ENVIRONMENTAL POLLUTION ENVR-252 CHAPTER # 2

Transcription

1 ENVIRONMENTAL POLLUTION ENVR-252 CHAPTER # 2 POLLUTION Pollution - addition of undesirable material into the environment as a result of human activities. The agents which cause environmental pollution are called pollutants. Pollutants - A physical, chemical or biological substance unintentionally released into the environment which is directly or indirectly harmful to humans and other living organisms. 1

2 TYPES OF POLLUTION 1. Soil pollution 2. Noise pollution 3. Water pollution 4. Air pollution 5. Thermal pollution 6. Radiation pollution 7. Light Pollution TYPES OF POLLUTION Soil Pollution 2

3 SOIL POLLUTION Addition of substances which adversely affect the quality of soil or its fertility is known as soil pollution. SOURCES OF SOIL POLLUTION 1. Agricultural Sources 2. Industrial sources 3. urban activities 3

4 1. AGRICULTURAL SOURCES Agricultural chemicals especially fertilizers and pesticides pollute the soil. The remnants of such pesticides may get adsorbed by the soil particles and contaminate root crops grown in that soil. Pesticides are highly toxic chemicals which affect humans and other animals adversely causing respiratory problems, cancer and death. AGRICULTURAL EFFECTS: 4

5 2. INDUSTRIAL SOIL POLLUTION Large quantity of solid wastes like unused and rejected chemicals (like sludge, bottles, plastic materials etc.), unwanted industrial wastes generated during manufacturing processes are dumped over on the surface of soil by almost all industries with difference in the degree. INDUSTRIAL EFFECTS: Soil pollution due to industrial waste Polluted land with dangerous chemicals 5

6 3. SOIL POLLUTION DUE TO URBANIZATION Urban activities generate large quantities of city wastes including several Biodegradable materials (like vegetables, animal wastes, papers, wooden pieces, plant twigs, leaves, cloth wastes as well as sweepings) and many non-biodegradable materials (such as plastic bags, plastic bottles, plastic wastes, glass bottles, glass pieces, stone / cement pieces). URBANIZATION EFFECTS: 6

7 METHODS TO CONTROL SOIL POLLUTION Reducing - chemical fertilizer and pesticide & use manure as a by-product. Recycling - another way to reduce and control soil pollution. Recycling paper, plastics and other materials reduces the volume of waste in landfills. Reforestation- the cutting down of trees, causes erosion, pollution and the loss of fertility in the topsoil. Planting trees-- or re-forestation--helps prevent soil erosion and pollution. Bioremediation- Use of microorganisms and plant to breakdown contaminants and remediate soil pollution. METHODS TO CONTROL SOIL POLLUTION 7

8 NOISE POLLUTION Noise - A sound without value or any noise that is unwanted by the recipient. Noise level - measured in terms of decibels (db). WHO (World Health Organization) has prescribed optimum noise level as 45 db by day and 35 db by night. Anything above 80 db is hazardous. SOURCES OF NOISE POLLUTION Indoor sources - noise produced by radio, television, generators, electric fans, air coolers, air conditioners, different home appliances, and family conflict. Outdoor sources - indiscriminate use of loudspeakers, industrial activities, automobiles, rail traffic, airplanes and activities such as those at market place, religious, social, and cultural functions, sports and political rallies. 8

9 EFFECTS OF NOISE POLLUTION Noise disturbs sleep, causes hypertension (high blood pressure), emotional problems such as aggression, mental depression and annoyance. CONTROL OF NOISE POLLUTION Road traffic noise reduction- better designing and proper maintenance of vehicles. Noise abatement measures - creating sound proof walls, better designing and proper maintenance of vehicles 9

10 CONTROL OF NOISE POLLUTION Industrial noises - reduced by sound proofing equipment like generators and areas producing lot of noise. Very loud music and public functions using loudspeakers, Use of fire crackers which are noisy and cause air pollution etc. should not be permitted at night. CONTROL OF NOISE POLLUTION A green belt of trees is an efficient noise absorber. 10

11 WATER POLLUTION Water pollution is the addition of undesirable substances in water bodies. Types: Surface water, e.g. Lakes, rivers, oceans Ground water, e.g. aquifers Water pollution occurs when pollutants are discharged in water bodies without adequate treatment to remove harmful compounds. SOURCES OF WATER POLLUTION NONPOINT SOURCES Rural homes Urban streets Cropland Animal feedlot Suburban development POINT SOURCES Factory Wastewater treatment plant 11

12 POLLUTION DUE TO PESTICIDES AND INORGANIC CHEMICALS Pesticides like DDT and others used in agriculture may contaminate water bodies. Aquatic organisms take up pesticides from water, get into the food chain (aquatic in this case) and move up the food chain. At higher trophic level they get concentrated and may reach the upper end of the food chain. INDUSTRIES Metals like lead, zinc, arsenic, copper, mercury and cadmium in industrial waste waters adversely affect aquatic organisms and other animals. Oil pollution of sea occurs from leakage from ships and oil tankers. Accidents of oil tankers spill large quantity of oil in seas which kills marine birds and adversely affects other marine life. Incident of Exxon Valdez Oil Spill 12

13 THERMAL POLLUTION Power plants- thermal and nuclear, chemical and other industries use lot of water for cooling purposes and the used hot water is discharged into rivers, streams or oceans. Increase in water temperature decreases dissolved oxygen in water which adversely affects aquatic life (plants and animals). One of the best methods of reducing thermal pollution is to store the hot water in cooling ponds, allow the water to cool before releasing into any receiving water body EFFECTS OF WATER POLLUTION 13

14 1. EUTROPHICATION Discharge of domestic waste, agricultural surface runoff and industrial effluents in a water body leads to rapid nutrients enrichment in a water body. The excessive nutrient enrichment in a water body encourages the growth of algae. The biological demand for oxygen (BOD) increases with the increase in aquatic organisms. 2. DISEASES Consumption of arsenic polluted water leads to accumulation of arsenic in the body parts like blood, nails and hairs causing skin lesions, rough skin, dry and thickening of skin and ultimately skin cancer. Pollution of water bodies by mercury causes Minamata disease in humans and dropsy in fishes. 14

15 2. DISEASES Water pollution is the major source of water born diseases. e.g. B o Bacterial Diseases: Cholera, Dysentery, Typhoid fever. o o Viral Diseases: Hepatitis A Protozoan Diseases: Amoebiasis CONTROL OF WATER POLLUTION 1. The sewage water can be treated to make it safe for disposal into water bodies like rivers, lakes etc. 2. The treatment involves three stages: primary treatment, secondary treatment and tertiary treatment. 3. This treatment of waste water or sewage is carried out in wastewater treatment plants especially built for this purpose. 15

16 CONTROL OF WATER POLLUTION The treatment involves three stages: 1. Primary treatment: Large particles are removed in this stage (Plastic bags, stones, clothes, wood pieces) 2. secondary treatment : removes organic solids by microbial decomposition. 3. Tertiary treatment: Removes nutrients and pathogens from water. CONTROL OF WATER POLLUTION The following measures can be adopted to control water pollution: (a) The water requirement should be minimized by altering the techniques involved. (b) Water should be reused with or without treatment. (c) Recycling of water after treatment should be practiced to the maximum extent possible. (d) The quantity of waste water discharge should be minimized. 16

17 RECYCLING OF WATER Recycling refers to the use of wastewater by the original user prior to the discharge either to a treatment system or to a receiving water body. Thus the waste water is recovered and repetitively recycled with or without treatment by the same user. 17