22 March is World Water Day Presented by Dr. B. Victor., Ph. DEmail : firstname.lastname@example.org Blog: bonvictor.blogspot.com
Introduction Chemical structure Life – supporting Global water cycle functions of water. Kinds and sources of Water is vital to human water pollution life Health impacts of water Global water issues pollution Global distribution of Water footprint water Water pollution episodes Properties of water Remedial measures
The earth is the only planet with water. The planet earth is also called the ‘blue planet’ due to the presence abundant water on its surface. The earth is the only planet that supports life.Evidences:1.water occurs on its surface as liquid, ice and gas.2.ocean covers 71% of the globe.3.Freshwater cover les than 1%.4.Ice sheets cover polar region.5.Glacier’s are found in higher mountains.
Water covers approx.71 % of the planet earth and constitutes 60-70 % of the living world. The existence of life on earth is not possible without water. The environmental system within which we live is dependent on water.
Human consumption- (drinking and cooking) Food production (irrigation) Personal hygiene Sanitation Industrial production Energy generation Economic development Environmental protection.
An average adult human body contains 42 liters of water. Water is required for digestion and absorption of food. Water transfers oxygen and nutrients to the cells. Water carries metabolic wastes. Water act as a natural cooling system.
Water shortage - levels of available water do not meet minimum requirements. Water scarcity – the relationship between demand for water and its availability. Water stress – decline in water quality. Water security – access to adequate quantity and safe quality.
Water is facing a crisis today. Water scarcity affects all social and economic sectors. There are concerns that water will increasingly be the cause of violence and even war. Water is recognized as one of the key limiting resources of this millennium.
Approx. 700 million people in 43 countries suffer as a result of water scarcity. Nearly 1 billion people lack safe drinking water. Half of the world’s 500 major rivers are polluted. 75% of India’s lakes and rivers are too polluted for safe use.
The total amount of water on the earth is about 326 million cubic miles of water. The needs for water rise along with population growth, urbanization and increases in the number of households and industrial uses.
97.200% sea water 02.014% ice caps and glaciers 00.600% ground water 00.009% surface water 00.005% soil moisture 00.001% air moisture
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: in liquid form, water takes the shape of its container. Gases: in vapor form water has no definite size.
Ocean Water: salt water is found in the oceans and seas. Fresh Surface Water: fresh water is found in rivers, streams, lakes and ponds. Ground water: Ground water is stored in underground aquifers. Water in aquifer remains there for an average of 1,400 years!
A water molecule has one oxygen atom and two hydrogen atoms. The two hydrogen atoms bound to one oxygen atom to form a ‘V’ shape at an angle of 105 degree. The length of the bond between the oxygen and the hydrogen is 95.84 pm (picometre). The chemical formula for water is H2O, meaning two hydrogen atoms covalently bonded to one oxygen atom.
Water is colorless, tasteless and odorless. Water is a great solvent. Water exists as a liquid, in rivers and seas, a solid, as snow and ice, and as a gas, as clouds or steam. Water can absorb a large amount heat(high specific heat capacity). Water can stick together into beads and drops( surface tension). Water flows and erodes the surface of the earth.
There are TWO overlapping water cycles in nature.
Water evaporates from water bodies like seas, and oceans, lakes and rivers. Water vapor cools and condenses in the clouds. Water precipitates in the form of rain and snow which fall on the soil. Runoff and accumulation forms fresh water lakes, streams, ponds and groundwater.
Evaporation – the process by which water changes from liquid to gaseous state. Condensation – the process by which a gas changes to a liquid. Precipitation – clouds in the air drop rain on land. Transpiration – the process by which plants release water vapor thro’ leaves. Accumulation – water gets collected in oceans , seas and lakes.
This cycle refers to volume of water content in the body of an organism. Aquatic plants and freshwater animals absorb water from the surrounding medium by osmosis. Trees absorb water from the moist soil thro’ roots. Land animals receive water by feeding and drinking. Plants loose water by transpiration thro’ leaves. Animals loose water by sweating and elimination. After death water returned to the environment by bacterial decomposition.
