ENVIRONMENTAL POLLUTION Pollution is the introduction of contaminants

ENVIRONMENTAL POLLUTION

Pollution is the introduction of contaminants into an environment that causes instability, disorder, harm or discomfort to the ecosystem

Types of pollution Air pollution Water pollution Land pollution Noise pollution Thermal pollution Marine pollution Nuclear hazards

AIR POLLUTION Air pollution is the presence of contaminants in atmosphere in quantities such that it is injurious to human, plant animal life and property The main pollutants in the atmosphere are SO 2 (sulphur dioxide), CO (carbon monoxide), oxides of nitrogen, carbon dioxide and lead.

Sulphur dioxide: Sources: Combustion of fossil fuels. coal and crude oil contain up to 3% sulphur. Roasting of ores. sulphide ores on roasting, are converted to sulphur trioxide. This, when let into the atmosphere, combines with the moisture in the atmosphere to form sulphuric acid. e. g roasting of galena , the sulphide ore of lead 2 Pb. S + 3 O 2 ---- 2 Pb. O + 2 SO 2 + O 2 ----- 2 SO 3 H 2 O + SO 3 ---- H 2 SO 4

Volcanic eruptions also emits sulphur dioxide. Effects of SO 2: Sulphur dioxide pollution in the atmosphere affects causes the following damages : In humans : it causes eye irritation, cough, lung diseases including lung cancer and asthma In plants: it causes damage of leaves, bleaching of chlorophyll which turns leaves brown, damage to crops and to growth of plants.

Control: The gases evolved during combustion of fossil fuels are passed through calcium carbonate when SO 2 is converted to calcium sulphite. Ca. CO 3 + SO 2 ---- Ca. SO 3 + CO 2 lime is added to coal and roasted at high temperature so that Ca. O formed combines with SO 2 to form calcium sulphate. Ca. O + SO 2 + ½ O 2 ------ Ca. SO 4

Carbon monoxide Sources: Oxidation of methane releases carbon monoxide into the atmosphere. Automobile exhaust- carbon monoxide is formed during the combustion of fuel such as petrol. Industries: carbon monoxide is released by industries such as iron and steel and petroleum. CO 2 + C ------- 2 CO 2 ----- 2 CO + O 2

effects When the atmosphere is polluted with carbon monoxide, on inhalation, CO combines with the hemoglobin to form car boxy hemoglobin and hence oxygen carrying capacity of the blood decreases. This causes, headache, dizziness, unconsciousness. When inhaled for a long duration it may cause even death. Control: Using catalytic converter in automobiles

Oxides of nitrogen (NOx) Nitric oxide, nitrogen dioxide and nitrous oxide are three main oxides of nitrogen found in the atmosphere Sources: The sources for the oxides of nitrogen are: Bacterial decomposition of nitrogenous compounds Combustion during lightning, oxygen and nitrogen in the atmosphere combine to give oxides of nitrogen. industries and automobile exhaust - Air is sucked into the IC engines. At high temperatures, nitrogen and oxygen in the air combine to form nitric oxide.

effects: The oxides of nitrogen combine with moisture in the atmosphere to form nitrous and nitric acid. This leads to increase in the acidity of rain water. Formation of photochemical smog: oxides of nitrogen combine with hydrocarbons present in the atmosphere forming peroxyacyl nitrate. Control: Using catalytic converter in automobiles, Catalytic converters use Pt/ Rh catalyst. the presence of these catalysts, the oxides of nitrogen are converted to nitrogen and oxygen. 2 NOx ---- N 2 + x O 2

Lead pollutant Sources: The exhaust from automobiles which use lead tetraethyl as antiknocking agent. Paint pigments : Litharge and red lead ( oxides of lead ) and lead chromate are used as pigments. These cause lead pollution

effects: Lead competes with calcium and enters the blood and bone marrow. The lead interferes in the manufacture of red blood corpuscles and abnormal multiplication of blood cells and thus leads to anaemia and blood cancer in human beings. Lead enters the blood and various organs of the body including the brain and the Kidneys leading to dysfunction of the kidney and damage to the brain.

WATER POLLUTION Any alteration in physical, chemical or biological properties of water, as well as the addition of any foreign substance makes it unfit for health and which decreases the utility of water, is known as water pollution.

