Permissible limits of water pollutants in drinking water.

PERMISSIBLE LIMITS OF WATER POLLUTANTS ACCORDING TO ISI & WHO-Ishan Trivedi.- TIFAC.

THE NEED TO ESTABLISH LIMITS…..

What is the need to

establish permissible

limits ?

That is because….

.

3

WATER IS PRECIOUS AND SCARCE RESOURCE

Only a small fraction (about 3%) is fresh water

India is wettest country in the world, but rainfall is highly uneven with time and space (with extremely low in Rajasthan and high in North-East)

On an average there are only 40 rainy days Out of 4000 BCM rainfall received, about 600

BCM is put to use so far Water resources are over-exploited resulting

in major problems. To enable proper legislation by establishing

standards and punish the polluting industries.

THE WATER (PREVENTION AND CONTROL OF POLLUTION) ACT, 1974 The need for legislating the act was felt in the year 1962,

it was the same year when Independent India fought its first war with China. A committee was set up in 1962 to draw a draft enactment for the prevention of water pollution.

The reason for legislating the act was given as “ The problem of pollution of rivers and streams has assumed considerable importance and urgency in recent years as a result of the growth of industries and the increasing tendency to urbanization”.

The object for legislating the act was given as “ It is, therefore, essential to ensure that the domestic and industrial effluents are not allowed to be discharged into the water courses without adequate treatment as such discharges would render the water unsuitable as sources of drinking water as well as for supporting fish life and for use in irrigation. Pollution of rivers and streams also causes increasing damage to the country’s economy.”

‘POLLUTION’ DEFINED IN THE ACT It means such contamination of water or such

alteration of the physical, chemical or biological properties of water or such discharge of any sewage or trade effluent or of any other liquid, gaseous or solid substance into water (whether directly or indirectly) as may, or is likely to, create a nuisance or render such water harmful or injurious to public health or safety, or to domestic, commercial industrial agricultural or other legitimate uses, or to the life and health of animals or plants or of aquatic organisms. (section 2(e) of the Act)

SAFE DRINKING WATER

Free from pathogenic organisms Clear Not saline Free from offensive taste or smell Free from compounds that may have

adverse effect on human health Free from chemicals that cause corrosion of

water supply systems

WATER QUALITY PARAMETERS Physical parameters Chemical Bacteriological

BUREAU OFINDIAN STANDARDSIS 10500-1991DRINKING WATER STANDARDS

Parameters Desirable limit

Permissible limit

Colour Hazen unit 5 25

Turbidity-NTU 5 10

pH 6.5-8.5 6.5-8.5

Hardness (as CaCO3)mg/l

0.3 1

TDS 500 2000

BUREAU OFINDIAN STANDARDSIS 10500-1991

Parameters Disirable limit

Permissible limit

Nitrate mg/l 45 45

Chloride mg/l 250 1000

Flouride mg/l 1 1.5

Arsenic mg/l 0.05 0.05

Aluminium mg/l 0.03 0.2

ESSENTIAL BACTERIOLOGICAL STANDARDS, ISI & WHO

Characteristics Number / 100 ml

Treated water in distribution system

Faecal coliform zeroTotal coliform not more than 10 Total coliform should not be detectible in two consecutive samples

WHO STANDARDS, DRINKING WATER, 1993.

REASONS OF VARIOUS POLLUTANTS IN WATER AND RELATED ISSUES….

COLOUR

Reason: May be due to the Presence of organic

matter,metals(iron, manganese) or highly coloured industrial waste.

Issues: Aesthetically displeasing. Desirable that drinking water be colourless. Desirable limit, 5 Hazen unit. Permissible limit 25 Hazen Unit.

TASTE AND ODOUR

Reason: Mainly due to organic substances ,Biological

activity, industrial pollutionIssues: Taste buds in the oral cavity specially detect

inorganic compounds of metals like magnesium, calcium, sodium, copper, iron and zinc

Water should be free from objectionable taste and odour.

TURBIDITYReason: Caused by suspended matterIssues: High level turbidity shield and protect bacteria

from the action of disinfecting agents Desirable limit-5 NTU should be below 1 NTU when disinfection is

practiced Permissible limit-10 NTU

In picture: 5,50, 500 NTU

PH It is the measure of hydrogen ion concentration Neutral water pH-7 Acidic water has pH below 7 Basic water has pH above 7 Desirable limit 6.5-8.5 Issues: Beyond this limit the water will affect the mucous

membrane and water supply system

REASONS:SUBSTANCES THAT CHANGE PH OF WATERAcidicIndustriesSugar - 5 – 6 Distillery 3 -

4Electro- Plating unit

2.5-4Pickle 2 - 3

Basic

Paper 8 – 10Textile 8.5-11Fertiliser 6.5- 9Oil Refine- ries 6.5-

9.5

HARDNESS

Capacity of water for reducing and destroying the lather of soap

It is total concentration of calcium and magnesium ions

Types and reasons: Temporary hardness – Bicarbonates of

Calcium and Magnesium Permanent hardness – Sulphates, chlorides

and nitrates of calcium and magnesium

HARDNESS – CONTD…

0 – 50 mg/l - soft 50 – 150 mg/l - moderately hard 150 – 300 mg/l - hard 300 above - very hard Surface water is softer than ground waterIssues: Causes encrustations in water supply

structures Hard water is difficult to drink.

