Unit – 3

Environmental Chemistry And Pollution Control

3.1           Chemistry of Environment

Green Technology

Principles of Green technology, Zero Waste Technology, Green Chemistry & Its basic principles, Atom Economy, Green Methodologies. Clean development mechanisms (CDM), concept of environmental impact assessment

Principles of Green technology

It is a technology which is environmentally friendly, developed and used in such a way so that it doesn’t disturb our environment and conserves natural resources.

“Green Technology” is a system that uses innovative methods to create environmental friendly products It uses renewable natural resources that never depletes, so future generation can also benefit from it. It can effectively change waste pattern and production in a way that it won’t harm the planet.

Zero Waste Technology

Generally, “Zero Waste” is a philosophy of eliminating the generation of materials that have no viable or economic option for end-of-use management. In reality, there are varying interpretations for when (and if) it is achieved.

The generation of waste can be lowered through a variety of options, including reducing, reusing, recycling, or taking appropriate action to prevent waste through design and engineering solutions. Many individuals, companies and municipalities continue to strive to achieve zero waste goals, while our very own Waste Management Phoenix Open is the largest zero waste event of its kind in the world.

Green Chemistry & Its basic principles

• Prevent waste.
• Less hazardous chemical synthesis.
• Safer chemicals and products.
• Safer solvents and reaction conditions.
• Increase energy efficiency.

3.2           Eco-Friendly polymers

Environmental degradation of polymers, Biodegradable, Photo-biodegradable polymers, Hydrolysis & Hydro biodegradable, Biopolymers & Bioplastics: polylactic acid, polyhydroxybutyrate, polycaprolactone, Concept of bioremediation.

Environmental degradation of polymers

Polymer degradation is a change in the properties—tensile strength, colour, shape, etc.of a polymer or polymer-based product under the influence of one or more environmental factors such as heat, light or chemicals such as acids, alkalis and some salts. These changes are usually undesirable, such as cracking and chemical disintegration of products or, more rarely, desirable, as in biodegradation, or deliberately lowering the molecular weight of a polymer for recycling. The changes in properties are often termed "aging".

In a finished product such a change is to be prevented or delayed. Degradation can be useful for recycling/reusing the polymer waste to prevent or reduce environmental pollution Degradation can also be induced deliberately to assist structure determination.

Polymeric molecules are very large (on the molecular scale), and their unique and useful properties are mainly a result of their size. Any loss in chain length lowers tensile strength and is a primary cause of premature cracking.

Biodegradable

Biodegradable is a term referred to all those things that can be decomposed by natural agents. Natural agents contain water, oxygen, acid rains, ultraviolet rays of the sun, microorganisms, etc.

Hydrolysis & Hydro biodegradable

This process occurs in polymers that are water sensitive active groups, especially those that take a lot of moisture.

Polymers that have ability for hydrolytic destruction usually have hetero atoms in the main or side chain hydrolysis: the scission of chemical functional groups by reaction with water. Some polymers are very stable to hydrolysis

Biopolymers & Bioplastics

Plastics derived from crude oil (such as petroleum) rely more on scarce fossil fuels. When plastics made from petroleum are burned, they release the carbon dioxide contained in the petroleum into the atmosphere, leading to global warming. Due to lack of proper disposal of these plastics, these affect wild life and aquatic life.

Concept of bioremediation

Bioremediation is a branch of biotechnology that employs the use of living organisms, like microbes and bacteria, in the removal of contaminants, pollutants, and toxins from soil, water, and other environments. Bioremediation may be used to clean up contaminated groundwater or environmental problems, such as oil spills.

3.3 Environmental pollution

Environmental Pollution can be defined as any undesirable change in physical, chemical, or biological characteristics of any component of the environment i.e. air, water, soil which can cause harmful effects on various forms of life or property. The term pollution can be defined as influence of any substance causing nuisance, harmful effects, and uneasiness to the organisms. Any substance causing Nuisance or harmful effects or uneasiness to the organisms, then that particular substance may be called as the pollutant.

a)  Air pollution

Air pollution refers to any physical, chemical or biological change in the air. It is the contamination of air by harmful gases, dust and smoke which affects the plants, animals, and humans drastically.

There is a certain percentage of gases present in the atmosphere. An increase or decrease in the composition of these gases is harmful to survival. This imbalance in the gaseous composition has resulted in an increase in earth’s temperature, which is known as global warming.

Types of Air Pollution

1. Primary Pollutants

The pollutants that directly cause air pollution are known as primary pollutants. Sulphur-dioxide emitted from factories is a primary pollutant.

2.     Secondary Pollutants

The pollutants formed by the intermingling and reaction of primary pollutants are known as secondary pollutants. Smog, formed by the intermingling of smoke and fog, is a secondary pollutant.

Causes of Air Pollution

Following are the important causes of air pollution:

The combustion of fossil fuels emits a large amount of sulphur dioxide. Carbon monoxide released by incomplete combustion of fossil fuels also results in air pollution.

The gases emitted from vehicles such as jeeps, trucks, cars, buses, etc. pollute the environment. These are the major sources of greenhouse gases and also result in diseases among individuals.

Ammonia is one of the most hazardous gases emitted during agricultural activities. The insecticides, pesticides and fertilizers emit harmful chemicals in the atmosphere and contaminate it.

Factories and industries are the main source of carbon monoxide, organic compounds, hydrocarbons, and chemicals. These are released into the air, degrading its quality.

In the mining process, the minerals below the earth are extracted using large pieces of equipment. The dust and chemicals released during the process not only pollute the air, but also deteriorate the health of the workers and people living in the nearby areas.

