Presented by
Dr. B. Victor
About the presenterAbout the presenter
Dr.B.Victor is a highly experienced postgraduate biology teacher, recently retired from the reputed educational institution St. Xavier’ s College, Palayamkottai, India-627001.
He was the dean of sciences and assistant controller of examinations.
He has more than 32 years of teaching and research experience
He has taught a diversity of courses ranging from pre- university to post graduate classes.
Send your comments to : [email protected]
Water is essential to life on earth.
Importance of waterImportance of waterOrganisms are composed of much water––
70%-95%
Supportive external environment for aquatic organisms
Cellular medium within which biochemical reactions can occur
Transport medium for food, oxygen, and other things needed by cells
Means of support-Turgid plant cells/Hydrostatic animal support systems
Three forms of Water. Three forms of Water.
Solids: When water becomes very cold and freezes it will change from a liquid to a solid. It has a definite form and shape.
Liquids: When water takes the shape of its container it is in a liquid form.
Gases: When water is seen in a vapor form and has no definite size or shape it is in a gas form.
Distribution of global waterDistribution of global water
The earth's water supplyThe earth's water supply
97.2% of the Earth's water supply is salt water.
Only 2.8% is fresh water!
Salt and freshwater relationshipSalt and freshwater relationship
World Water SupplyWorld Water Supply
97.200% salt water in the oceans 02.014% ice caps and glaciers 00.600% groundwater 00.009% surface water 00.005% soil moisture 00.001% atmospheric moisture
Earth as water planetEarth as water planet
Earth is often referred to as `the water planet'.
Earth is unique amongst planets of our solar system because of its abundant water - in oceans, in the atmosphere, in glaciers and as fresh water on land.
Without water, life could not exist.
The earth's freshwater supplyThe earth's freshwater supply
Only about 3% of Earth's water is fresh. Two percent of the Earth's water (about 66% of
all fresh water) is in solid form, found in ice caps and glaciers.
One percent of all the Earth's water in a form useable to humans and land animals.
This fresh water is found in lakes, rivers, streams, ponds, and in the ground. (A small amount of water is found as vapor in the atmosphere.)
Distribution of waterDistribution of water Ocean Water: The vast majority of water
on the planet is the salt water in the oceans and seas.
Fresh Surface Water: This is the fresh water in rivers, streams, lakes, ponds and similar bodies of water.
Groundwater: The majority of the planet's liquid freshwater is stored in underground aquifers. Water that enters an aquifer remains there for an average of 1,400 years!
Water : A precious Natural ResourceWater : A precious Natural Resource
We use water for drinking, irrigation, industrial purposes and energy production. Water use
agriculture and energy production - 80%
industry and public use - 20%
Water is used in many waysWater is used in many ways
as a nourisher of plant and animal life, a bearer of food, a prime element of industrial processes,
and a medium for transportation
Significance of waterSignificance of water
Water is an integral part of life on this planet. It is an odorless, tasteless, substance that
covers more than three-fourths of the Earth's surface.
Most of the water on Earth, 97% to be exact, is salt water found in the oceans.
We can not drink salt water or use it for crops because of the salt content.
We can remove salt from ocean water, but the process is very expensive.
Hydrologic cycle - water cycle
Hydrologic cycle - water cycle
Two main processes: precipitation and evaporation
Powered by energy from the sun
Hydrologic cycle purifies water
Global hydrologic cycle Global hydrologic cycle
Water Cycle Water Cycle
Saltwater evaporates from sun's energy producing fresh water in clouds; leaves salts in ocean.
Water vapor cools and condenses to
precipitation over oceans and land.
Runoff forms fresh water lakes, streams, ponds, groundwater, and is held in plants and transpired.
Water consumption/ countries Water consumption/ countries
Human activity disrupts local water cyclesHuman activity disrupts local water cycles
Irrigation Clear cutting of forests Watershed disturbance Loss of minerals through runoff Desertification
Water consumption/useWater consumption/use
Daily use of waterDaily use of water
Pollution of waterPollution of water
Water Pollution
Where do Water pollutants come from?Where do Water pollutants come from?
Point Sources – A single definable source of the pollution, e.g. a factory, a sewage plant, etc. Point-source pollution is usually monitored and regulated.
Non-point sources – No one single source, but a wide range of sources, e.g. runoff from urban areas, or farmland. Non-point sources are much more difficult to monitor and control.
Pollution of Water Pollution of Water
1. Industrial pollution2. Surface pollution3. Groundwater contamination4. Sewage pollution5.Oil pollution6.Thermal pollution
Sources of Water pollutionSources of Water pollution
Water pollutantsWater pollutants
Industrial EffluentsThis waste water may contain acids, alkalis, salts, poisons, oils and in some cases harmful bacteria.
Mining and Agricultural WastesMines, especially gold and coal mines, are responsible for large quantities of acid water.
Agricultural pesticides, fertilizers and herbicides may wash into rivers and stagnant water bodies.
Sewage Disposal and Domestic WastesSewage as well as domestic and farm wastes were often allowed to pollute rivers and dams.
Water pollutionWater pollution
Non-persistent (degradable) Water pollutants
Non-persistent (degradable) Water pollutants
Domestic sewage Fertilizers Some industrial wastes
Non-persistent (degradable)water pollutantsNon-persistent (degradable)water pollutants
These compounds can be broken down by chemical reactions or by natural bacteria into simple, non-polluting substances such as carbon dioxide and nitrogen.
if the pollution load is high, this process can lead to low oxygen levels and eutrophication.
