unit ONE Ecology of Polluted Water.pptx

ECOLOGY, EUTROPHICATION WASTE MANAGEMENT

1. Ecology of Polluted Water DR. AKSHAYA GUPTE

2. Aquatic Ecosystem Water is an environment. Many discharges which affect the quality of water as a resource also induce associated and proportional ecological changes in the aquatic communities. Water movements are also ecologically important. 1) Lentic waters: Standing water bodies (Ponds, lakes etc.) 2) Lotic waters: Flowing water (River, Stream etc.)

3. Lotic systems (Flowing) are tend to be more sensitive to changes e.g addition of effluents-response sharply. Lentic systems (Standing) are less sensitive and generally respond more slowly but eventual change may be huge and long lasting. Depth profile, light penetration, thermal stratification are ecological parameters of lentic water while current velocity, wind direction, related nature of substratum are ecological parameters of lotic water systems.

4. Ecological Classification of water Pollution Three major groups: Physical, Chemical and Biotic Physical pollution: 1. Changes in physical factors 2. Changes in physical nature of substratum Suspended Solids, Turbidity and Color: Affect light penetration therefore affect primary producers. e.g.1. Dumping of China-clay wastes: causes turbidity decrease algal growth 2. Dumpling of silt- affect fishes 3. Dumping of inert solids: like coal-dust, gravels washings, metal mining wastes results in reduction of all spp. growth

5. Dumping of different organic load: Responsible to establish silt community, Mainly: Chironomus riparius (Blood worms), Asellus aquaticus ( Waterlouse ) : They are freshwater crustacean, supply abundant food to those fishes who can tolerate such environment. Colour: Presence of dyes and waste from paper, tannery, textile industries are responsible for colour in aquatic environment. Minute amount of dye particles presence in aquatic system make it aesthetically unacceptable.

6. Surface active agents: Presence of natural soaps, synthetic detergents are responsible to change the surface tension of the water and thereby affect different biological possesses: 1 . Egg-laying activities of insects 2. Growth of neustron (Orgs. associated with air-water interface)

7. 3. Retarding self-purification of water from organic pollution 4. If detergents concentration increases > 5ppm, Epithelial cells of the gills of carp are destroyed. Temperature: Elevated temperature interface with the seasonal life cycles of a aquatic insects. Limited food and high temp. can reduce the growth. The death rate of fishes increases with increase in temp. Phenol concentration may be increased due to enhanced detoxification at high temperature.

8. Radioactivity: 137Cs, 85 Sr and 32P are probably the most important in aquatic system. Many algal spp. capable of concentrating these radioactive compound .

9. Chemical Pollution Salinity: Salts of Na, Ca, K and Mg are present in such proportions that their individual toxicities are mutually counteracted or antagonized. Continuous discharges from salt and coal mines and oil wells which create fairly stable saline conditions. The brine shrimp, Artemia salina , the salt fly and certain rotifiers and diatoms have been found in such water bodies.

10. pH: Within the range 5-9, pH probably has no significant direct effect on most species. E.g. Snails are usually found in waters with pH above 7. pH can affect the toxicity level of certain chemicals. Ammonia e.g. 10 times more toxic at pH 8 than at 7, whereas a nickelo -cyanide complex was found to be 500 times more toxic to fish at pH 7 than at pH 8. More amount of presence of elemental sulfur derivatives and sulfide derivatives undergo oxidation and as a result form sulfuric acid which responsible for acidic pH of the water body. This can further cause gastrointestinal problem.

11. Toxicity: The effect of toxic pollution on aquatic communities are the reduction in both the no of species and in the total no of individuals. Different species exhibit different degree of tolerance to different toxicants. E.g Spp. of leech show high degree of tolerance to DDT. This kind of observation is noted as they detoxify the DDT to DDE by dehydrochlorination process.

12. Toxic Effect may be of different types: 1. lethal 2. Sub-lethal 3. Acute 4. Chronic and 5. Accumulative. The toxicants in the aquatic environment besides affecting aquatic communities, pollute the water as a resource for public supply. E.g. In Japan, due to discharged of effluent containing mercury from a venyl chloride plant caused poisoning after eating fishes in Minamata Bay.

13. Deoxygenation : Dissolved O2 is a major factor determining the distribution of invertebrates and fish in freshwaters. Most species are limited by low O2 content but invertebrates e.g. Chirononus riparius are adversely affected by high O 2 levels and have been found to survive at low O 2 levels. However, different species select their suitable sites as per availability of the oxygen.