The household cleaning products and paints contain toxic chemicals that are released in the air. The smell from the newly painted walls is the smell of the chemicals present in the paints. It not only pollutes the air but also affects breathing.

Effects of Air Pollution

The hazardous effects of air pollution on the environment include:

Air pollution has resulted in several respiratory disorders and heart diseases among humans. The cases of lung cancer have increased in the last few decades. Children living near polluted areas are more prone to pneumonia and asthma. Many people die every year due to the direct or indirect effects of air pollution.

Due to the emission of greenhouse gases, there is an imbalance in the gaseous composition of the air. This has led to an increase in the temperature of the earth. This increase in earth’s temperature is known as global warming. This has resulted in the melting of glaciers and an increase in sea levels. Many areas are submerged underwater.

The burning of fossil fuels releases harmful gases such as nitrogen oxides and sulphur oxides in the air. The water droplets combine with these pollutants, become acidic, and fall as acid rain which damages human, animal and plant life.

The release of chlorofluorocarbons, halons, and hydro chlorofluorocarbons in the atmosphere is the major cause of depletion of the ozone layer. The depleting ozone layer does not prevent the harmful ultraviolet rays coming from the sun and causes skin diseases and eye problems among individuals.

The air pollutants suspend on the water bodies and affect the aquatic life. Pollution also compels the animals to leave their habitat and shift to a new place. This renders them stray and has also led to the extinction of a large number of animal species.

Control Measures

Following are the measures one should adopt, to control air pollution:

People should avoid using vehicles for shorter distances. Rather, they should prefer public modes of transport to travel from one place to another. This not only prevents pollution, but also conserves energy.

A large number of fossil fuels are burnt to generate electricity. Therefore, do not forget to switch off the electrical appliances when not in use. Thus, you can save the environment at the individual level. Use of energy-efficient devices such CFLs also controls pollution to a greater level.

a)     Water  Pollution

Water pollution can be defined as the contamination of water bodies. Water pollution is caused when water bodies such as rivers, lakes, oceans, groundwater, and aquifers get contaminated with industrial and agricultural effluents.

When water gets polluted, it adversely affects all lifeforms that directly or indirectly depend on this source. The effects of water contamination can be felt for years to come.

Types of Water  Pollution

1. Chemical pollution: The most common type of water pollution, chemicals can infiltrate both underground water sources and those sitting on the Earth's surface.
2. Groundwater pollution : agriculture is a key source of water pollution, especially for groundwater. Fertilisers and pesticides applied to crops can seep into the ground and contaminate underwater rivers and waterbeds, thus compromising the quality of wells, boreholes and other places from which groundwater is extracted for human use.
3. Microbiological pollution : Unlike most others on this list, microbiological pollution is a naturally occurring form of water contamination. Microorganisms such as bacteria, protozoa and viruses can infiltrate water supplies, causing diseases such as bilharzia and cholera. Humans are most susceptible to this kind of pollution in places where adequate water treatment systems are not yet in place.
4. Nutrient pollution : While they’re vital for underwater flora and fauna to flourish, an excess of nutrients can upset the delicate imbalance of water-based ecosystems. Fertilisers contain a high concentration of nutrients which, if they contaminate rivers, lakes and coastal areas, can cause algal blooming that can block out sunlight and inhibit the growth of other organisms.
5. Oxygen-depletion pollution : Another consequence of algal blooms is their consumption of oxygen supplies. This means that those species which depend upon oxygen to survive are killed off, while anaerobic ones thrive. Some anaerobic microorganisms are capable of producing ammonia, sulphides and other harmful toxins, which can make the water even more dangerous to animals (and humans, too).
6. Surface water pollution : which can lead to poor water quality, while accidental oil spills and negligent industries emptying waste into water bodies are also key contributors. Suspended matter, improperly discarded waste, such as fragments of plastic, rubber or other manmade materials, can find themselves into water sources and persist for a long time. Because they are too robust to dissolve in the water and too big to mix effectively with the molecules, they simply float on its surface and prevent oxygen and sunlight from penetrating below.

Causes of Water Pollution

The main causes of water pollution are attributed to

• Industrial activities
• Urbanization
• Religious and social practices
• Agricultural runoff
• Accidents (such as oil spills, nuclear fallouts etc)

Effects of Water Pollution

The effect of water pollution depends upon the type of pollutants and its concentration. Also, the location of water bodies is an important factor to determine the levels of pollution.

• Water bodies in the vicinity of urban areas are extremely polluted. This is the result of dumping garbage and toxic chemicals by industrial and commercial establishments.
• Water pollution drastically affects aquatic life. It affects their metabolism, behaviour, causes illness and eventual death. Dioxin is a chemical that causes a lot of problems from reproduction to uncontrolled cell growth or cancer. This chemical is bioaccumulated in fish, chicken and meat. Chemicals such as this travel up the food chain before entering the human body.
• The effect of water pollution can have a huge impact on the food chain. It disrupts the food-chain. Cadmium and lead are some toxic substances, these pollutants upon entering the food chain through animals (fish when consumed by animals, humans) can continue to disrupt at higher levels.
• Humans are affected by pollution and can contract diseases such as hepatitis through faecal matter in water sources. Poor drinking water treatment and unfit water can always cause an outbreak of infectious diseases such as cholera etc.
• The ecosystem can be critically affected, modified and de-structured because of water pollution

Control Measures

Water pollution, to a larger extent, can be controlled by a variety of methods. Rather than releasing sewage waste into water bodies, it is better to treat them before discharge. Practising this can reduce the initial toxicity and the remaining substances can be degraded and rendered harmless by the water body itself. If the secondary treatment of water has been carried out, then this can be reused in sanitary systems and agricultural fields.

