Unit 1.docx

ENVIRONMENTAL TECHNOLOGY (Theory) Course code:16ET32/42

CIE Marks: 50

Hrs/Week: L:T:P:S :2:0:0:0

SEE Marks: 50

Credits: 02

SEE Duration (Theory): 90 min

Course learning objectives: The student will be able to 1. Understand the various components of environment and the significance of the sustainability of healthy environment. 2. Recognize the implications of different types of the wastes produced by natural and anthropogenic activity. 3. Learn the strategies to recover the energy from the waste. Design the models that help mitigate or prevent the negative impact of proposed activity on the environment UNIT-1 Introduction: Ecosystem – Types and structure of ecosystem. Components of environment,Environmental education, Environmental act & regulations. Global environmental issues, ISO 14000, Environmental Impact Assessment and Challenges.05 Introduction: (envirotech), green technology (greentech) or clean technology (cleantech) is the application of one or more of environmental science, green chemistry, environmental monitoring and electronic devices to monitor, model and conserve the natural environment and resources, and to curb the negative impacts of human involvement. The term is also used to describe sustainable energy generation technologies such as photovoltaic’s etc. Sustainable development is the core of environmental technologies. Ecosystems - Types and structure of ecosystem Ecosystems are functional units that result from the interactions of abiotic & biotic components at a particular area within the environment. Like all other systems they are a combination of interacting processes within biotic components & between biotic & abiotic components. Ecosystems may be microecosystem (as small as a drop of water) or macro-ecosystem (as large as ocean). It may be either temporary (ex: field of cultivated crops) or permanent (ex: a forest or ocean). The boundaries are not

fixed in any objective way, although sometimes they seem obvious, as with the shoreline of a small pond. Usually the boundaries of an ecosystem are chosen for practical reasons having to do with the goals of the particular study. An ecosystem’s character changes as community members and physical contexts change, sometimes crossing a threshold of tolerance within the system that results in its inability to return to its previous form. Components of an Ecosystem Abiotic Components: Structurally abiotic components include: ● Physical factors such as light, temperature, precipitation, humidity, wind, soil, etc ● Inorganic substances include minerals and gases. ● Organic substances such as carbohydrates, proteins , lipids and humans Biotic Components: They include the entire living organisms. They may be divided into two groups. ● Autotrophs or producers: They are self-nourishing green plants and certain photosynthetic or chemosynthetic bacteria which convert the light energy into chemical energy in the form of organic compounds needed by the plants for their growth and development. ● Heterotrophs or Consumers: Organisms which feed directly or indirectly on producers are called consumers. An organism that feed upon the producers is called primary consumer or herbivores and the organisms which feed on the primary consumer is called a secondary consumer or carnivore. Animals that feed both on plants and animals are known as omnivores. Structure of an Ecosystem: ● The particular pattern of interrelationship that exists between the components in an ecosystem is the structure of the ecosystem. ● The structure of the ecosystem may be determined by a single abiotic factor known as limiting factor. For most of the land areas, the amount of rainfall is the limiting factor which is responsible for the categorization of the ecosystem into forests, grasslands or deserts. Energy flow and nutrient cycling can only occur as long as certain structure is maintained. Processes of Ecosystems Ecosystems function through two important and interlinked processes & are energy flow & material cycling. Energy flow is the movement of energy, starting with the sun, and passing from one organism to another. Energy enters the biological system as light energy, or photons, is transformed into chemical energy in organic molecules by cellular processes including photosynthesis and respiration, and ultimately is converted to heat energy. This energy is dissipated, meaning it is lost to the system as heat; once it is lost it cannot be recycled. Without the continued input of solar energy, biological systems would quickly shut down. Thus the earth is an open system with respect to energy.