14. BOD (Biochemical Oxygen Demand): Biochemical oxygen demand is the amount of dissolved oxygen needed by aerobic biological organisms to break down organic material present in a given water sample at certain temperature over a specific time period CBOD and NBOD COD (Chemical Oxygen Demand): It is an indicative measure of the amount of oxygen that can be consumed by reactions (K 2 Cr 2 O 7 ) in a measured solution using ferroin as an indicator.

15. Total organic carbon (TOC) is the amount of carbon found in an organic compound and is often used as a non-specific indicator of water quality. By subtracting the inorganic carbon from the total carbon yields  TOC . Measurement using TOC Analyzer.

16. WATER POLLUTION & NOISE POLLUTION

17. What is water pollution? Water pollution is the contamination of water bodies (e.g. lakes, rivers, oceans and groundwater), very often by human activities. 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. It occurs when pollutants are discharged directly or indirectly into water bodies without enough treatment to get rid of harmful compounds. Pollutants get into water mainly by human causes or factors. Water pollution is the second most imperative environmental concern along with air pollution.

18. Sources of Water Pollution There are various classifications of water pollution. The two chief sources of water pollution can be seen as Point source Non-Point source

19. Point source Those sources which discharge water pollutants directly into the water are known as point sources of water pollution. Oil wells situated near water bodies, factories, power plants, underground coal mines, etc. are point sources of water pollution. Non-Point source Those sources which do not have any specific location for discharging pollutants, in the water body are known as non-point sources of water pollution. Run-offs from agricultural fields, lawns, gardens, construction sites, roads and streets are some non-point sources of water pollution.

20. 1. Nutrients Pollution Some wastewater, fertilizers and sewage contain high levels of nutrients . If they end up in water bodies, they encourage algae and weed growth in the water . This will make the water undrinkable, and even clog filters . Too much algae will also use up all the oxygen in the water, and other water organisms in the water will die out of oxygen starvation. What are the types of water pollution

21. 2. Surface water pollution Surface water includes natural water found on the earth's surface, like rivers, lakes, lagoons and oceans . Hazardous substances coming into contact with this surface water, dissolving or mixing physically with the water can be called surface water pollution.

22. 3. Oxygen Depleting Water bodies have micro-organisms including aerobic and anaerobic organisms. When to much biodegradable matter end up in water, it encourages more microorganism growth, and they use up more oxygen in the water. If oxygen is depleted, aerobic organisms die, and anaerobic organism grow more to produce harmful toxins such as ammonia and sulfides.

23. 4 . Ground water pollution When humans apply pesticides and chemicals to soils, they are washed deep into the ground by rain water . This gets to underground water, causing pollution underground . This means when we dig wells and bore holes to get water from underground, it needs to be checked for water pollution.

24. 5. Suspended Matter Some pollutants (substances, particles and chemicals) do not easily dissolve in water. This kind of material is called particulate matter. Some suspended pollutants later settle under the water body. This can harm and even kill aquatic life that live at the floor of water bodies.

25. 6. Chemical Water Pollution Many industries and farmers work with chemicals that end up in water. These include chemicals that are used to control weeds, insects and pests. Metals and solvents from industries can pollute water bodies. These are poisonous to many forms of aquatic life and may slow their development, make them infertile and kill them.

26. 7 . Oil Spillage Oil spills usually have only a localized effect on wildlife but can spread for miles . The oil can cause the death to many fish and get stuck to the feathers of seabirds causing them to lose their ability to fly.

27. Water pollutants River, lake and sea water may be polluted in many ways: Domestic sewage discharged into rivers from areas located on its banks. Industrial wastes effluents from urban areas containing high concentration of oil, heavy metals and detergents. Chemical fertilizers, pesticides, insecticides, herbicides and plant remains. Radioactive waste from nuclear reactor. Excretory wastes of humans and animals in water bodies.

28. Surface Water Quality & Pollution Issues Topics Covered Water quality, pollution sources, types of pollution, water quality parameters, water quality standards. Keywords: Water quality, pollution sources, types of pollution, parameters, standards . 2

29. Watershed Management & Water Quality Watershed management – Water quantity & quality – Importance Assessment & monitoring of water quality – livelihoods of watershed dwellers WQ – examination to determine organisms, minerals & organic compounds in water Depending on use of water Physico-chemical, chemical & microbiological analyses 3 of water Common issues of Surface and Groundwater Pathogenic (Bacteriological) Pollution; Salinity Toxicity (micro-pollutants and other industrial pollutants)

30. Water Quality Standards Water quality indicates the physical, chemical and biological characteristics of water. It is a measure of the condition of water relative to the requirements of one or more biotic species and or to any human need or purpose. It is most frequently used by reference to a set 4 of standards against which compliance can be assessed. The most common standards used to assess water quality relate to health of ecosystems, safety of human contact and drinking water.

