Water Pollution

Water Pollution

Some of the stuff that it dissolves / suspends is good for us

Others, not so good

Can you name 5 things that dissolve in water?

Know of any 2 that can be called ‘pollutants’ – those dangerous to life ?

If we drink polluted water, we can get sick

Figure out some pollutants

C T S K

+ + _ _ _ _ _ _ _

Led ZeppelinBlack Sabbath

Deep PurpleIron Maiden _ _ _ _ _ _ _ _ _ _

+ _ _ _ _ _ _ _GH

Sounds like + _ _ _ _ _ _ _ _Clue: toothpaste

Figure out some pollutants

C T S K

+ + ARSENIC

Led ZeppelinBlack Sabbath

Deep PurpleIron Maiden HEAVY METAL

+ NITRATEGH

Sounds like + FLUORIDEClue: toothpaste

How do we know that water is polluted?

Sometimes it stinks……but not always

Sometimes polluted water changes colour…..but not always

Sometimes it tastes different ……..but not always

How do we know that water is polluted?

Water pollution can be confirmed only by testing it in a lab

Sources of water pollution are generally grouped into two categories

Non-point source of pollution: Contamination gathered by water over a large area.

Point-source of pollution: Contaminants enter a waterway at a discrete point

Water can get polluted naturally

When water seeps into the ground, it absorbs different substances depending on the type of soil and rock that it flows through.

Water can get polluted naturally

Some of these substances (arsenic, iron, fluoride etc) can be harmful to health

Natural pollution is a non-point source of pollution

Arsenic

Fluoride

Natural pollution can introduce chemicals that collect in our bodies. Over time this can cause chronic problems and even

life – threatening diseases.

In groundwater

In groundwater

Does Man Pollute Water?

“ If you had a bottle of life-preserving fluid on which your life depended,

would you pour into it all your sewage and rubbish, along with any other

poisonous chemicals you could find? And yet, that is exactly what we are

doing to our water supply – all over the world.”

This is what a young person like you has to say:

The various ways in which man pollutes water Untreated or inadequately treated municipal sewage

Yamuna, when it leaves Delhi, resembles a sewer full of the city’s wastes. A few hundred kms downstream is Agra, where

this ‘sewer’ is the main municipal drinking water source.

YUCK!! eutrophication

An example of Point source of pollution

Reaches ground water bodies

Untreated sewage seeps in and contaminates groundwater aquifers

Such aquifers show a higher than acceptable level of nitrate content

The various ways in which man pollutes water Untreated or inadequately treated municipal sewage

An example of Point source of pollution

The various ways in which man pollutes water

When garbage is dumped in a landfill, toxic chemicals leach into the soil and groundwater.

Dumping garbage in surface water bodies

Over 10 million people bathe in the Ganga daily!

The various ways in which man pollutes water

Washing and bathing introduces phosphates and other chemicals into water

The various ways in which man pollutes water

Agriculture is a major source of groundwater

contamination.

AgricultureAn example of Non- Point source of pollution

dissolve in irrigation water or rainwater.

They contaminate surface water and groundwater with pollutants like nitrates, phosphates and non degradable synthetic organic pollutants

The various ways in which man pollutes water

Industry

Agro industries – their wastes have high concentration of dissolved organic matter

Chemical Industries – If their wastes are not treated properly, the chemicals can destroy our soil and water resources.

Petroleum refining – water used in the process needs to be separated from all the oil before releasing it into nature……but is that done??

An example of Point source of pollution

Can you name any Agro Industry?sugar, food processing, pulp and paper, distilleries

Name some Chemical industries

Minamata disease

The various ways in which man pollutes water

Industry

Thermal power plants – water is needed to cool the process.

The water gets hot and when it’s released into a larger water body, it upsets the ecology by modifying the delicate temperature balance.

This is called ‘Thermal pollution’

An example of Point source of pollution

Effluent treatment plants

Liquid wastes from an industry are treated in effluent treatment plants.

Large industries would have in-house effluent treatment plants

It’s expensive for small industries to go in for such plants individually

In some industrial estates, a group of small industries have a common effluent treatment plant.

A RE-CAP

Water can be polluted by man

Water can be polluted naturally

Sewage in our water bodies Garbage dumps Washing and bathing Pesticides and fertilizers Industries

Divide the class into 5 teams

Draw as many dashes as in the name of a water pollutant or a pollution cause

Team A starts. They guess a letter. The teacher puts in the letter at the correct place, if it is there in that name.

Else, the letter is written down on one side.

A maximum of 10 wrong guesses are allowed.

The team gets as many points as letters on the side (maximum of 10).

The team with the lowest number of points wins

Hangman

Eutrophication (pronounced as you-tro-fi-kay-shun)

When wastes with high organic content (such as sewage wastes) are dumped into a water body like a lake or pond, eutrophication can occur, killing all life in the water body.

Organic wastes are rich in nutrients (nitrates and phosphates)

They stimulate excessive plant growth – especially weedy species

Eutrophication

On dying, the plants further add to the organic waste in water.

Microorganisms that decompose the organic material in water use up a lot of dissolved oxygen.

This depletes the available oxygen in the water and upsets the ecological balance, since fish and other life forms perish without adequate oxygen.

Eventually all the oxygen is used up.

Eutrophication

Anaerobic organisms then attack the organic wastes, releasing gases such as methane and hydrogen sulphide.

The result is a foul smelling, waste filled body of water, quite like many of the lakes in India.

These water bodies are also natural groundwater recharge system and their contamination also leads to groundwater pollution.

Minamata disease

Industrial wastewater from the Chisso corporation (manufacturing fertilizers and other chemicals) was released into the Minamata Bay in Japan

The waste water was rich in methyl mercury

Mercury content in shellfish in that region increased

People ate the shellfish and the cats ate the leftovers

Strange things started to happen – cats had convulsions and died, crows fell from the sky, dead fish floated..

Young children had convulsions and difficulty in walking and speaking People died Investigation showed organic mercury poisoning affecting the nervous system

First discovered in 1956

Lawsuits and claims continue till today

Did you know? One mercury thermometer can contaminate up to 95,000 litres of water to beyond the drinking water standard.