Ecosystem Structure: At a basic functional level, ecosystem generally contains primary producers (plants) capable of harvesting energy from the sun through the process called photosynthesis. This energy then flows through the food chain. Next come consumers. Consumers could be primary consumers (herbivores) or secondary consumers (carnivores). These consumers feed on the captured energy. Decomposers work at the bottom of the food chain. Dead tissues and waste products are produced at all levels. Scavengers, detritivores and decomposers not only feed on this energy but also break organic matter back into its organic constituents. It is the microbes that finish the job of decomposition and produce organic constituents that can again be used by producers. Energy that flows through the food chain i.e. from producers to consumers to decomposers is always inefficient. That means less energy is available at secondary consumers level than at primary producers level. It’s not surprising but amount of energy produced from place to place varies a lot due to amount of solar radiation and the availability of nutrients and water. Types of Ecosystem

There are very many types of ecosystems out there, but the three major classes of ecosystems, sometimes referred to as ‘biomes’, which are relatively contained, are the following: ●

Freshwater Ecosystems

●

Terrestrial Ecosystems

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Ocean Ecosystems

Freshwater Ecosystems These can then be broken up into smaller ecosystems. For instance, in the freshwater ecosystems we find: Pond Ecosystems – These are usually relatively small and contained. Most of the time they include various types of plants, amphibians and insects. Sometimes they include fish, but as these cannot move around as easily as amphibians and insects, it is less likely, and most of the time fish are artificially introduced to these environments by humans. River Ecosystems – Because rivers always link to the sea, they are more likely to contain fish alongside the usual plants, amphibians and insects.

These sorts of ecosystems can also include birds because birds often hunt in and around water for small fish or insects.

As is clear from the title, freshwater ecosystems are those that are contained to freshwater environments. This includes, but is not limited to, ponds, rivers and other waterways that are not the sea (which is, of course, saltwater and cannot support freshwater creatures for very long). Freshwater ecosystems are actually the smallest of the three major classes of ecosystems, accounting for just 1.8% of the total of the Earth’s surface. The ecosystems of freshwater systems include relatively small fish (bigger fish are usually found in the sea), amphibians (such as frogs, toads and newts), insects of various sorts and, of course, plants. The absolutely smallest living part of the food web of these sorts of ecosystems is plankton, a small organism that is often eaten by fish and other small creatures.

Terrestrial Ecosystems

Terrestrial ecosystems are many because there are so many different sorts of places on Earth. Some of the most common terrestrial ecosystems that are found are the following: ●

Rainforests – Rainforests usually have extremely dense ecosystems because there are so many different types of animals all living in a very small area.

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Tundra – As mentioned above, tundra usually have relatively simple ecosystems because of the limited amount of life that can be supported in these harsh conditions.

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Deserts – Quite the opposite of tundra in many ways, but still harsh, more animals live in the extreme heat than live in the extreme cold of Antarctica, for instance.

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Savannas – These differ from deserts because of the amount of rain that they get each year. Whereas deserts get only a tiny amount of precipitation every tea, savannas tend to be a bit wetter which is better for supporting more life.

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Forests – There are many different types of forests all over the world including deciduous forests and coniferous forests. These can support a lot of life and can have very complex ecosystems.

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Grasslands – Grasslands support a wide variety of life and can have very complex and involved ecosystems.

Since there are so many different types of terrestrial ecosystems, it can be difficult to make generalizations that cover them all.

Because terrestrial ecosystems are so diverse, it is difficult to make generalizations about them. However, a few things are true almost all of the time. For instance, most contain herbivores that eat plants (that get their sustenance from the sun and the soil) and all have carnivores that eat herbivores and other carnivores. Some places, such the poles, contain mainly carnivores because not plant life grows. A lot of animals and plants that grow and live in terrestrial ecosystems also interact with freshwater and sometimes even ocean ecosystems.

Ocean Ecosystems

Ocean ecosystems are relatively contained, although they, like freshwater ecosystems, also include certain birds that hunt for fish and insects close to the ocean’s surface. There are different sorts of ocean ecosystems: ●

Shallow water – Some tiny fish and coral only live in the shallow waters close to land.

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Deep water – Big and even gigantic creatures can live deep in the waters of the oceans. Some of the strangest creatures in the world live right at the bottom of the sea.

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Warm water – Warmer waters, such as those of the Pacific Ocean, contain some of the most impressive and intricate ecosystems in the world.