31. Water Quality Categories Human consumption- Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contaminants. Presence of these contaminants does not necessarily indicate that water poses a health risk. Industrial use Dissolved minerals may affect suitability of water for a range of industrial and domestic purposes. 5 presence of ions of calcium and magnesium which interfere with the cleaning action of soap, and can form hard sulfate and soft carbonate deposits in water heaters or boilers. Hard water may be softened to remove these ions. Softening may sacrifice nutrition for cleaning effectiveness.

32. Water Quality Categories In the environment. Toxic substances and high populations of certain microorganisms can present a health hazard for non-drinking purposes such as irrigation, swimming, fishing, rafting, boating, and industrial uses. These conditions may also affect wildlife, which use the water for drinking or as a habitat. 6 Irrigation purpose : Crop production – irrigation water quality requirements Agriculture- single largest user of freshwater - a major cause of degradation of surface and groundwater resources through erosion and chemical runoff

33. Water Pollution Sources Water pollution is the contamination of water bodies e.g. lakes, rivers, oceans and groundwater. Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds. Water pollution affects plants and organisms living in these bodies of water. The effect is damaging to individual species and populations and natural biological communities. 7

34. Water Pollution – Source Types Water Pollution – Point or non-point sources Water pollution- point sources: contaminants that enter a waterway from a single, identifiable source, such as a pipe or ditch. Traced to a specific source Leaking chemical tank, effluents coming from a waste treatment or industrial plant, or a manure spill from a hog confinement lagoon Examples – discharges from a sewage treatment plant; a factory; a city storm drain; municipal storm sewer systems; industrial storm water, such as from construction sites 8

35. Water Pollution - Source Types 9 Water pollution- non point sources Non–point source pollution (NPS)- contamination that does not originate from a single discrete source. NPS pollution is the cumulative effect of small amounts of contaminants gathered from a large area. Pollutants will come from wide spread area They can’t be tracked to a single point or source Examples: Soil erosion, chemical runoff, animal waste pollution – leaching out of fertilizers/ nutrients agricultural lands. – Nutrient runoff in storm water- agricultural field/ forest. – Contaminated storm water washed off of parking lots, roads and highways, called urban runoff,

36. http://pottyon.com/ Water Pollution – Specific Sources Septic systems - Use a large tank buried in the ground to contain and break down household sewage; Fats, oils, and grease as well as large waste particles, are stored and later pumped out of the holding tank; source of concern for groundwater pollution & surface water pollution Lagoons: shallow holding pits into which wastes are pumped and treated; Water Quality Problems: Poorly constructed lagoons (leakage); lagoons built on high water table; Nitrates: most often found contaminant Waste Disposal: Underground or above ground disposal practices of domestic, municipal, or industrial liquid waste 10 www.uncwil.edu

37. Water Pollution – Specific Sources Industrial liquid waste – treated/ untreated Solid waste - Land disposal of municipal and industrial solid waste – leaching Storage and Transport of Commercial Materials – storage tanks & spills Mining operations: Mines, Oil & gas- Acid mine drainage, Leaching of toxic metals, Wastewater generated Agricultural operations: Fertilizers; Pesticides Saline water intrusion 11 www.bio.vu.nl

38. Water Pollution- Causes Wide spectrum of chemicals , pathogens , and physical or sensory changes such as elevated temperature and discoloration. Natural occurring – eg. Salts, fluoride, arsenic, Ca, Mg, Na etc. Artificial – disposed by humans from various sources Water's physical chemistry includes acidity (change in pH ), electrical conductivity , temperature, and eutrophication 12

39. Water Pollution Types Water pollution- organic pollutants Detergents; Disinfection by-products Food processing waste, fats and grease Insecticides & herbicides, organohalides and other chemical compounds Petroleum hydrocarbons, including fuels (gasoline, diesel fuel, jet fuels, and fuel oil) & lubricants (motor oil), & fuel combustion byproducts Tree and bush debris from logging operations Volatile organic compounds (VOCs), such as industrial solvents. Chlorinated solvents, dense non-aqueous phase liquids (DNAPLs), Polychlorinated biphenyl (PCBs) –Trichloroethylene, Perchlorate . Various chemical compounds found in personal hygiene & cosmetic products 13