A very special plant, the Water Hyacinth can absorb dissolved toxic chemicals such as cadmium and other such elements. Establishing these in regions prone to such kinds of pollutants will reduce the adverse effects to a large extent.

Some chemical methods that help in the control of water pollution are precipitation, the ion exchange process, reverse osmosis, and coagulation. As an individual, reusing, reducing, and recycling wherever possible will advance a long way in overcoming the effects of water pollution.

b)   Soil Pollution

Soil pollution refers to the contamination of soil with anomalous concentrations of toxic substances. It is a serious environmental concern since it harbours many health hazards. For example, exposure to soil containing high concentrations of benzene increases the risk of contracting leukaemia. An image detailing the discolouration of soil due to soil pollution is provided below.

Types of Soil Pollution

Soil pollution mainly occurs due to the following:

1. Industrial wastes

2. Urban wastes

3. Agricultural practices

4. Radioactive pollutants

5. Biological agents

Causes of Soil Pollution

Some common causes of soil pollution are listed below,

• Improper disposal of industrial waste: industries are believed to be one of the leading causes of soil pollution due to improper management and disposal of the toxic wastes generated during industrial activities.
• Excessive and inefficient usage of pesticides and fertilizers: the agriculture industry makes extensive use of chemical fertilizers and pesticides for the growth and maintenance of crops. However, excessive and inefficient use of these toxic chemicals can seriously contaminate the soil.
• Petroleum or diesel spills: leaks in fuel transportation pipes can cause fuel spills. These fuels are known to contain toxic hydrocarbons which can cause soil contamination.

Effects of Soil Pollution

Soil contaminants can exist in all three phases (solid, liquid, and gaseous). Therefore, these contaminants can find their way into the human body via several channels such as direct contact with the skin or through the inhalation of contaminated soil dust.

The short term effects of human exposure to polluted soil include:

• Headaches, nausea, and vomiting.
• Coughing, pain in the chest, and wheezing.
• Irritation of the skin and the eyes.
• Fatigue and weakness.

A variety of long-term ailments have been linked to soil pollution. Some such diseases are listed below.

• Exposure to high levels of lead can result in permanent damage to the nervous system. Children are particularly vulnerable to lead.
• Depression of the CNS (Central Nervous System).
• Damage to vital organs such as the kidney and the liver.
• Higher risk of developing cancer.

It can be noted that many soil pollutants such as petroleum hydrocarbons and industrial solvents have been linked to congenital disorders in humans. Thus, soil pollution can have several negative effects on human health.

Since soil pollution is often accompanied by a decrease in the availability of nutrients, plant life ceases to thrive in such soils. Soils contaminated with inorganic aluminium can prove toxic to plants. Also, this type of pollution often increases the salinity of the soil, making it inhospitable for the growth of plant life.

Plants that are grown in polluted soil may accumulate high concentrations of soil pollutants through a process known as bioaccumulation. When these plants are consumed by herbivores, all the accumulated pollutants are passed up the food chain. This can result in the loss/extinction of many desirable animal species. Also, these pollutants can eventually make their way to the top of the food chain and manifest as diseases in human beings.

• Since the volatile contaminants in the soil can be carried away into the atmosphere by winds or can seep into underground water reserves, soil pollution can be a direct contributor to air and water pollution.
• It can also contribute towards acid rain (by releasing huge quantities of ammonia into the atmosphere).
• Acidic soils are inhospitable to several microorganisms that improve soil texture and help in the decomposition of organic matter. Thus, the negative effects of soil pollution also impact soil quality and texture.

Control Measures

Several technologies have been developed to tackle soil remediation. Some important strategies followed for the decontamination of polluted soil are listed below.

• Excavation and subsequent transportation of polluted soils to remote, uninhabited locations.
• Extraction of pollutants via thermal remediation – the temperature is raised in order to force the contaminants into the vapour phase, after which they can be collected through vapour extraction.
• Mycoremediation involves the use of fungi for the accumulation of heavy metal contaminants.

c)    Marine pollution

Types

1. Garbage

Garbage and plastic debris (bags, straws, cutlery, six-pack rings, water bottles, etc.) is a huge threat to the survival of marine fauna. Trash is ingested, causes entanglement, and suffocates our ocean friends.

2. Sunscreen and Other Topicals

Sunscreen, body lotion, insect repellents, essential oils, hair products, and makeup can all make their way into the water via the bodies of swimmers. These substances negatively affect algae, sea urchins, fish, and mammals in the ocean as well as coral reefs.

3. Oil Seepage

While oil seepage from highly pressurized seafloor rock does occur naturally in some areas around the world, there are plenty of other ways humans are adding to the problem. Oil from vehicles on the road wash off and trickle into the ocean. Boats sometimes spill oil directly into the water. Of course, there are also occasional catastrophic oil spills. No matter how the oil seeps, it’s harmful to marine life.

4. Sewage

Sometimes our sewer and septic systems don’t operate properly or do not remove enough nitrogen and phosphorus before discharging our gray water into the waterways. The EPA estimates that 10-20% of septic systems fail at some point in their operational lifetimes. This can happen due to aging infrastructure, inappropriate design, overloaded systems, and poor maintenance. The resulting pollution comes from soaps and detergents, human wastewater, and solid sludge.

5. Agricultural and Aquaculture Runoff

Nitrogen-rich fertilizers and pesticides applied by inland farmers run off into the ocean through rivers after a rainstorm. Also, the aquaculture industry has been known to release uneaten food, antibiotics, and parasites from fish farms into nearby waters.

