WATERHOLIC – A DROP OF WATER , A DROP OF
ESPERINO GENIKO LYKEIO LAMIAS
SCIENTIFIC FACTS OF WATER
• A colorless, odorless, tasteless liquid, water is the only
common substance that occurs naturally on the earth in all
three states : solid, liquid and gas.
• Approximately 73% the earth’s surface, almost 328 million
cubic miles, is covered with water.
• The human body is 70% water by weight and water is
essential to the life of every living thing.
THE WATER MOLECULE STRUCTURE
• Water is the most abundant molecule on Earth’s surface. It’s a
chemical compound with the chemical formula H2O and
consists of two atoms of hydrogen bonded to one atom of
oxygen. The bonds which hold the hydrogen and oxygen
atoms together are called covalent bonds. The water
molecule forms an angle (104.3 degrees),with hydrogen
atoms at the tips and oxygen at the vertex.
• An important feature of water is its polar nature. The side
with the hydrogen atoms which has a positive charge attracts
the oxygen side which has a negative charge. This charge
difference is called a dipole. Since opposite electrical charges
attract each other these charge differences cause water
molecules to be attracted to each other and to other polar
molecules. This attraction contributes to hydrogen bonding
and explains many of the amazing properties of water.
UNIQUE PROPERTIES OF WATER
• Water is called universal solvent because it is capable of
dissolving a variety of different substances, in fact more
substances than any other liquid. This is important to every
living thing on Earth. It means that wherever water goes
either through the air, ground or our bodies it takes along
chemicals, minerals and nutrients.
• Cohesion when water molecules are attracted to water
molecules and adhesion when water molecules are attracted
to molecules of other substances.
• High surface tension shows that water is sticky and elastic
and tends to clump together in drops rather than spread out.
Surface tension is responsible for capillary action.
• High heat capacity means that it can absorb a lot of heat
before it begins to get hot.
• Changes in density based on temperature. Water freezes at 00
C and boils at 1000 C. The solid form of water, ice is less dense
than the liquid form which is why ice floats.
WATER QUALITY PROPERTIES
• PH is the value that determines if water is acidic, neutral or
basic. It is measured on a scale from 0 to 14 on which 7 means
water is neutral. PH values less than 7 indicate that water is
acidic and pH values more than 7 indicate that it is basic. It is
a measure of the relative amount of free hydrogen and
hydroxyl ions in the water. Since pH can be affected by
chemicals in the water it is an important indicator of water
that is changing chemically. Water with a pH of 5 is ten times
more acidic than water having a pH of 6. Pollution can change
water’s pH, which in turn can harm animals and plants living
in the water. Pure water is neither acidic nor basic.
• Turbidity is a measure of non - transparency of water due to
the presence of suspended materials that scatter light passing
through the water.
• Conductivity is the ability of water to conduct electrical
current. It is dependent on the amount of dissolved solids.
Distilled water has lower conductivity than sea water.
• Alkalinity is the amount of buffering material in the water to
neutralise an acid or a base , so that the pH of the water will
• Hardness indicates the excessive amount of dissolved
minerals, such as calcium and magnesium in water.
• Dissolved oxygen is a measure of how much oxygen is
dissolved in water. Although water molecules contain an
oxygen atom, this oxygen is not what is needed by aquatic
organisms to breathe and survive.
• Water temperature affects the feeding, reproduction and
metabolism of aquatic species. Temperature also can affect
dissolved oxygen levels as well as the ability of organisms to
resist certain pollutants.
• Water color blue :transparent water with a low accumulation
of dissolved materials, yellow or brown: dissolved organic
materials, humic substances from soil ,peat or decaying plant
material, red: can be produced by some algae, green: water
rich in phytoplangton and other algae, a variety of yellow, red,
brown and grey colors: may be caused by soil runoff.
• Odor sewage and industrial waste or decomposing vegetation
and microbial activity can cause odor although water is
• Suspended sediment is the amount of soil in water. During
rain storms, soil is washed away and the amount depends on
the type of land and the vegetation surrounding the water.
Excess sediment can harm the water quality.
• Nitrates - Nitrogen are essential for plant growth but
excessive amounts in water supplies presents a major
pollution problem. They may enter water from agricultural
fertilizers, human sewage, industrial wastes, livestock wastes
and farm manure.
• Phosphates are applied as fertilizer to agricultural fields, grass
lawns and golf courses. Phosphates can accelerate the
growth of algae and aquatic plants and therefore cause
• Carbon Dioxide in water is necessary for aquatic organism
growth and respiration. CO2 increases when organic wastes
reduce the oxygen available for these organisms.
• Iron in water may stain fixtures and may have an odor or
taste. High values in water may indicate contamination from
• Fresh water is water which occurs on Earth’s surface (lakes,
streams, rivers) and underground, containing minimal
quantities of dissolved salts.
• Bottled water is drinking water packaged in plastic or glass
bottles and it can be carbonated or not.
• Mineral water comes from mineral springs and contains
amounts of dissolved minerals and salts (calcium, sodium,
magnesium, iron) and sulfur compounds.
• Carbonated water is water in which carbon dioxide gas under
pressure has been dissolved. It is the major ingredient of
carbonated soft drinks.
• Purified water is mechanically filtered and processed to be
cleaned for usage. Most common forms are distilled and
deionized water used in science, industries and engineering
• Hard water is water with large concentrations of alkaline salts
such as calcium and magnesium.
• Soft water does not contain large concentrations of calcium
• Heavy water is water in which both H atoms have been
replaced with deuterium , the isotope of hydrogen containing
one proton and one neutron.
• Brackish water is mixed fresh and salt water due to salt water
intrusion into coastal water wells.
• Saline water or salt water contains significant amounts of
dissolved salts, most common of all sodium chlorine (NaCl).
Desalination is the removal of salts from saline water to
produce fresh water.
Water pollution is the contamination of water bodies such as
lakes, rivers, oceans and groundwater caused by activities of
people and can be harmful to organisms and plants which live
in the water and human beings as well.
The water pollutants can be organic and inorganic.
ORGANIC WATER POLLUTANTS INCLUDE
• Disinfection by-products found in chemical disinfected
drinking water such as chloroform
• Food processing waste which include oxygen demanding
substances, fats and grease
• Insecticides, herbicides, a huge range of organohalides and
other chemical compounds
• Petroleum hydrocarbons, including fuels, lubricants and fuel
combustion by products from stormwater runoff
• Tree and bush debris from logging operations
• Volatile organic compounds (VOCs) such as industrial solvents
from improper use
• Chlorinated solvents which are dense non-aqueous phase
• Various chemical compounds found in personal hygiene and
• Drug pollution involving pharmaceutical drugs and their
INORGANIC WATER POLLUTANTS INCLUDE
• Acidity caused by industrial discharges (especially sulfur
dioxide from power plants)
• Ammonia from food processing waste
• Chemical waste as industrial by-products
• Fertilizers containing nutrients, nitrates and phosphates,
which are found in stormwater runoff from agriculture as well
as commercial and residential use
• Heavy metals from motors vehicles and acid mine drainage
• Silt runoff from construction sites, logging, slash and burn
techniques or land cleaning sites.