It includes pH ,fluorine , nitrate , sulphate etc and their sources, concentration, and effects on usability.

1. CHEMICAL PARAMETERS
OF WATER QUALITY
PRESENTED BY
NITIN
MSC. SECOND YEAR
CENTRAL UNIVERSITY OF KERALA

2. INTRODUCTION:-
•Water is the second most important need for life to exist after air. So extensively defined in
scientific literature.
•Water quality is the measure of the condition of the water relative to the requirements of one
or more biotic species to any human need or purpose.

3. Classification of water quality parameters
Water quality parameters can be classified in a number of ways , but most
often are grouped as physical, chemical and biological.
• Physical:- taste , order , color , temperature, electrical conductivity , etc.
• Biological:- Bacteria, viruses, algae etc.
• chemical :- Inorganic (calcium, magnesium , sulphate, iron).

4. CHEMICAL PARAMETERS OF WATER QUALITY
•pH :-
• It is defined as the negative logarithm of the
hydrogen ion concentration . Indicates strength of
an acidic or a basic solution .
• Safe ranges of pH for drinking water are from 6.5
to 8.5 for domestic use and living organisms need.
• Low (<4) pH indicate corrosive water that will
tend to dissolve metals and other substances that
it contacts.
• High values of pH (≥8.5) indicate alkaline water
that, on heating, will tend to form a scale.

5. • HARDNESS:- Ca and Mg combine with soap to form an insoluble precipitate and thus hamper
the formation of a lather, and also affects suitability of water for use in textile and paper
industries, steam boilers and water heater .
• USGS classification of hardness (mg/L as CaCO3) 0-60- soft, 60-120= moderately hard ,121-
180_ Hard and more than 180 very hard.
Iron (Fe) :- Originate from igneous and sedimentary rocks more than 0.1 mg/l precipitates
after the exposure to air . Causes turbidity , cooking utensils , objectionable tastes and colours to
food and drinks .more than 0.2 mg/l is objectionable for most industrial uses.
Manganese (Mn) :- Comes from soils igneous and metamorphic rocks . More than 0.2mg/l
precipitates upon oxidation causes undesirable tastes . Stains plumbing fixtures and laundry
fosters growth in reservoirs , and most industrial users object to water containing more than 0.2
mg/l.

6. • Toatal dissolved solids:- is a measure of the total amount of minerals dissolved in water
and is very useful parameter in the evaluation of water quality. Water containing less
than 500 mg/L is preferred for domestic use and for many industrial processes.
• USGS classification
• <1000-fresh , 1000-3000- slightly saline, 3000-10,000 moderately saline, 10,000-
35,000 very saline and more than 35,000 Briny
• Calcium (Ca):- Ca &Mg combine with bicarbonate,sulfate to form a heat- retarding ,
pipe – clogging scale in boilers and other heat exchange equipment . Originates From
amphiboles, feldspar, gypsum , calcite .
• Generally having concentration less than 100 mg/L and brines contain ≥ 75000 mg/L.
• Magnesium (Mg) :- Ca &Mg combine with ions of fatty acid in soaps to form
soapsuds.

7. • Sodium (Na) & Potassium (K) :- originates from feldspar, clay minerals,halite.
• More than 50 mg/L Na and K in the presence of suspended matter causes foaming.
Accelerate scale formation and corrosion in boilers.
• Na Generally less than 200mg/l but 1000 mg/l in seawater and 25000 mg/l in brines .
• K generally less than 10mg/l as much as 100 mg/l in hot springs and 25000 mg /l in
brines.
• Carbonate (CO3) Bicarbonate (HCO3) :- upon heating bicarbonate is change into
steam carbon dioxide and carbonate ,combines with alkaline earth metal to form scale
of calcium carbonate that retards flow of heat and fluid through pipe walls . water
containing large amounts of bicarbonate and alkalinity is undesirable in many
industries.
• Carbonate & Bicarbonate Less than 10 mg/l & 500 mg/l in G.W. respectively.

8. • Sulphate (SO4) :- Originates from sulphide ores gypsum, anhydrite . Sulfate combines
with calcium to form adherent ,heat retarding scale. more than 250 mg/ l is
objectionable in water in Some industries .
• water containing about 500 mg/l of sulphate tastes bitter & about 1000 mg/l may be
Cathartic.
• Chloride (Cl) :- Chief source is evaporites and commonly less than 10 mg/l and
100mg/l salty taste .
• Excess of 100 mg/l may cause physiological damage and not uses for industries like
textile , paper, manufacturing and synthetic rubber .
• Fluoride :- Originates from amphiboles , apatite , fluorite .
• concentration between 0.6 and 1.7 mg/l in drinking water has a beneficial effect on
structure and resistance to decay of children’s teeth .
• Excess of 1.5 mg/l causes mottled enamel in children’s teeth .

9. • Nitrate (NO3) :- Originates from atmosphere, legumes , plant debris ,
animal excrement .
• Commonly less than 10 mg/l .
• containing large amounts of nitrate is bitter tasting and may cause
physiological distress .
• water from shallow wells containing more than 45 mg/l has been reported
to cause Methemoglobinemia in infants.
• Small amounts of nitrate help reduce cracking of high pressure boiler steel
steel .

10. •THANK YOU
• References:-
• David K.Todd and Larry W.Mays Groundwater hydrology 3rd edition
2005,Willey &sons pp 333-337.
• Image by nayla Hassan Omer ,water quality parameters researchgate
.com