6. Industrial Waste

Industrial waste is a huge issue when it comes to ocean dumping. Dangerous toxins that accumulate include radioactive waste, arsenic, lead, fluoride, cyanide, and many other high contaminants. This waste infects the water and sea life…including the ones that we humans eat!

7. Eutrophication

Eutrophication creates areas that can’t support ocean life. Eutrophication frequently occurs in coastal waters due to a lack of oxygen dissolved in the water and an excess of nutrients, mainly nitrogen and phosphorus. There are currently over 400 dead zones all over the world’s coastlines. The biggest concern is nutrient pollution that comes out with fresh water and into the ocean. This pollution comes from run-off from municipal and industrial wastewater treatment plants and industrial-scale agricultural farms.

8. Carbon Dioxide

Carbon dioxide is produced by burning fossil fuels, and as the atmospheric concentration of CO2 gas increases (faster than they have in the last 300 million years), our oceans are becoming more acidic, since carbon dioxide dissolves into the water. This change in the pH of ocean water has disastrous effects on corals and shellfish.

9. Noise

You may have not considered sound to be a pollutant, but take a moment to think about it. Many ocean species rely heavily on their sense of hearing. Noise that is generated by passing cargo ships, sonar, oil exploration and drilling, commercial fishing, recreational jet skis, etc. causes confusion and interferes with the acoustic information that is relied upon for survival of the fittest in the water below.

In essence, pollution of the water is not any different than pollution on land or in the air. There are terrible ramifications. Thinking “out of sight, out of mind” doesn’t solve any problems and will only make things worse in the end.

Causes

1. Sewage

Pollution can enter the ocean directly. Sewage or polluting substances flow through sewage, rivers, or drainages directly into the ocean. This is often how minerals and substances from mining camps find their way into the ocean.

The release of other chemical nutrients into the ocean’s ecosystem leads to reductions in oxygen levels, the decay of plant life, and a severe decline in the quality of the seawater itself. As a result, all levels of oceanic life, plants and animals, are highly affected.

2. Toxic Chemicals From Industries

Industrial and agricultural waste is another most common form of wastes that is directly discharged into the oceans, resulting in ocean pollution.

The dumping of toxic liquids in the ocean directly affects marine life as they are considered hazardous, and secondly, they raise the temperature of the ocean, a phenomenon known as thermal pollution, as the temperature of these liquids is quite high. Animals and plants that cannot survive at higher temperatures eventually perish.

3. Land Runoff

Land runoff is another source of pollution in the ocean. This occurs when water infiltrates the soil to its maximum extent, and the excess water from rain, flooding or melting flows over the land and into the ocean.

Often, this water picks up man-made, harmful contaminants that pollute the ocean, including fertilizers, petroleum, pesticides and other forms of soil contaminants. Fertilizers and waste from land animals and humans can be hugely detrimental to the ocean by creating dead zones.

4. Large Scale Oil Spills

Ship pollution is a huge source of ocean pollution, the most devastating effect of which is oil spills. Crude oil lasts for years in the sea and is extremely toxic to marine life, often suffocating marine animals to death once it entraps them. Crude oil is also extremely difficult to clean up, unfortunately, meaning that when it is split, it is usually there to stay.

5. Ocean Mining

Ocean mining in the deep sea is yet another source of ocean pollution. Ocean mining sites drilling for silver, gold, copper, cobalt, and zinc create sulfide deposits up to three and a half thousand meters down into the ocean.

While we yet to have the gathering of scientific evidence to fully explain the harsh environmental impacts of deep-sea mining, we do have a general idea that deep-sea mining causes damage to the lowest levels of the ocean and increases the toxicity of the region. This permanent damage dealt also causes leaking, corrosion and oil spills that only drastically further hinder the ecosystem of the region.

6. Littering

Pollution from the atmosphere is, believe it or not, a huge source of ocean pollution. This occurs when far inland objects are blown by the wind over long distances and end up in the ocean.

These objects can be anything from natural things like dust and sand to man-made objects such as debris and trash. Most debris, especially plastic debris, cannot decompose and remains suspended in the ocean’s current for years.

Animals can become snagged on the plastic or mistake it for food, slowly killing them over a long period of time. Animals who are most often the victims of plastic debris include turtles, dolphins, fish, sharks, crabs, sea birds, and crocodiles.

Effects

1. Effect of Toxic Wastes on Marine Animals

The oil spill is dangerous to marine life in several ways. The oil spilled in the ocean could get on to the gills and feathers of marine animals, which makes it difficult for them to move or fly properly or feed their children. The long term effect on marine life can include cancer, failure in the reproductive system, behavioural changes, and even death.

2. Disruption to the Cycle of Coral Reefs

Oil spill floats on the surface of the water and prevents sunlight from reaching to marine plants and affects the process of photosynthesis. Skin irritation, eye irritation, lung and liver problems can impact marine life over a long period of time.

3. Depletes Oxygen Content in Water

Most of the debris in the ocean does not decompose and remain in the ocean for years. It uses oxygen as it degrades. As a result of this, oxygen levels go down. When oxygen levels go down, the chances of survival of marine animals like whales, turtles, sharks, dolphins, penguins for a long time also goes down.

4. Failure in the Reproductive System of Sea Animals

Industrial and agricultural wastes include various poisonous chemicals that are considered hazardous for marine life. Chemicals from pesticides can accumulate in the fatty tissue of animals, leading to failure in their reproductive system.

5. Effect on Food Chain

Chemicals used in industries and agriculture get washed into the rivers and from there are carried into the oceans. These chemicals do not get dissolved and sink at the bottom of the ocean. Small animals ingest these chemicals and are later eaten by large animals, which then affects the whole food chain.