ALKALINITY Capacity to neutralise acid Presence of carbonates, bi-carbonates and

hydroxide compounds of Ca, Mg, Na and K Alkalinity = hardness, Ca and Mg salts Alkalinity > hardness - presence of basic salts, Na,

K along with Ca and Mg Alkalinity < hardness – neutral salts of Ca & Mg

present

IRON

One of the earth’s most plentiful resource.

Issues: High iron causes brown or yellow staining

of laundry, household fixtures. Metalic taste, offensive odour, poor tasting

coffee Cause iron bacteria.

Acceptable limit – 0.3 mg / l

CHLORIDEReasons: Dissolution of salt deposit Discharge of effluents Intrusion of sea waterIssues: Not harmful to human beings Regarding irrigation – most troublesome anion Acceptable limit - 250 mg/l

NITRATEReasons: Increasing level of nitrate is due to Agricultural

fertilizers, manure,animal dung, nitrogenous material ,sewage pollution

Issues: (blue baby diseases to infants)

Maximum permissible limit 45 mg / l

FLUORIDEReasons: Occurs naturally

Issues: Long term consumption above permissible level can

cause – dental fluorosis (molting of teeth) Skeletal fluorosis Acceptable limit – 1 mg / l Maximum permissible limit – 1.5 mg / l Remedy – 1) Defluoridation 2) Mixing Fluoride free water 3) Intake of vitamin C,D, calcium,

antioxidants

FLUORIDE CAUSES

Three types of Fluorosis

1. Dental Fluorosis2. Skeletal Fluorosis3. Non-skeletal

Fluorosis

ARSENIC

Reasons: Occur in ground water from arseniferous belt Industrial waste, agricultural insecticideIssues: High arsenic causes 1) various type of

dermatological lesions, muscular weakness, paralysis of lower limbs, can also cause skin and lung cancer

Acceptable limit – 0.05 mg / l

PESTICIDES

Reasons: Uncontrolled, excessive use.

Issues: Cancer Birth defects Blood disorder Nervous disorder Genetic damage

HEAVY METALSReasons: Present as mineral in soil and rocks of earth Human activities : Battery – Lead & Nickel Textile - Copper Photography – Silver Steel production – Iron

Issues: The most pollutans heavy metals are Lead, Cadmium, Copper, Chromium, Selenium and

Mercury.

Lead In humans, Long term exposure can occur acute or chronic damage to the nervous system on humans.

Cadmium In humans, long-term exposure is associated with renal disfunction. High exposure can lead to obstructive lung disease and has been linked to lung cancer,and damage to human’s respiratory systems.

Copper is an essential substance to human life, but in high doses it can cause anemia, liver and kidney damage, and stomach and intestinal irritation.

Effect of the Mercury is to cause damage to the brain and the central nervous system.

RESIDUAL CHLORINE

Chlorine added to water forms hypochlorite ions and hypochlorite acids

Chlorine demand – Quantity required for killing micro-organisms and reacting with ammonia, organic compounds etc.

To take care of post contamination Desirable – 0.2 mg / liter

COMMON PROBLEMS

Visible effects Reason

Iron taste, change in colour after exposure to atmosphere, change in colour of cloths,utensils Oily appea- rance on top of water body

Iron

Soap not lathering hardness

Brownish black streaks on teeth `Fluride

Growth of Algae Nitrate, phosphate

Fish kills Low pH less DO

Salty taste chloride

COMMON PROBLEMS CONTD.

Visible effects Reasons

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

ISSUES WITH INDUSTRIAL POLLUTANTS ON AQUATIC ECOSYSTEM. Dissolved Solids : Scale buildup in pipes, valves, and filters, reducing performance and

adding to system maintenance costs.

Suspended Solids :Decrease in penetration of light at ocean beds (Benthic zone) can cause

destruction of photosynthetic plants and bacteria at ocean bed which in turn can destroy entire ecosystem.

pH: Destruction of pH sensitive aquatic life. Destruction of pH sensitive rocks.

Temperature:Destruction of temperature sensitive organisms in local beds.Decrease in DO, killing temperature resistant organisms too.

Oil:Decrease in DO can cause destruction aquatic animals and birds.

ISSUES WITH INDUSTRIAL POLLUTANTS ON AQUATIC ECOSYSTEM CONTD….

Ammoniacal nitrogen:Hatching and growth rates of fishes may be affected. In the structural development, changes in tissues of gills (Hyperplasia), liver, and kidneys may also occur. Toxic concentrations of ammonia in humans may cause loss of equilibrium, convulsions, coma, and death.

Organic carbon:Causes increase in BOD, COD and thus decrease in DO killing

aquatic life.

Pesticides:Direct destruction.Bioaccumulation Biomagnification

ISSUES WITH INDUSTRIAL POLLUTANTS ON AQUATIC ECOSYSTEM CONTD…. Heavy metals:The most pollutans heavy metals are Lead, Cadmium, Copper, Chromium, Selenium and

Mercury.

Lead In humans, Long term exposure can occur acute or chronic damage to the nervous system on humans.

Cadmium In humans, long-term exposure is associated with renal disfunction. High exposure can lead to obstructive lung disease and has been linked to lung cancer,and damage to human’s respiratory systems.

Copper is an essential substance to human life, but in high doses it can cause anemia, liver and kidney damage, and stomach and intestinal irritation.

Effect of the Mercury is to cause damage to the brain and the central nervous system. Selenium causes to damage to circulatory tissue, and more severe damage to the nervous

system.

Nitrates and nitrites:Eutrophication.

Dissolved phosphates:Eutrophication.

Cyanide:weight loss, thyroid effects, nerve damage to humans.

EUTROPHICATION

THUS,

It is necessary to establish the

limits…

Thank you.

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