2. ❖ ENVIRONMENTAL POLLUTION
❖ Pollution is the abnormal and unfavourable alteration of the
environment,with harmful effects on the life of man and other organisms.
❖ Or it is the undesirable change in the physical,chemical, or biological
characteristics of air, land and water that may adversely affect the life of all
organisms.
❖ Pollution is mostly due to the after effect of human population explosion,
unplanned urbanization, irrational industrialisation, undesirable
environmental alteration, overexploitation of natural resources and intensive
agricultural practices.
3. EFFECTS OF ENVIRONMENTAL POLLUTION
• It abnormally changes the dynamics of the ecosystem and adversely
affects the efficiency and organization of species.
• Poisons the whole biosphere and poses serious threats to the normal life
of organisms.
• It causes unfavourable changes in climate and other environmental
conditions.
• It causes the wastage, qualitative degradation and quantitative depletion
of natural resources.
• Pollution induces serious disorders and diseases and adversely affects
human health and welfare.
4. POLLUTANTS
• Pollutants are the gaseous,solid or liquid substances or agents
which can cause pollution.
• Mostly pollutants are the byproducts of man’s actions.
• In general, pollutants include physical factors, chemical or
geochemical substances, biological organisms and their products.
5. MAJOR POLLUTANTS
• Physical pollutants- Radiations, heat, sound etc.
• Geochemical pollutants- Dust, silt, sediments etc.
• Deposited pollutants- Soot, smoke, tar, dust etc.
• Gaseous pollutants- Oxides of carbon, nitrogen and sulphur, halogens
etc.
• Particulate pollutants- Extremely fine suspended or dispersed solid
particles or liquid droplets. Solid particles include dust, smoke, fumes
etc. Liquid particles include fog, mist, spray etc.
6. • Metallic pollutants- Lead, iron, mercury, zinc, nickel etc.
• Acidic pollutants- Droplets of H2SO4, HCl etc.
• Organic substances- Benzene, ether, acetic acid etc.
• Agrochemicals- Insecticides, pesticides, fungicides etc.
• Industrial wastes and radioactive wastes.
• Photochemical oxidants- Photochemical smoge, Peroxyacyl nitrate ( PAN),
ozone, aldehydes etc.
• Biological pollutants- Living organisms and their eggs, cysts, pollen grains,
fungal spores etc.
• Unwanted noise.
7. PRIMARY AND SECONDARY POLLUTANTS
• Two major groups of environmental pollutants, they are primary and
secondary pollutants.
• Primary pollutants are the simple pollutants, directly released to the
environment from their sources. Eg. CO, NO, H2S, hydrocarbons,
particulate pollutants etc.
• Secondary pollutants are the complex pollutants, formed in the
environment by chemical combination of primary pollutants with other
substances. They are not emitted directly to the environment. Eg.
Peroxyacyl nitrate formed by the combination of nitrogen oxides with
hydrocarbons, ozone, atmospheric acids etc.
8. QUALITATIVE AND QUANTITATIVE
POLLUTANTS
• Based on natural existence, pollutants may be classified in to two groups
namely qualitative and quantitative.
• Qualitative pollutants are the pollutants which do not normally occur in the
environment, but are introduced into the environment by human activity. Eg.
Fungicides, pesticides, insecticides etc.
• Quantitative pollutants are the substances which turn to be pollutants when
their environmental concentration exceeds a threshold value. Eg. Nitrogen
oxides, CO, CO2, etc.
9. BIODEGRADABLE AND NON-DEGRADABLE
POLLUTANTS
• Two groups of chemical pollutants namely bio-degradable and non-
degradable.
• Degradable pollutants decompose easily and suddenly by microbial or
chemical action under normal natural conditios. So they get easily re-cycled in
the ecosystem. Eg. Domestic sewage, sulphates, carbonates etc.
• Non-degradable pollutants are highly persistent and they will not usually
decompose, or decompose very slowly, under normal natural conditions. So,
they are accumulate in the ecosystem and get progressively more and more
concentrated from lower to higher trophic levels. This is called biological
magnification. Eg. Plastics, rubber, heavy metal particles, chlorinated
hydrocarbons like DDT,BHC etc.