Pure water = 7.0 pH Rain from unpolluted atmosphere = 6.0 pH Natural rain water = 5.6 pH Acidic rain water = 4.5 pH Rain near urban areas = 4.0 pH Rain from fog clouds = 1.7 pH
Surface water pollution - pollution of lakes, rivers and oceans Groundwater pollution - pollution of aquifers below soil. Microbial pollution – pollution by bacteria, viruses, protozoa and parasitic worms. Oxygen depletion pollution – pollution by biodegradable organics. Nutrient pollution – pollution by plant nutrients (nitrates, phosphates) Suspended matter pollution – pollution by soil, silt Chemical pollution - pollution by pesticides, fertilizers, industrial solvents, oil Thermal pollution- pollution by warm water, waste heat
Point Sources – A single definable source of the pollution, e.g. a factory, a sewage plant, etc.- pollution is easy to monitor and control, Non-point sources – No one single source, but a wide range of sources, e.g. runoff from urban areas, or farmland.-Pollution is more difficult to monitor and control.
Non-persistent pollutants can be broken down by natural chemical reactions or by natural bacteria into simple, non- polluting substances such as carbon dioxide and nitrogen. e.g. wood, paper, biological wastes More load of degradable pollutants can lead to low oxygen levels and eutrophication. But this damage is reversible.
Organic chemical substances are persistent that degrade very slowly or cannot be broken down at all. They may remain in the aquatic environment for longer periods of time. The damage is irreversible and is the most rapidly growing type of pollution.
Industries effluents contain heavy metals , resin pellets, organic toxins, oils, nutrients, and solids.
Impact of Microbial water pollution No. of people lack access to safe drinking water = Over 1 billion. No. of people lack adequate sanitation = 2.6 billion . This has led to widespread microbial contamination of drinking water. Deaths due to water-associated infectious diseases =up to 3.2 million people per year. (approx. 6% of all deaths globally). Deaths due to diseases caused by inadequate water, sanitation, and hygiene = 1.8 million people.
excessive amounts of plant nutrients=P,N,C. Excessive growth or ‘blooms of algae’ Algal blooms leads to oxygen depletion. Hypoxia leads to mass fish kills. Degradation of water and habitat quality.
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 scarcity. Water scarcity is already a problem in many countries.
50% of the world’s population lives on or within 160 miles of shore. Fourteen billion pounds of garbage, mostly plastic, is dumped into the ocean every year. For every 1 million tons of oil that is shipped, about 1 ton is spilled. More oil is seeped into the ocean each year as a result of leaking cars and other non-point sources
Asian rivers are the most polluted in the world. River Ganges in India is one of the most polluted rivers in the world. Approximately 46% of the lakes in America are too polluted for fishing, aquatic life, or swimming.
The amount of plastic waste has been increasing about 10% each year for the past 20 years. Over 1 million seabirds are killed by plastic waste per year. Over 100,000 sea mammals and countless fish are killed per year due to pollution.
“Water contributes much to health” - Hippocrates ( 460 – 377 B.C )
Pesticides - damage nervous system and also cause cancer. Lead – affects central nervous system . Fluorides – damage teeth and the skeleton. Nitrates – cause blue – baby syndrome in infants. Petrochemicals – cause cancer. Arsenic – damage liver and nervous system, skin cancer. Heavy metals – damage nervous system and kidneys.
Toxicity- acute / chronic – damages aquatic / human lifeChanges in Sub-lethal toxicityWater chemistry Endocrine disruption / Changes in biodiversity Effects of water Acidity/alkalinityEutrophication pollution Changes pH regime Altered water Spread of microbial temperature diseases Deoxygenation- Lack of O2 in water
Diseases caused by the ingestion ofcontaminated water.
Water – based diseases-skin contact with aquatic intermediate host in water. Guinea worm infections Schistosomiasis.
Each year, there are about 250 million cases of water- related diseases. It is estimated that at least 1.5 million children under the age of 12 die annually due to water pollution. 1.4 million people die each year in India from water pollution.
Water footprint measures the consumption and contamination of freshwater resources. It was first introduced by Hoekstra in 2002 to provide a consumption- based indicator of water use. Water footprint differs around the world and depends on climate, soil types, irrigation methods and crop genetics.
Your water footprint extends beyond the average 80-100 gallons of water you use everyday. A product water footprint is the total volume of freshwater consumed, directly and indirectly, to produce a product.
Each person daily needs 20 to 50 liters for drinking and hygiene. Since 1970, global demand for water has risen nearly 2.4 % per annum. 20 developing countries are classified as ‘water scarce’.
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. Spread the word.
“ Water has the power to move millions ofpeople – let it move us in the direction ofpeace”. -Mikhail Gorbachev, president, Green Cross International.
Dr.B.Victor is a highly experienced postgraduate professor from the reputed educational institution- St. Xavier’ s College(autonomous), Palayamkottai, India-627001. He had been 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. He retired from service on 2008. Send your comments to : email@example.com