6. Affects Human Health

Animals from impacted food chain are then eaten by humans, which affects their health as toxins from these contaminated animals get deposited in the tissues of people and can lead to cancer, birth defects or long term health problems.

Control measures

1. Reducing the Use of Plastic Products

These plastics then take thousands of years to decompose, during which time it poses a terrible threat to life in the oceans. Thus, reduction in the use of plastic products could help in significantly reducing the rates of ocean pollution.

2. Use Reusable Bottles and Cutlery

Use and throw bottles and cutlery, too, are an immense contributor to ocean pollution. We must not forget that most of the non-reusable bottles and cutlery are made out of either plastic or Styrofoam. Both these materials require a few hundred or thousand years to decompose.

3. Recycle Whatever You Can

With the increase in population, it is true that the waste produced would also increase significantly. As finding dumping grounds become more and more difficult, a lot of the wastes find their way to the ocean beds. These wastes that are dumped in the ocean remain there for a long time, affecting marine life.

One of the useful ways to reduce waste production is recycling. Before throwing things away, we could check if something is recyclable. Then the products that can be recycled can be taken to the recycling center nearby.

4. Stop Littering the Beach, and Start Cleaning It

The beach is undoubtedly one of the loveliest places to visit and hang out in. As a result of this, there is a lot of littering around as well. The first and foremost thing that really needs to stop is this. Abundant dustbins should be placed on the beaches.

If someone is seen littering, they must be stopped immediately, and certain strict rules and regulations must be followed at all times. Also, if the beach seems untidy, we could pick up the wastes and throw it in the dustbin.

5. Reducing the Use of Chemical Fertilizers

Runoffs, too, pollute the oceans immensely. To prevent this, the use of chemical fertilizers must also be controlled and regulated. It must be remembered that excess use of chemical fertilizers harms not only the soil but also the water bodies nearby and, ultimately, the ocean. These runoffs are so toxic that they can very easily kill marine life.

6. Reducing the Energy Use

As the population increases, our demand for energy increases too. A major chunk of this energy is produced from petroleum. This petroleum is obtained by the drilling of the ocean beds. Any spillage during the procedure could harm marine life. Not only that, but the procedure itself also violates the marine ecological balance. So by controlling our energy use, we could also solve the problem of ocean pollution.

d)   Noise Pollution

Noise is the unpleasant and undesirable sound which leads to discomfort to human beings. The intensity of sound is measured in decibels (dB). The faintest sound which can be heard by the Human ear is 1 Db. Due to increasing noise around the civilizations; noise pollution has become a matter of concern. Some of its major causes are vehicles, aircraft, industrial machines, loudspeakers, crackers, etc. Some other appliances also contribute to noise pollution like television, transistor, radio, etc. when used at high volume.

Types of Noise Pollution

Following are the three types of pollution:

It mainly consists of traffic noise which has increased in recent years with the increase in the number of vehicles. The increase in noise pollution leads to deafening of older people, headache, hypertension, etc.

The noise from gadgets, household utensils etc. Some of the main sources are musical instruments, transistors, loudspeakers etc.

It is the high-intensity sound which is caused by heavy industrial machines. According to many researches industrial noise pollution damages the hearing ability to around 20%.

Causes of Noise Pollution

Following are the causes and sources of noise pollution:

• Industrialization: Industrialization has led to an increase in noise pollution as the use of heavy machinery such as generators, mills, huge exhaust fans, etc are used resulting in the production of unwanted noise.
• Vehicles: Increased number of vehicles on the roads are the second reason for noise pollution.
• Events: Weddings, public gatherings involve loudspeakers to play music resulting in the production of unwanted noise in the neighbourhood.
• Construction sites: Mining, construction of buildings, etc add to the noise pollution.

Effects of Noise Pollution

Noise pollution can be hazardous to human health in the following ways:

• Hypertension: It is a direct result of noise pollution which is caused due to elevated blood levels for a longer duration.
• Hearing loss: Constant exposure of human ears to loud noise that are beyond the range of sound that human ears can withstand damages the eardrums resulting in loss of hearing.
• Sleeping disorders: Lack of sleep might result in fatigue and low energy level throughout day affecting everyday activities. Noise pollution hampers the sleep cycles leading to irritation and uncomfortable state of mind.
• Cardiovascular issues: Heart related problems such as blood pressure level, stress, and cardiovascular diseases might come up in a normal person and person suffering from any of these diseases might feel the sudden shoot up in the level.

Control Measures

Some noise pollution preventive measures are provided in the points below.

• Honking in public places like teaching institutes, hospital, etc. should be banned.
• In commercial, hospital, and industrial buildings adequate soundproof systems should be installed.
• Musical instruments sound should be controlled to desirable limits.
• Dense tree cover is useful in noise pollution prevention.
• Explosives should be not used in forest, mountainous, and mining areas.

e)    Thermal pollution

Thermal pollution is the degradation of water quality by any process that changes ambient water temperature. A common cause of thermal pollution is the use of water as a coolant by power plants and industrial manufacturers.

The term thermal pollution has been used to indicate the detrimental effects of heated effluent discharge by various power plants. It denotes the impairment of quality and deterioration of aquatic and terrestrial environment by various industrial plants like thermal, atomic, nuclear, coal-fired plants, oil field generators, factories, and mills.

Sources of Thermal Pollution

1.  Nuclear Power Plant

2. Coal-fired power Plant

3. Industrial Effluents

4. Domestic Sewage

5. Hydro-electric power

6. Thermal Power Plant

The discharged effluents of these sources have a higher temperature than the intake water that reduces the concentration of oxygen from the water which causes the deleterious effects on the marine ecosystem.