Main sources of water pollution are: (i) domestic and municipal sewage (ii) industrial waste (iii) agricultural waste (iv) radioactive materials, etc. , POINT AND NONPOINT SOURCES Two types of water pollutants exist; point source and nonpoint source. Point sources of pollution occur when harmful substances are emitted directly into a body of water. e. g. , Oil spill A non-point source delivers pollutants indirectly through environmental changes. . eg. , fertilizer from a field is carried into a stream by rain

Point Sources

Non Point Sources

Classes of pollution, pollutants n Pathogens, parasites n Oxygen-demanding wastes n Inorganic chemicals n Inorganic plant nutrients n Organic chemicals n Sediments n Radioactive material n Heat (thermal pollution)

Pathogens, parasites n n n Usually from sewage, feedlots, slaughterhouses Viruses Bacteria (cholera, . . . ) Coliform bacteria usually not pathogenic, Used as indicators of pollution n Protozoan parasites (Giardia, Cryptosporidium) Oxygen-demanding wastes n n Organic materials from sewage, slaughterhouses, etc. Decomposed by bacteria Bacteria require, consume dissolved oxygen n “Biological Oxygen Demand” (BOD) Measure of water quality Low in pristine water

Inorganic chemicals n n Mostly from industry Heavy metals Lead, arsenic, mercury, copper ions, etc. n n Ammonia Acids Sulfuric acid, nitric acid from acid deposition Also from industry n Bases (caustic alkalines) Inorganic plant nutrients (fertilizers) n From agriculture, lawns & gardens Leaching into groundwater Run-off into surface waters n Stimulate growth of algae (algal blooms), eutrophication Algae die, sink, become oxygen-demanding waste

Organic chemicals n n n from industry, restaurants, cars, households, farms Gasoline, oil Engine coolant (ethylene glycol) Solvents Detergents Pesticides insecticides, herbicides, fungicides n Polychlorinated Biphenyls (PCBs)

Sediments n n Erosion from construction sites, streets & roads, farms, sewage Dense sediments sink, accumulate Sedimentation in reservoirs n Less dense sediments may stay in water Reduce clarity (increase turbidity) Reduce light penetration & photosynthesis

Sewage treatment In primary treatment, the suspended solids and floating objects are removed using coarse screens and sieves. In secondary treatment, the maximum proportions of the suspended inorganic/ organic solids are removed from the liquid sewage. The liquid material passes into the sedimentation tank and finely suspended particles are allowed to settle by adding coagulants like Alum.

Tertiary treatment Remove detergents, metal ions, nitrates and pesticides, as these are not removed in the earlier treatments. The phosphates are removed as calcium phosphates by adding calcium hydroxide at p. H 10 -11. At this p. H, ammonium salts are also converted into ammonia. T The effluent is chlorinated to remove pathogenic bacteria's and finally passed through activated charcoal to absorb gases.

NOISE POLLUTION Noise Pollution can be defied as unwanted or offensive sounds that unreasonably intrude in to our daily activities The various sources of noises are associated with urban development; road-air and rail transport; Industrial noise. In our country, indiscriminate use of loud speakers, generator sets and firecrackers has given new dimensions to the noise pollution problem

The commonly used parameter for noise is the sound level in decibels (d. B). Human ears are sensitive in the frequency range of 20 Hz to 20 k. Hz Effects Noise can disturb out work, rest, sleep and communication. It can damage our hearing and evoke other psychological, physiological and possibly pathological reactions.

Sound Source Sound Level d. B Subjective Feeling of Human Beings Rockets and missiles, heavy explosives 160 Unbearable Jet Planes and cannons, explosives 140 Unbearable Aircraft Propeller and Machine Guns 130 Unbearable Diesel, steam engine and ball mills, crackers 120 Unbearable Electric saws and looms, heavy trucks 110 Unbearable

Major Noise Sources: 1. Road Traffic: Road traffic noise is one of the most widespread and growing environmental problems in urban area. The impact of road traffic noise on the community depends an various factors such as road location and design, land use planning measures, building design, Vehicle standards and deriver behavior. Motor vehicle ownership in India has increased substantially over the last 30 years and general levels of road traffic noise throughout India have increased through out the period.

2. Air Traffic: The extend of aircraft noise impact depends on the type of aircraft flown, the number of flights and flight paths. The increase in number of flights, an important factor is overall noise levels, the led to an increase in general noise levels associated with air traffic. 3. Rail Traffic: The two main sources of noise and vibration relating to the operation of the rail network is 1. The operation of trains and the maintenance 2. Construction of rail infrastructure.

Neighborhood & Domestic Noise: Other significant source of noise annoyance is car alarms, building construction and household noise.

