Pollution and its pollutants Presented by Satyam Yadav
What is pollution? Any undesirable change in a physical, chemical or biological characteristic of air, water, and land which is harmful to man through directly or indirectly through his animals, plants, industrial units or raw materials is called pollution. POLLUTANTS: Any material or act on the part of man or nature which leads to pollution is called pollutants.
Types of Pollutants: In terms of eco-system, the pollutants can be classified into two basic groups: (a) Non-degradable Pollutants: These are not broken down the natural processes like action of microbes. Most of these Mutants get accumulated in the environment and also get bio-logically magnified as these move along the food chains in an under composed state. These may also react with other com-pounds in the environment to produce toxins. These can be fur-ther subdivided into two more classes: (i) Waste: e.g glass, plastic, phenolic, aluminum cans eto. (ii) Poisons: e.g. radio-active substances, pesticides, smog gases, heavy metals like mercury, lead and their salts.
(b) Degradable pollutants or Bio-degradable Pollutants: These are natural organic substances which can be decomposed, removed or consumed and thus, reduced to le levels either by natural processes like biological or microbial action or by some engineered systems, like sewage treat-ment plants. The degradable pollutants can be further sub-divided into two categories: (i) Rapidly degradable or non-persistent pollutant: The degradation of these pollutants is a very faster process. For example, the decomposition of sewage and wastes of animals and plants is a faster process. The domestic sewage can be rapidly decomposed by natural processes However, the problems become complicated when the input into environment get exceeded of the decomposi-tion or dispersal capacity. (ii) Slowly degradable or persistent pollutant: The degra-dation of these pollutants is a very slow process. It seems as if the amount of pollutant remains unchanged with time. For example, degradation of synthetic com-pounds and radioactive elements like Iodine 137, Stron-tium 90 or Plutonium 239 takes a longer period of time.
Primary pollutants: The primary pollutants are "directly" emitted from the processes such as fossil fuel consumption, Volcanic eruption, and factories. The major primary pollutants are Oxides of Sulphur, Oxides of Nitrogen, Oxides of Carbon, Particulate Matter, Methane, Ammonia, Chlorofluorocarbons, Toxic metals etc. Secondary pollutants: The secondary pollutants are not emitted directly. The secondary pollutants ts of the atmosphere. Most important secondary level Air Pollutants are Ground Level Ozone, Smog, and POPs (Persistent Organic Pollutants).