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Cold water – Less diverse, cold waters still support relatively complex ecosystems. Plankton usually forms the base of the food chain, following by small fish that are either eaten by bigger fish or by other creatures such as seals or penguins.

Environment Components: The term environment is drawn from French language which means surroundings. As such it is being defined as the surroundings in which an organism lives, including air, water, land, natural resources, flora, fauna, humans, and their interrelations. This definition extends the view from the focus of an organism to the global system. The study of such environment (all systems of air, land, water and energy systems in relation to life systems) is called environmental studies& the relevant branch is called environmental science(s). Through various studies related to environment (environmental studies) we could understand & realize that our environment is getting degraded due to increasing population coupled with unplanned technological revolutions,

pollution, toxification, acidification,

desertification, deforestation, loss of biodiversity, global warming, depletion of ozone layer, resource depletion, etc. making life miserable. This necessitated a need to incorporate an environmental concern in our technological inventions and innovations to eliminate or at least minimize their adverse impact on the environment. Such part of the technology is called

‘environmental technology’ which can be defined as the development of technology to combat adverse effects on environment. Components: There are two types of components of environment. 1. Non-living physical components of the environment which comprise the Atmosphere (air), Hydrosphere (water) and Lithosphere (land). 2. Living or biological component is biosphere which includes plants, animals and other organisms. The environment of an organism therefore, includes (i) Atmosphere, (ii) Hydrosphere, (iii) Lithosphere and (iv)Biosphere.

Atmosphere

Lithosphere Biosphere

Hydrosphere

Atmosphere: An atmosphere is a layer of gases that may surround the earth. Importance of atmosphere: The atmosphere protects life on Earth by absorbing ultravioletsolar radiation, warming the surface through heat retention (greenhouse effect), and reducing temperature extremes between day and night (the diurnal temperature variation). It contains oxygen and carbon dioxide used in breathing and photosynthesis – vital bioprocesses. The Atmosphere is a prime mean for the spatial diffusion of pollutants and a temporary mean of their accumulation. Composition of Earth’s atmosphere: Dry air contains roughly (by volume) 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.039% carbon dioxide, and small amounts of other gases. Air

also contains a variable amount of water vapor, on average around 1%. Although the atmosphere is approximately 1,100 km high, the stratosphere (10 to 50 km) and the Troposphere (less than 10 km) are the main Atmospheric interactors of the Biosphere. Structure of Atmosphere: The atmosphere consists of almost concentric layers of air with varying density and temperature. Density is highest on the earth’s surface and decreases rapidly upwards. In the atmosphere, broadly five layers can be identified. They are, ●

Troposphere: from the surface to 8km (near the poles) to 18 km (near the equator). o

Tropo means change or turning which refers to the action of the winds which keeps the troposphere in constant motion. Almost all changes in our daily weather occur in this layer of atmosphere.

●

o

Air temperature in this sphere gradually decreases with height.

o

Important zone for organisms and is composed of different gases.

Stratosphere: from that 18 km range to about 50 km, o

Temperature rises with increase in height (from a minimum of about -550C to a minimum of 50C).

●

o

It has no clouds ,dust or water vapours

o

It is rich in ozone, which absorbs harmful UV radiations from the sun.

Mesosphere: from about 50 km to the range of 80 km to 85 km.

●

o

Temperature decreases with height.

o

It is characterized by low temperature with low pressure

o

It has various gases like N2, O2+, NO+

Thermosphere or Ionosphere: from 80–85 km to 640+ km. o

Temperature increasing with height

o

Most of the gaseous components such as O2, O+, NO+ are ionized under the influence of radiant energy and so contains electrically charged particles.

o

These particles reflect radio waves back to the earth surface and enable us to have wireless communications.

●

Exosphere: above the ionosphere, where the atmosphere thins out into space

The boundaries between these regions are named the Tropopause, Stratopause and Mesopause.

(The structure of the atmosphere.) Ozone layer or ozonosphere is found in stratosphere, approximately at 10 - 50 km height. The average temperature of the atmosphere at the surface of earth is 14 °C.