THERMAL POLLUTION Energy is the basic necessity for the economic development of a country. Energy exists in different forms. Also, it can be converted from one form to another form. The electrical energy is produced in power plants or generating stations. The conventional power plants are:

1. Steam or Thermal Power station 2. Hydro-electric Power station, 3. Nuclear Power station

Steam or Thermal Power station In thermal power station, the steam is produced in the boiler, using the heat released by the combustion of coal, oil or natural gas. The steam is used to rotate the steam turbine (impulse/ reaction). The steam turbine drives the alternator, which converts mechanical energy into electrical energy

Hydro-electric Power station Hydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy. Once a hydroelectric complex is constructed, the project produces no direct waste, and has a considerably lower output level of the greenhouse gas carbon dioxide (CO 2) than fossil fuel powered energy plants

Nuclear Power station Nuclear power is produced by controlled (i. e. , non-explosive) nuclear reactions. Commercial and utility plants currently use nuclear fission reactions to heat water to produce steam, which is then used to generate electricity.

Ecological effects Elevated temperature typically decreases the level of dissolved oxygen (DO) in water. Thermal pollution may also increase the metabolic rate of aquatic animals. A large increase in temperature can lead to the denaturing of life.

Control of thermal pollution Thermal pollution from industrial sources is generated mostly by power plants, petroleum refineries, pulp and paper mills, chemical plants, steel mills and smelters. • cooling ponds, man-made bodies of water designed for cooling by evaporation, convection, and radiation cooling towers, which transfer waste heat to the atmosphere through evaporation and/or heat transfer cogeneration, a process where waste heat is recycled for domestic and/or industrial heating purposes.

SOIL POLLUTION

soil pollution is caused by the presence of human-made chemicals or other alteration in the natural soil environment.

This type of contamination typically arises from application of pesticides, percolation of contaminated surface water to subsurface strata, oil and fuel dumping discharge of industrial wastes to the soil. The most common chemicals involved are petroleum hydrocarbons, solvents, pesticides, lead and other heavy metals.

Health effects Chronic exposure to chromium, lead and other metals, petroleum, solvents, and many pesticide and herbicide formulations can be carcinogenic. Chronic exposure to benzene leads to leukemia. Mercury and cyclodienes are known to induce higher incidences of kidney damage.

Ecosystem effects soil contaminants can have significant deleterious consequences for ecosystems Effects occur to agricultural lands which have certain types of soil contamination alteration of metabolism of endemic microorganisms.

SOLID WASTE MANAGEMENT Each household generates garbage or waste day in and day out. There are different types of solid waste depending on their source

Types of solid waste Solid waste can be classified into different types depending on their source: Household waste is generally classified as municipal waste Industrial waste as hazardous waste Biomedical waste or hospital waste as infectious waste

Municipal solid waste consists of household waste, construction and demolition debris, sanitation residue, and waste from streets. This garbage is generated mainly from residential and commercial complexes.

Hazardous waste Industrial waste is considered hazardous as they may contain toxic substances. Certain types of household waste are also hazardous. Hazardous wastes could be highly toxic to humans, animals, and plants; are corrosive, highly inflammable, or explosive; and react when exposed to certain things e. g. gases.

Hospital waste is generated during the diagnosis, treatment, or immunization of human beings or animals or in research activities in these fields or in the production or testing of biological samples. It may include wastes like sharps, soiled waste, disposables, anatomical waste, cultures, discarded medicines, chemical wastes, etc. These are in the form of disposable syringes, swabs, bandages and body fluids.

Recycling and reuse Recycling involves the collection of used and discarded materials processing these materials and making them into new products. It reduces the amount of waste that is thrown into the community dustbins thereby making the environment cleaner and the air more fresh to breathe.

RADIO ACTIVE POLLUTION the uncontrolled distribution of radioactive material in a given environment Radioactive contamination is typically the result of a spill or accident during the production or use of radionuclide (radioisotopes), an unstable nucleus which has excessive energy. Contamination may occur from radioactive gases, liquids or particles

Radioactive contamination can enter the body through ingestion, inhalation, absorption, or injection. For this reason, it is important to use personal protective equipment when working with radioactive materials.

The radioactive pollution can be controlled by number of ways. It includes the stoppage of leakage from the radioactive materials including the nuclear reactors, industries and laboratories. The disposal of radioactive material must be safe and secure. The protective garments must be worn by the workers who work in the nuclear plants. The natural radiation must be at the permissible limits and they must not cross it.