toxic compounds should be purified before draining into rivers ,Lakes and Seas. Waste Water should be properly treated by primary and secondary methods. Oil spills in water should be cleaned by suitable methods. Water hyacinth (an aquatic weed) can purify water by taking toxic chemicals and heavy metals.