The lithosphere:

The Earth is made of Earth’s Crust, Mantle and the Core. In the centre of the earth is the core which, is surrounded by the mantle. Lithosphere is the thin crust between the mantle and the atmosphere. Together the crust and upper mantle are called the lithosphere and extends upto a depth of about 80 -100 km. Earth’s crust: The crust, the outermost layer, is rigid and very thin compared with the other two. Beneath the oceans, the crust varies little in thickness, generally extending only to about 5 km. The thickness of the crust beneath continents is much more variable but averages about 30 km. Earth’s mantle: Below the crust is the mantle, a dense, hot layer of semi-solid rock approximately 2,900 km thick. The mantle, which contains more iron, magnesium, and calcium than the crust, is hotter and denser because temperature and pressure inside the Earth increase with depth. Earth’s core: Is nearly twice as dense as the mantle because its composition is metallic (ironnickel alloy) rather than stony. It is actually made up of two distinct parts: a 2,200 km-thick liquid outer core and a 1,250 km-thick solid inner core. As the Earth rotates, the liquid outer core spins, creating the Earth's magnetic field.

Asthenosphere: At least 80 km in thickness over much of the Earth, the lithosphere has been broken up into the moving plates that contain the world's continents and oceans. Below the lithosphere is a relatively narrow, mobile zone in the mantle called the Asthenosphere (from

asthenes, Greek for weak). This zone is composed of hot, semi-solid material, which can soften and flow after being subjected to high temperature and pressure over geologic time. The rigid lithosphere is thought to "float" or move about on the slowly flowing Asthenosphere. Although the lithosphere is around 100 km thick, only 1 km of it can be considered in interaction with the biosphere. Main constituents are oxygen (47%), silicon (28%), aluminum (8%), iron (5%), calcium (4%), sodium (3%), potassium (3%) and magnesium (2%) in a crystalline state. The lithosphere is the main source of pollutants and a permanent accumulator. Some are naturally released through sources like volcanic eruptions, while others like fossil fuels are the result of artificial extraction and combustion.

Hydrosphere: The planetary water supply is dominated by the oceans (see Table 8b-1). Approximately 97% of all the water on the Earth is in the oceans. The other 3% is held as freshwater in glaciers and icecaps, groundwater, lakes, soil, the atmosphere, and within life.

Water moves from one reservoir to another by way of processes like evaporation, condensation, precipitation, deposition, runoff, infiltration, sublimation, transpiration, melting, and groundwater flow. The oceans supply most of the evaporated water found in the atmosphere. Of this evaporated water, only 91% of it is returned to the ocean basins by way of precipitation. The remaining 9% is transported to areas over landmasses where climatologically factors induce the formation of precipitation. The resulting imbalance between rates of evaporation and precipitation over land and ocean is corrected by runoff and groundwater flow to the oceans.

Reservoir

Percent of Total

Oceans

97.25

Ice Caps and Glaciers

2.05

Groundwater

0.68

Lakes

0.01

Soil Moisture

0.005

Atmosphere

0.001i

Streams and Rivers

0.0001

Biosphere

0.00004

The Biosphere: The term "Biosphere" was coined by geologist Eduard Suess in 1875, which he defined as the place on earth's surface where life dwells. The biosphere is the part of the earth including air, land, surface rocks and water within which life occurs. From the broadest biophysiological point of view, the biosphere is the global ecological system integrating all living beings and their relationships, including their interaction with the elements of the lithosphere, hydrosphere, and atmosphere. This biosphere is postulated to have evolved, beginning through a process of biogenesis or biopoesis, at least some 3.5 billion years ago. Biomass accounts for about 3.7 kg carbon per square meter of the earth's surface averaged over land and sea, making a total of about 1900 gigatonnes of carbon. The biosphere is structured into a hierarchy known as the food chain whereby all life is dependent upon the first tier (i.e. mainly the primary producers that are capable of photosynthesis). Energy and mass is transferred from one level of the food chain to the next with an efficiency of about 10%. The biosphere can be divided into distinct ecosystems that represent the interactions between a group of organisms forming a tropic pyramid and the environment or habitat in which they live. Environmental education: Environmental education (EE) refers to organized efforts to teach how natural environments function, and particularly, how human beings can manage behaviour and ecosystems to live sustainably. It is a multi-disciplinary field integrating disciplines such as biology, chemistry, physics, ecology, earth science, atmospheric science, mathematics, and geography. The term often implies education within the school system, from primary to post-secondary. However, it sometimes includes all efforts to educate the public and other audiences, including print materials, websites, media campaigns, etc.,