Harmful effects of the thermal pollution

1. Reduction in dissolved Oxygen

The pollutant from various industrial plants are heated decreases the concentration of oxygen with an increase in the temperature of water.

2. Change in water properties

The decrease in density, viscosity and solubility of gases in water increases the setting speed of suspended particles which seriously affect the food supplies of aquatic organism.

3. Increase in toxicity

The concentrated pollutant causes the rise in the temperature of water which increases the toxicity of the poison present in water. The toxicity in water will increase the death rate in marine life.

4. Disruption of Biological activities

Temperature changes disrupt the entire marine ecosystem because changes in temperature causes change in physiology, metabolism and biological process like respiration rate, digestion, excretion and development of an aquatic organism.

How biochemical cycles stabilizes the biosphere?

5. Damage of biotic organism

Aquatic organisms like juvenile fish, plankton, fish, eggs, larva, algae and protozoa which pass through screens and condenser cooling system are extremely sensitive to abrupt temperature changes. They are habitual of warmer water may suddenly face increase or decrease in temperature of water bodies and thus die because of sudden changes in the temperature of water.

Prevention for Thermal Pollution

The following measures can be taken to prevent or control high temperature caused by thermal pollution:

1. Heated water from the industries can treated before discharging directly to the water bodies.

2. Heated water from the industries can be treated by the installation of cooling ponds and cooling towers.

3. Industrial treated water can be recycled for domestic use or industrial heating.

4. Through artificial lakes: In this lake Industries can discharge their used or heated water at one end and water for cooling purposes may be withdrawn from the other end. The heat is eventually dissipated through evaporation.

f)      Nuclear Hazards

According to International Atomic Energy Agency (IAEA), a nuclear and radiation accidents/ hazards is an event that has led to significant consequences to people, the environment or the facility.  Nuclear hazards. Risk or danger to human health or the environment exposed by the radiation emanating from the atomic nuclei is called as nuclear hazard. Nuclear hazard is an actual or potential release of radioactive material at a commercial nuclear power plant or a transportation accident.

Nuclear power plant accidents:

• The SL-1 accident(1961)
• The Three Mile Island Accident(1979)
• Chernobyl Disaster (1986)
• Fukushima Daiichi nuclear disaster(2011)

Human Health Risks

• Studies shown that the health effects due to radiation are dependent on the level of dose, kind of radiation, duration of exposure and types of cells irradiated. Radiation effects can be somatic or genetic.
• Radioactive iodine and caesium are being released into the environment from the malfunctioning nuclear reactors in Japan.
• As radioactive material decays, or breaks down, the energy released into the environment has two ways of harming a body that is exposed to it.
• It can directly kill cells, or it can cause mutations to DNA. If those mutations are not repaired, the cell may turn cancerous.
• Children are most at risk for thyroid cancer, since their thyroid glands are 10 times smaller than those of adults as the radioactive iodine would be more concentrated in them. The Chernobyl accident released a plume of radioactive materials into the atmosphere in a fraction of a second. In the following years, the incidence of thyroid cancer among those exposed as children increased in Ukraine and nearby countries.

Control measures

• Laboratory generated nuclear wastes should be disposed off safely and scientifically.
• Nuclear power plants should be located in areas after careful study of the geology of the area, tectonic activity and meeting other established conditions.
• Appropriate protection against occupational exposure
• Leakage of radioactive elements from nuclear reactors, careless use of radioactive elements as fuel and careless handling of radioactive isotopes must be prevented.
• Safety measure against accidental release of radioactive elements must be ensured in nuclear plants.
• Unless absolutely necessary, one should not frequently go for diagnosis by x-rays.
• Regular monitoring of the presence of radioactive substance in high risk area should be ensured.

3.4           Solid waste management- Causes, effects and control measures of urban and industrial wastes

Causes

1. Lack of Policies to Control Pollution

Lack of effective policies and poor enforcement drive allowed many industries to bypass laws made by the pollution control board, which resulted in mass-scale pollution that affected the lives of many people.

2. Unplanned Industrial Growth

In most industrial townships, unplanned growth took place wherein those companies flouted rules and norms and polluted the environment with both air and water pollution.

3. Use of Outdated Technologies

Most industries still rely on old technologies to produce products that generate a large amount of waste. To avoid high cost and expenditure, many companies still make use of traditional technologies to produce high-end products.

4. Presence of a Large Number of Small Scale Industries

Many small scale industries and factories that don’t have enough capital and rely on government grants to run their day-to-day businesses often escape environment regulations and release a large number of toxic gases in the atmosphere.

5. Inefficient Waste Disposal

Water pollution and soil pollution are often caused directly due to inefficiency in the disposal of waste. Long term exposure to polluted air and water causes chronic health problems, making the issue of industrial pollution into a severe one. It also lowers the air quality in surrounding areas, which causes many respiratory disorders.

6. Leaching of Resources From Our Natural World

Industries do require a large amount of raw material to make them into finished products. This requires the extraction of minerals from beneath the earth. The extracted minerals can cause soil pollution when spilled on the earth. Leaks from vessels can cause oil spills that may prove harmful to marine life.

7. Natural Resource Use

Raw material is a must for industries, which often requires them even pulling out underground elements. One of the most common forms of leaching from natural resources is fracking for oil.

When industries extract minerals, the process causes soil pollution and also causes oil leaks and spills that are harmful and even deadly to people and animals.