40. Water Pollution Types Water pollution- inorganic pollutants Acidity caused by industrial discharges (sulfur dioxide from power plants) Ammonia from food processing waste Chemical waste as industrial by-products Fertilizers containing nutrients- nitrates and phosphates- which are found in storm water runoff from agriculture, as well as commercial and residential use Heavy metals from motor vehicles (via urban storm water runoff) and acid mine drainage Silt (sediment) in runoff from construction sites, logging, slash and burn practices or land clearing sites 14

41. Pollution- macroscopic/ Micro pollutants Macroscopic - Large visible items polluting the water— may be termed "floatables" in an urban stormwater context, or marine debris when found on the open seas like Trash or garbage (e.g. paper, plastic, or food waste) discarded by people on the ground dumping of rubbish, that are washed by rainfall into storm drains and eventually discharged into surface waters Nurdles, small ubiquitous waterborne plastic pellets – Shipwrecks, large derelict ships Microscopic pollutants – micro organisms, dissolved/ dispersed pollutants 15

42. Water pollution- thermal pollution The rise or fall in the temperature of a natural body of water caused by human influence. Thermal pollution results in a change in the physical properties of water. A common cause of thermal pollution is the use of water as a coolant by power plants and industrial manufacturers. Elevated water temperatures decreases oxygen levels (which can kill fish) and affects ecosystem Urban runoff may elevate temperature in surface waters. Thermal pollution can also be caused by the release of very cold water from the base of reservoirs into warmer rivers. 16

43. Water Quality - Parameters Following is a list of indicators often measured: Alkalinity; Color of water; pH; Taste and odor Dissolved metals and salts (sodium, chloride, potassium, calcium, manganese, magnesium) Microorganisms such as fecal coliform bacteria , Cryptosporidium, and Giardia lamblia Dissolved metals & metalloids (lead, mercury, arsenic, etc.) Dissolved organics: colored dissolved organic matter (CDOM), dissolved organic carbon (DOC), Heavy metals Pharmaceuticals byproducts Parameters depend on type of use – eg. Drinking, Industrial use, Irrigation etc. 17

44. Water quality-environmental indicators Chemical assessment: Dissolved oxygen (DO); Nitrate-N; Orthophosphates; Chemical oxygen demand (COD); Biochemical oxygen demand (BOD); Pesticides; Metals Physical assessment : pH; Temperature; Total suspended solids (TSS); Turbidity; Total dissolved solids (TDS) Biological assessment : Biological monitoring metrics have been developed in many places, and one widely used measure is the presence and abundance of members of the insect orders Mayfly, Stonefly and Caddisfly. 18

45. Important Water Quality Parameters Important physicochemical parameters to be tested for ascertaining water quality are: pH; Colour, Taste and odour, turbidity, TDS, total hardness, chlorides, sulphates, fluorides, nitrates, calcium, heavy metals, dissolved oxygen, pesticides, detergents & radio-nuclides pH – neutral (pH -7); acidic (pH<7); basic (pH>7); drinking water (6.5-8) Electrical conductivity – water ability to conduct electrical current – depends on concentration of dissolved, associated substances – to find TDS – unit micro siemens cm 19 19

46. Important Water Quality Parameters.. Odour, Colour & Taste – Odour – classified as: very weak, weak, clear, strong or very strong Colour – tested using colorimter tubes – expressed in Hazen standard unit Taste – purest form tasteless Turbidity – caused by presence of suspended matter – ranges in size from colloidal to coarse dispersions – measured by Nephelo/ turbidity meter & expressed in NTU (Nephelometric turbidity unit) – indicator necessity of treatment Dissolved oxygen – indicates amount of oxygen gas dissolved in water – solubility of atmospheric oxygen in fresh water ranges from 14.6 mg/l at o C to about 7 mg/l at 35 o C under 1 atmospheric pressure – measured using DO meter. 20

47. Important Water Quality Parameters.. 21 BOD (Biochemical Oxygen Demand) – amount of dissolved O 2 demanded by bacteria during stabilization of the decomposable organic matter under aerobic conditions – BOD expressed in mgm of O 2 consumed/ lit of sample during 5 days of incubation at 20 °C & is often used as a robust surrogate of degree of organic pollution of water – prestine river BOD<1mg/l. Nitrate- water soluble molecule made up of nitrogen & oxygen – natural constituent of plants – In natural form water contains less than 1mg of nitrate- nitrogen per litre – higher levels – contamination; common sources: fertilizers, animal wastes etc. – max. permissible 10ppm Chlorides – from dissolved salt deposits, discharge of effluents etc. – max. limit: 250 ppm.

