Water pollution Presented by Satyam yadav
What is water pollution??? Water pollution is caused by addition of organic and inorganic chemicals as well as the biological materials which change the physics and chemical properties of water. This harmful process is called water pollution. The water also caused by many sources such as sewage matter,industrial wastage, agricutural wastage,domestic wastage,hot thermal plant and nuclear reactors etc. NOTE: A 0.1 % impurities makes domestic sewage unfit for human.
Water hyacinth (eichhornia crassipes) the world most problematic aquatic weed also called terror of bengal. -unlike domestic sewage waste water from industries like petroleum ,paper manufacturing,metal extract and processing paper manufacturing,metal extraction and processing,chemical manufacturing,etc.,often contain toxic substance,notably heavy metals(defined as elements worh density>5gm/cm3 such as mercury ,cadmium,copper,lead etc.) and a variety of organic compounds -water having D.O> content below 8 mg/l may be c below 4 mg/l is heavily polluted. -D.O. is measured by oximeter.
1. Biological Oxygen Demand (B.O.D): The water pollution by organic waste is measured in terms ofB.O.D.it s amount of dissolved oxygen needed by bacteria in decomposing the organic waste present in water. B.O.D increased- water polluted If B.O.D is increased dissolved oxygen is decreased in water.higher amount of organic waste the rate of decomposition in water. Oxygen is rapidly consumed by microbes ,thereby causing by drop in D.O. content in water. Note- Daphnia is the indicator of B.O.D. 2. Chemical oxygen demand It is the oxygen requirement by chemical for oxidation of total organic matter(biodegradable+non biodegradable) in water.
Note: C.O.D. value is always higher than B.O.D. values. 3. Biological magnification The non biodegradable pollutant like Al,Hg,Fe,DDT,pesticides,phenolic compounds ABS (alkyl benzone sulphonate) are not decomposed by micro organisms. They get accumulated in tissue in increasing concentration along the food chain is called biological magnification.the high conc occurs in top consumer. 4 Eutrophication : The process of nutrient enrichment of water and consequent loss of species biodiversity is referred to as eutrophication and lake is known as eutrophic lake.i this process presence of nutrients in lake stimulates growth of algae increase organic loading and bring about reduction in the oxygen content of water causing death of aquatic animals.
NOTE: During eutrophication due to organic matter lake become shallow and warmer.Due to warming of lake water ,growth of cold water organisms stop and growth of warm water organisms increase. B.O.D. of eutrophication lake is very high. TYPES OF LAKES a) Eutrophic lake-they are shallow water lacks which contain high amount of organic materials and nutrients. They have little oxygen because decomposers rapidly use it up. Chironomous larva are commonly present in it. E.g. Dal lake of Kashmir b)Oligotrophic lake- These are deep lakes which have less amount of organic material and nutrients.
Eutrophication can be caused by following man made source: a)house holds b)industrial waste c) sewage
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