Effects

1. Water Pollution

The effects of industrial pollution are far-reaching and liable to affect the ecosystem for many years to come. Most industries require large amounts of water for their work. When involved in a series of processes, the water comes into contact with heavy metals, harmful chemicals, radioactive waste, and even organic sludge.

These are either dumped into open oceans or rivers. As a result, many of our water sources have a high amount of industrial waste in them, which seriously impacts the health of our ecosystem. The same water is then used by farmers for irrigation purposes, which affects the quality of food that is produced.

2. Soil Pollution

Soil pollution is creating problems in agriculture and destroying local vegetation. It also causes chronic health issues to the people that come in contact with such soil on a daily basis.

3. Air Pollution

Air pollution has led to a steep increase in various illnesses, and it continues to affect us on a daily basis. With so many small, mid and large scale industries coming up, air pollution has taken a toll on the health of the people and the environment.

4. Wildlife Extinction

By and large, the issue of industrial pollution shows us that it causes natural rhythms and patterns to fail, meaning that the wildlife is getting affected in a severe manner. Habitats are being lost, species are becoming extinct, and it is harder for the environment to recover from each natural disaster.

Major industrial accidents like oil spills, fires, the leakage of radioactive materials and damage to property are harder to clean-up as they have a higher impact in a shorter timeframe.

5. Global Warming

With the rise in industrial pollution, global warming has been increasing at a steady pace. Smoke and greenhouse gases are being released by industries into the air, which causes an increase in global warming.

Melting of glaciers, extinction of polar bears, floods, tsunamis, hurricanes are few of the effects of global warming.

6. Biodiversity Loss

Industrial pollution continues to cause significant damage to the earth and all of its inhabitants due to chemical wastes, pesticides, radioactive materials etc. It affects wildlife and ecosystems and disrupts natural habitats. Animals are becoming extinct, and habitats are being destroyed.

The increasing liquid, solid and hazardous wastes undermine ecosystem health and impact on food, water and health security. Industrial pollution disasters, including oil spills and radioactive leakage, take years to decades to clean up.

7. Atmospheric Deposition

Cadmium enrichment of soil can also be associated with industrial pollution. Topsoils contaminated by mine spoil showed a wide range of Cd concentrations.

Industrial effluents are commonly discharged to surface water drainage systems after clarification in tailing ponds. Recent investigations have disclosed very high concentrations of Cd in the overbank and bottom sediments of the rivers.

Control Measures of Urban And Industrial Wastes

An integrated waste management strategy includes three main components

1. Source reduction

2. Recycling

3. Disposal

Source reduction is one of the fundamental ways to reduce waste. This can be done by using less material when making a product, reuse of products on site, designing products or packaging to reduce their quantity. On an individual level we can reduce the use of unnecessary items while shopping, buy items with minimal packaging, avoid buying disposable items and also avoid asking for plastic carry bags.

Recycling is reusing some components of the waste that may have some economic value. Recycling has readily visible benefits such as conservation of resources reduction in energy used during manufacture and reducing pollution levels. Some materials such as aluminium and steel can be recycled many times. Metal, paper, glass and plastics are recyclable. Mining of new aluminium is expensive and hence recycled aluminium has a strong market and plays a significant role in the aluminium industry. Paper recycling can also help preserve forests as it takes about 17 trees to make one ton of paper. Crushed glass (cullet) reduces the energy required to manufacture new glass by 50 percent. Cullet lowers the temperature requirement of the glassmaking process thus conserving energy and reducing air pollution.

3.5 Role of an individual in prevention of pollution

• Individuals should minimize wastage of resources such as electricity. Every unit of electricity saved is equivalent unit of electricity produced as it not only saves the fuel that would be used to produce that electricity, but also help to prevent pollution that is accompanied by burning of that fuel. Therefore, person should always switch off appliances when not in use.
• Individuals should prefer walking or use cycles instead of using motor vehicles, especially when distances to be travelled are small.
• Individuals can make considerable contribution by using mass transport (buses, trains, etc) instead of using personal vehicles.
• When going to workplace, colleagues from nearby localities should pool vehicles instead of going in individual personal vehicles.
• Taking personal vehicles for periodic pollution checks at centres approved by authorities.
• Individuals should reuse items whenever possible.
• Products that are made of recycled material should be given preference.
• Use gunny bags made of jute instead of plastic bags.
• Take part in environment conservation drives such as tree planting drives.
• Use water resources efficiently.
• Use renewable resources by installing equipment such as solar heaters and using solar cookers.
• Dispose potentially harmful products such as cells, batteries, pesticide containers, etc properly.
• Use of refrigerators should be minimised wherever possible as they are main source of CFC, which is responsible for Ozone layer depletion.
• Follow and promote family planning, as more population means more resources utilized and more resources utilized imply more pollution.
• Avoid making noise producing activities such as listening to loud music.
• Use handkerchiefs instead of paper tissues.
• Organize drives to clean streets and clean drains with help of other people of locality.
• Spread awareness and inspire other people to prevent pollution. Individuals should be encouraged to acquire information and innovations from world over and implement them locally.

3.6   Pollution case studies

1. Taj Trapezium case

Taj Mahal The “Taj Mahal” is the “King of Emperor” amongst world wonder. It is one of the most priceless national monuments and also a glorious reputation to the men’s achievements in architecture. He chemical industries and refinery at Mathura are source of damage “Taj Mahal”. SO3 came from the industry react with moisture in atmosphere and form the “Acid Rain”. This will make corroding effect on clean white marble. The judgment vigorously applied the “precautionary principle” and in May 1999,the Central Government constituted the Taj Trapezium Pollution Authority.