48. Important Water Quality Parameters.. Fluorides - fluorine containing compounds - fluorides - found naturally in low concentration in drinking water and foods -Fresh water -between 0.01–0.3 ppm, ocean contains between 1.2-1.5 ppm; max. permissible 1ppm. – more fluorine – diseases like skeletal fluorosis Hardness – represents total concentration of Ca & Mg ions – ppm (weight/ volume) -Hard water is generally not harmful to one's health, but can pose serious problems in industrial settings. Iron - naturally occurring – not hazardous – recommended limit – 0.3mg/l. 22

49. Important Water Quality Parameters.. Heavy Metals: Arsenic, Cadmium, Chromium, Copper, Iron, Manganese, Mercury, Nickel, Silver, Zinc etc. – Present in as minerals in soils; also artificially from man made things – some of these – major contaminations – determined by AAS (atomic absorption sepctrophotometer), polarography or colorimetry. – Arsenic – WHO guideline < 0.05 mg/l Pesticides: - harmful health effects such as cancer; eg. DDT, BHC, parathon, endosulphan etc. 23 Detergents, phenol, radio-nuclides etc . - WHO guideline < 0.5 mg/l Halogenated chloro-organic compounds – due to higher chlorination for disinfection Microbes – indicator potential water-borne diseases – bacteria, viruses & pathogenic protozoa; eg. Coliform bacteria.

50. Common Water Related problems Observed Problems Causes Water turns black, smell Waste water Acidic taste Low pH Alkaline taste High pH Boiled Rice hard and yellow High Alkalinity White deposits on boiling Hardness 24

51. Observed Problems Causes Common Water Related problems Iron taste, change in colour after exposure to atmosphere, change in Presence of colour of cloths, utensils Oily appea- rance on top of water body Iron compounds Soap not lathering hardness Brownish black streaks on teeth Fluoride Growth of Algae Nitrate, phosphate Fish kills Low pH less DO 25 Salty taste chloride

52. WQ – Tolerance & Classification As per ISI-IS: 2296-1982, the tolerance limits of parameters are specified as per classified use of water (Table below) depending on various uses of water. http://cpcb.nic.in ; http://wrmin.nic.in 26

53. Tolerance Limits for Inland Surface Water – Class A http://cpcb.nic.in ; http://wrmin.nic.in 27

54. Tolerance Limits for Inland Surface Water – Class B http://cpcb.nic.in ; http://wrmin.nic.in 28

55. Tolerance Limits for Inland Surface Water – Class C http://cpcb.nic.in ; http://wrmin.nic.in 29

56. Tolerance Limits for Inland Surface Water – Class D http://cpcb.nic.in ; http://wrmin.nic.in 30

57. Tolerance Limits for Inland Surface Water – Class E 3 1 31

58. Self Evaluation - Questions!. Discuss the various water quality issues in watershed management. Describe various water quality categories. What are the different pollution source types?. Describe various water pollution causes. Illustrate water pollution by thermal sources Describe various water quality parameters. 38

59. Assignment- Questions?. Describe the water quality standards. Discuss various water pollution sources Describe various specific sources of water pollution. Illustrate various water pollution types Describe various water quality indicators What are the various common water related problems?. 39 Prof. T I Eldho, Department of Civil Engineering, IIT Bombay

60. Unsolved Problem!. Critically study the possible surface water pollution problems in your watershed area. Identify the water sources & possible causes of pollution. What are the roles of agriculture, land use, and industries/ other uses in the pollution problems. Prepare a plan to reduce the possible pollution problems 40

61. Effects of Water Pollution The effects of water pollution are varied and depend on what chemicals are dumped and in which locations. Many water bodies near urban areas are highly polluted. This is the result of both garbage dumped by individuals and dangerous chemicals legally or illegally dumped by manufacturing industries, health centers, schools and market places.

62. Health Effects Consumption of polluted water is a major cause of ill health in India. Polluted water causes some of the deadly diseases like cholera, dysentery, diarrhea, tuberculosis, jaundice, etc. About 80 per cent of stomach diseases in India are caused by polluted water.

63. Effect of Nutrients- Eutrophication Water supports aquatic life because of the presence of nutrients in it. Excess fertilizers from agricultural fields may mix with surface water and may get drained into water bodies (surface runoff). The enrichment of water with nutrients such as nitrates and phosphates that triggers the growth of green algae is called eutrophication. This fast growth of algae followed by decomposition depletes the water body of its dissolved oxygen. As a result aquatic animals die of oxygen shortage.

