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SAI INTERNATIONAL SCHOOL
                                                      CLASS-VII

                                            SUBJECT - CHEMISTRY
                                TOPIC- MANAGEMENT OF WASTE WATER
                             SUB TOPIC- SOURCES OF WATER P0LLUTION



                                                  LESSON NOTE

               Sources of water Pollution:-



















                     Industrial waste:-Industries cause water pollution as they release their liquid
                       waste especially chemicals (effluent) into water bodies. These contain harmful
                       chemical like mercury, lead, sulphur, cadmium etc which can affect the
                       nervous system and cause skin infections.
                     Mining Activities: - Mining activates release several harmful metals and
                       other toxic substances which mixed up with water and contaminated it.
                       Accidental oil leakage: - Oil spill a huge concerns large amount of oil
                       enters into the sea and cause problem to aquatic plants and animals.
                     Chemical fertilizers and pesticides: - Excessive use of chemical fertilizers,
                       insecticides, pesticides etc. in agricultural field pollute the ground water. This
                       nutrient rich water promotes the growth of weeds resulting eutrophication.
                       This is a condition leading to depletion of oxygen in water bodies.

                     Leakage from sewer lines: - Leakage from sewer lines can contaminate the
                       underground water.

                     Leakage from Landfills: -   Landfills are huge piles of garbage. When its rain
                       the landfills may leak and pollute the underground water.

                     Domestic waste: -The waste products from homes like human excreta, food
                       waste, plastic wrappers, soaps and detergents etc are known as domestic
                       waste.



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