The world’s worst industrial accident occurred in Bhopal city, M.P. On midnight of 3 Dec 1984. Who manufactures some carbonate pesticides, using Methyl isocyanate(MIC). The reactor exploded due to the failure of the cooling system .

Effects

• Lower amount of MIC it affects lungs, eyes and cause irritation on skin.
• Higher amount of MIC cause O2 remove from lungs and cause death .
• 5000 persons were killedMIC spread over 40 sq.km area  .
• 65000 people suffer from eye & reparatory disorder and 1000 person became blind .

3.7   Disaster management: floods, earthquake, cyclone and landslides

Disaster is a sudden calamity which brings misfortune and miseries to humanity.

Types:

1. Natural disaster

2. Man-made disaster

Natural disaster: Floods, Cyclones, earth quakes, landslides. Etc

Man-made disaster: Accidents, pollutions, fire accidents, bomb blasts.

FLOODS :

Defined as a situation when the river over flows is banks and the water spreads in the surrounding areas and submerging them. It usually occurs in rainy season.

Causes

• Heavy intense rain fall
• Melting of accumulated snow
• Melting of snow combine with rains
• Over saturated soil when the ground cannot hold any more water
• Urbanization

Control

1. Forecast, warning and advice should be provided through media to educate aware people about steps to be taken on the event of mishap.
2. Valuable house hold items, animals and materials like food, clothes, medicines etc. should be shifted to safe places.
3. Elderly people and children should be evacuated to safer place on emergency.
4. By the construction of protective works.

EARTHQUAKE :

Sudden vibration caused on the earth surface due to sudden release of tremendous amount of energy stored in the rocks under the earth crust is called earthquake.

A focus of an earthquake is the point of initial movement. Epicenter is the point on the surface directly above the focus.

Measure of Earth quake-Richter scale

Magnitude of earthquake is a measure of amount of energy released in the earthquake. Earthquake is recorded by seismograph.

• Less than 4-insignificant
• 4-4.9-minor
• 5-5.9-damaging
• 6-6.9-destructive,
• 7-7.9-major
• Above 8- great
• Primary effect of earth quake: Shaking

Sometimes a permanent vertical or horizontal displacement of the ground .This affects people bridges, dams, pipe lines.

Secondary effects

Rocks slides, flood caused by the subsidence of land, coastal areas are severely damaged .Earth quake generated water wave called Tsunami and also called tidal waves that travel as fast as 950km/hr.

Precautionary measures

• People should come out of their homes and stay in the open till the tremors subside.
• People already out of home should stay away from the building electric poles, trees and any tall objects that have chances of falling down.
• After the earth quake relief camp by the Government or other social groups should be conducted for the affected people.

CYCLONE :

An atmospheric closed circulation, rotating anti- clock wise in the northern hemi sphere and clock wise in southern hemisphere .

Cyclone is an area of low pressure in the centre and high pressure outside. Powerful swirling storm that measures from 300- 500 km in diameter. The wind in the centre of cyclone blows in the speed of 120km/hr.

In India cyclone originates from Bay of Bengal are more in number and intensity. Relatively less south-west Indian Ocean and Arabian Sea. In India cyclones occur during October-December or April-May.

EFFECTS

• Damage to human life, crops, roads, transport, and communication could be heavy.
• Cyclone slows down developmental activities of the area.

Management

• Meteorological Departments forecast by satellite images the weather conditions which reveal the strength and intensity of the storm.
• Radar systems is used to detect cyclone and cyclone warning.
• The effect of cyclone is minimized by planting more trees on the coastal belts, constructional dams, wind breaks etc.

LAND SLIDES :

A landslide is a sudden collapse of large mass of hill side.

Types

• Shallow disrupted land slide
• Decoherent landslide

Factors causing landslides

• Caused by rain forces increasing top material weight, lubricating the material layer or making slope top steep.
• Gravity-gravity works more effectively on steeper slopes
• Weather: Most slides occur during or after heavy rains

Effects

• Flow deposit blocks the road and diverts the passage

Prevention

• Revegetate the area to prevent the surface erosion .Inspect and repair all drainage system. Collect runoff from roofs and improved areas and convey water from the steep slopes in a well designed pipe system.

3.8           Chemical toxicology-Terms related to toxicity, impact of chemicals (Hg, As, Cd, Cr, Pb) on environment.

Metallic chemical element that has relatively high density and is toxic or poisonous at low concentrations’’ Atomic weight of Hg: 200.59, Pb: 207.2 Vs Si: 28.086. Most common heavy metal contaminants are Cd, Cr, Ar, Hg, Pb, and Zn. Importance; Can’t be subject to chemical degradation beyond its elemental state.

• Erosion of rocks
• Forest fires ,
• Volcanic activity.

ANTHROPOGENIC EMISSIONS

• Coal fired power stations, Contaminated waste dumping, Industrial discharges ,Sewage, car exhausts.
• Bind with sediments - deposited on the seabed enter the marine environment - Dredging ,Trawling & Severe weather.

REFERENCES :

1. Textbook of Environmental Science by Deeksha Dave and E.Sai Baba Reddy, Cengage

Publications.

2. Text book of Environmental Sciences and Technology by M.Anji Reddy, BS Publication.

3. Comprehensive Environmental studies by J.P.Sharma, Laxmi publications.

4. Environmental sciences and engineering – J. Glynn Henry and Gary W. Heinke – Prentice hall of

India Private limited.

5. A Text Book of Environmental Studies by G.R.Chatwal, Himalaya Publishing House

6. Introduction to Environmental engineering and science by Gilbert M. Masters and Wendell P. Ela -

Prentice hall of India Private limited.