This damage is reversible.
Persistent Water pollutantsPersistent Water pollutants
some pesticides (e.g., DDT, dieldrin) some leachate components from landfill sites
(municipal, industrial) petroleum and petroleum products PCBs, dioxins, polyaromatic hydrocarbons
(PAHs) radioactive materials such as strontium-90,
cesium-137, radium-226, and uranium metals such as lead, mercury, cadmium
Persistent Water pollutantsPersistent Water pollutants
This is the most rapidly growing type of pollution
This includes substances that degrade very slowly or cannot be broken down at all;
They may remain in the aquatic environment for years or longer periods of time.
The damage they cause is either irreversible or repairable only over decades or centuries
Other water quality pollutantsOther water quality pollutants
warm water from cooling towers (thermal pollution)
floating debris garbage foam These physical pollutants interfere mainly
with the usability and/or aesthetic appeal of the water. In certain cases, thermal pollution can kill fish.
1. Classes of Water pollutants 1. Classes of Water pollutants
Pathogens Bacteria, Viruses, Protozoa, Parasitic Worms, Colliform Bacteria Used As Indicators Of Water Quality
Oxygen Demanding Wastes Organics That Are Decomposed By Bacteria And That Use A Lot Of O2, Dissolved Oxygen (DO) Decreases, And BOD Increases
Water Soluble Inorganic Chemicals Acids, Salts, Toxic Metal Compounds Like Mercury, And Lead.
Inorganic Plant Nutrients Water Soluble Phosphates, Nitrates => Algal Blooms, Decreased Dissolved O2, Increased BOD, Methemoglobinemia (="blue baby syndrome")
2. Classes of Water pollutants2. Classes of Water pollutants
Organic Chemicals Oil, Gas, Plastics, Pesticides, Cleaning Solvents, Detergents, Etc.
Sediment & Suspended Mater Insoluble Soil Particulates & Other Solids. Clouds The Water, Decreasing Photosynthesis, Carries Pesticides And Disrupts Aquatic Food Webs.
Radioactive Isotopes Are Biologically Amplified To Higher Concentrations In The Food Chain. Ionizing Radiation & Birth Defects, Cancer.
Warmed Water From Power Plants, Decreases DO And
Increases Susceptibility To Diseases And Parasites And Toxic Wastes.
Alien Species Zebra Mussels, Asiatic Catfish, Sea Lamprey, etc. Out compete Native Species And Ultimately Decrease Biodiversity
Industrial Water pollution Industrial Water pollution
Industries discharge a variety of pollutants in their wastewater including heavy metals , resin pellets, organic toxins, oils, nutrients, and solids.
Over 1 billion people lack access to safe water supplies, while 2.6 billion people lack adequate sanitation. This has led to widespread microbial contamination of drinking water.
Water-associated infectious diseases claim up to 3.2 million lives each year, approximately 6% of all deaths globally.
Microbial contaminationMicrobial contamination of water
Eutrophication Eutrophication
Increases in nutrient loading may lead to eutrophication .
Organic wastes such as sewage impose high oxygen demands on the receiving water leading to oxygen depletion.
DroughtDrought Drought causes more damage and
suffering than any other natural disaster.
80 countries experience droughts lasting more than 1 year.
According to the UN, almost 500 million people, in 31 countries (~40% of the world’s population) experience chronic water shortages today.
Flooding: oversupply of water
Flooding: oversupply of water
Water Logged Soil Nutrient Leakage Topsoil Erosion
Acid rainAcid rain
Acid rain is formed when moisture in the clouds mixes with sulfur or nitrogen in the air.
Acid rain includes rain, sleet or snow with a pH level that falls below 5.6 (normal rainwater).
The sulfur and nitrogen get into the air by the burning of fossil fuels such as coal and gasoline. The average pH of rainfall is 4.3.
River pollutionRiver pollution
Asian rivers are the most polluted in the world.
Three times as many bacteria from human waste as the global average
20 times more lead than rivers in industrialized countries.
Mass fish killsMass fish kills
Plastic waste in waterPlastic waste in water
Each year, plastic waste in water and coastal areas kills up to:
100,000 marine mammals, 1 million sea birds, and countless fish.
Water borne diseasesWater borne diseases
Diseases caused by the ingestion of water contaminated with pathogenic bacteria, viruses, or parasites include:
cholera typhoid schistosomiasis dysentery and other diarrheal diseases
Disease burden from water pollution Disease burden from water pollution
Water-associated infectious diseases claim up to 3.2 million lives each year, approximately 6% of all deaths globally.
The burden of disease from inadequate
water, sanitation, and hygiene totals 1.8 million deaths and the loss of greater than 75 million healthy life years.
Water and sanitation
Water and sanitation
It is well established that investments in safe drinking water and improved sanitation show a close correspondence with improvement in human health and economic productivity.
Each person needs 20 to 50 liters of water free of harmful chemical and microbial contaminants each day for drinking and hygiene.
There remain substantial challenges to providing this basic service to large segments of the human population.
Oil Pollution of water Oil Pollution of water
Both Point and Nonpoint Sources Largest source of oil pollution is pipeline
leaks and runoff– 61% ocean oil pollution river & urban
runoff– 30% intentional discharges from tankers– 5% accidental spills from tankers
Remedial measuresRemedial measures
Locate the point sources of pollution. Work against acid rain. Educate your community. Ensure sustainable sewage treatment. Watch out for toxins. Be careful what you throw away. Use water efficiently. Prevent pollution . Think globally, act locally.
Thank youThank you
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