3. introduction
Environmental Chemistry deals with the origins,
transport, reactions, effects and fates of chemical
species in the water, air, terrestrial and living
environments.
It overlaps with different branches of chemistry such
as organic chemistry, analytical chemistry, physical
chemistry, photochemistry, geochemistry and
biological chemistry and also includes many widely
different fields such as physics, life sciences,
agricultural sciences, medical sciences, public health
and sanitary engineering.
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5. ENVIRONMENTAL STUDIES deals with the sum of
all social ,economical ,biological ,physical &chemical
interrelations with our surroundings.
ENVIRONMENTAL CHEMISTRY deals with the study
of the origin , transport ,reactions ,effects ,and fates of
chemical species in the environment
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7. AIR POLLUTION
Air pollution occurs due to the presence of
undesirable solid or gaseous particles in the air. The
following are the major gaseous and particulate
pollutants present in the troposphere:
1.Gaseous air pollutants: These are oxides of Sulphur,
oxides of nitrogen, hydrocarbons, ozone and other
oxidants.
2.Particulate pollutants: These are dust, mist, fumes,
smoke, smog etc.
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9. The decrease of ozone in middle layers of atmosphere
mainly in the stratosphere is extremely damaging the
life on earth and is largely caused by emissions of
halogenated hydrocarbons produced by man e.g
CFCs, HCFCs, hallon's, CCl4, CH3Br.
Ozone destruction mechanism:-
Substances such as CFCs and others that are cited,
that lowers the ozone layer don't directly destroy
ozone.
10. First they undergo photolysis, forming HCl or
ClONO2, molecules which don't react ozone directly,
but slowly decompose giving, among other things, a
small no. Of chlorine atoms and of chlorine monoxide
molecules that catalyse the destruction of ozone the
reactions involved in the process of destruction are
11. More that hundred, one of the reaction is as under:
Cl + O3 ClO +O2
ClO + O Cl + O2
Net reaction:
O3 + O 2 O2
The chlorine atom acts as a catalyst i.e it is not
consumed in the reaction, so it destroys thousands of
ozone molecules before disappearing.
12. Causes:
CFCs :- These are the compounds formed by
flourine, chlorine and carbon they are often used as
refregirents, solvents, and for the manufacture of
spongy plastics. CFCs: The chemicals used as
propellent for aerosol cans and bromo-flouro carbons,
halones, are destroying the earth's ozone layer. These
chemicals where used in freon and for fighting fires.
Manufacturers thought that the chemicals were inert
and not harmful to the environment.
13. When the chemicals reach to the earth's stratosphere
they reacted with ultra violet radiation which caused
them to breakdown and release chlorine and bromine
into earth's ozone layer. The ozone layer protects the
earth from UV rays. The chemicals causing the
chemical reaction, which made the ozone layer to
breakdown Into a pure oxygen. The layer lost its
shielding effect from the sun's UV rays. The bromine
and chlorine kept interacting with the ozone
molecule untill they eventually left the ozone layer to
bond with other compounds.
14. ACID RAIN
We are aware that normally rain water has a pH of 5.6
due to presence of Hydrogen ions formed by reaction
of rain water with carbon dioxide present in the
atmosphere.
When the pH of the rain water drops below 5.6, it is
called acid rain. Oxides of Sulphur and nitrogen in the
atmosphere produces acid rain.
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16. Water pollution
Water pollution is the contamination of water bodies .
Water pollution occurs when pollutants are discharged
directly or indirectly into water bodies without adequate
treatment to remove harmful compounds Main causes of
water pollution are pathogens , organic waste and
chemical pollutants.
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17. SOIL POLLUTION
Soil contamination or soil pollution is caused by the
presence of human-made chemicals or other
alteration in the natural soil environment. It is
typically caused by industrial activity, agricultural
chemicals, or improper disposal of waste. Main causes
of soil pollution are pesticides and industrial waste.
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18. RADIOACTIVE POLLUTION
Radioactive pollution can be defined as the emission
of high energy particles or radioactive substances into
air , water or land due to human activities in the form
of radioactive waste.
Radioactive rays can cause irreparable damage to
DNA molecules and can lead to life.
threatening condition.
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19. EFFECTS OF POLLUTION
Disrupts ecosystems Damages the environment
Causes mutations (nuclear or radio active pollution )
Causes human health implications Global warming
Species extinction Loss of biodiversity.
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