64. Sewage and/or fertilizer run off from fields ↓ Enriched nutrient content in lakes (Eutrophication) ↓ Algae multiply to produce an ‘algal bloom’ ↓ Algae use up oxygen and begin to die ↓ Decomposers (bacteria) multiply and use more oxygen ↓ Organisms (such as fish) die due to lack of oxygen

65. Effect of Toxic Pollutants Toxic pollutants mainly consist of heavy metals, pesticides and other individual xenobiotic pollutants. Some metals e.g., Mn, Zn and Cu present in trace quantity are important for life as they help and regulate many physiological functions of the body. Some metals, however, cause severe toxicological effects on human health and the aquatic ecosystem.

66. Biomagnification Non-biodegradable pesticides, such as DDT are widely used for crop protection. Once they enter the food chain, their concentration keeps on increasing with each trophic level (steps of a food chain). As a result, accumulation of these compounds takes place in the body of top consumers over a period of time. Entry of harmful non-biodegradable chemicals in small concentrations and their accumulation in greater concentrations in the various levels of food chain is called biomagnification.

67. Water → Algae → Fish → Pelican bird (top consumer) DDT used in small quantities to kill mosquitoes can enter the food chain and may get concentrated in large concentration due to its non-biodegradable nature in the body of birds (top) consumer. This causes adverse effects, such as weak egg shells, resulting in decreased population. 0.2 ppm 77 ppm 500-600 ppm 1700 ppm

68. Control of water pollution Recycling and Reuse of water Treating industrial effluents before discharging into rivers, separate channels for river and sewage water Avoid contamination of rivers, lakes and ponds by washing clothes, bathing. etc. Not throwing waste, food materials, paper, biodegradable vegetables and plastic into open drains.

69. Qualified and experienced people must be consulted from time to time for effective control of water pollution. Public awareness must be initiated regarding adverse effects of water pollution using the media. Laws, standards and practices should be established to prevent water pollution and these laws should be modified from time to time based on current requirements and technological advancements.

70. ….. EUTROPHICATION

71. When lakes, streams and estuaries are over fertilized, excessive production of aquatic organic matter can become a water quality problem and as a result the Eutrophication process can be enhanced!

72. However , humans in their everyday activities can exacerbate the process: Point sources (can locate the cause) Sewage treatment plant discharges Storm sewer discharges Industrial discharges Non- point sources (can’t locate the cause, it’s everywhere) Atmospheric deposition Agricultural runoff (fertilizer, soil erosion) Septic systems

73. STEPS OF E U T R O PH I C A T I ON 1. Fertilizer flows into water causing…. Increased plant growth on the surface o f water, causing….. Decreased light in lower levels of water 4. Plants in lower levels of water will die 5. Decay using up O 2 and increasing CO 2 6. Death of fish and other animals

74. Before increases in nutrients

75. Acceleration of Eutrophication

76. Results of Eutrophication

77. Photo 1: Algal bloom in a lake. Algal bloom in a lake.

78. Algal blooms otherwise called " N uisance algae " or "harmful algal blooms" are toxic to plants and animals . Fish mortality du e t o lack of oxygen .

79. Blue Baby Syndrome - An illness that begins when large amounts of nitrates in water are ingested by an infant and converted to nitrite by the digestive system. He nitrite then reacts with ox hemoglobin (the oxygen-carrying blood protein) to form metheglobin, which cannot carry oxygen. If a large enough amount of metheglobin is formed in the blood, body tissues may be deprived of oxygen, causing the infant to develop a blue coloration of their mucous membranes and possibly digestive and respiratory problems. This condition is also known as methemoglobinemia.

80. : Overgrowth of floating aquatic plants.

81. Preventive Measures Waste water must be treated before its discharge into water stream to limit the nutrient value. Minimize the amount of nitrogen and phosphorus from the receiving body and dilution of water is advisable. One should minimize the use of chemical fertilizers or better still do away with them and use natural ones instead. Be sure not to have the fields close to the water bodies. Take extra care while using fertilizers during monsoons as due to run - off, they get transmitted to the water bodies. Then , they can cause blockage of water ways.

82. Preventive Measures Algal growth need to be removed time to time. Use of certain chemicals like lime, alum, iron, sodium aluminates precipitate additional phophorus . Other physicochemical methods can be adopted to remove O2.