Environmental Education (EE) is the teaching of individuals, and communities, in transitioning to a society that is knowledgeable of the environment and its associated problems, aware of the solutions to these problems, and motivated to solve those. The United Nations Educational, Scientific and Cultural Organization (UNESCO) states that EE is vital in imparting an inherent respect

for

nature

amongst

society

and

in

enhancing

public

environmental

awareness. UNESCO emphasizes the role of EE in safeguarding future global developments of societal quality of life (QOL), through the protection of the environment, eradication of poverty, minimization of inequalities and insurance of sustainable development (UNESCO, 2014a). Environmental education focuses on: 1. Engaging with citizens of all demographics to; 2. Think critically, ethically, and creatively when evaluating environmental issues; 3. Make educated judgments about those environmental issues; 4. Develop skills and a commitment to act independently and collectively to sustain and enhance the environment; and, 5. To enhance their appreciation of the environment; resulting in positive environmental behavioral change. ENVIRONMENTAL LAW and Regulations ‘Environmental Law’ is an instrument to protect and improve the environment and to control or prevent any act or omission polluting or likely to pollute the environment. An environmental legal system is essentially a set of laws and administrative rules which regulate the relationships and conflicts between all the people concerned with the environment, as well as defining the relationships between people and the environment itself. In the Constitution of India, it is clearly stated that it is the duty of the State

to “protect and

improve the environment and to safeguard the forests and wildlife of the country”. It imposes a duty on every citizen “to protect and improve the natural environment including forests, lakes, rivers, and wildlife”. Reference to the environment has also been made in the Directive Principles of State Policy (Part IV) as well as the Fundamental Rights (Part III). The Department of Environment was established in India in 1980 to ensure a healthy environment

for the country. This later became the Ministry of Environment and Forests in 1985. Ministry of Environment and Forests (MoEF) The Ministry of Environment & Forests (MoEF) is the nodal agency in the administrative structure of the Central Government for planning, promotion, co- ordination and overseeing the implementation of India’s environmental and forestry policies and programmes. The primary concerns of the Ministry are implementation of policies and programmes relating to conservation of the country’s natural resources including its lakes, rivers, biodiversity, forests and wildlife, ensuring the welfare of animals, and the prevention and abatement of pollution. The broad objectives of the Ministry are: ●

Prevention and control of pollution;

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Protection of the environment; and

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Ensuring the welfare of plants & animals

The Water (Prevention and Control of Pollution) Act, 1974 The Water (Prevention and Control of Pollution) Act was enacted in 1974 to provide for the prevention and control of water pollution, and for maintaining or restoring of wholesomeness of water in thecountry. This is the first law passed in India whose objective was to ensure that the domestic and industrial pollutants are not discharged into rivers, and lakes without adequate treatment. The reason is that such a discharge renders the water unsuitable as a source of drinking water as well as for the purposes of irrigation and support marine life. In order to achieve its objectives, the Pollution Control Boards at Central and State levels were created to establish and enforce standards for factories discharging pollutants into water bodies.

The Air (Prevention and Control of Pollution) Act, 1981 The Air (Prevention and Control of Pollution) Act, 1981 was enacted to provide for the prevention, control and abatement of air pollution in India. It is a specialized piece of

legislation which was enacted to take appropriate steps for the preservation of natural resources of the earth, which among other things include the preservation of the quality of air and control of air pollution. The prime objectives of the Act are the following: •

Prevention, control and abatement of air pollution;

•

Establishment of central and state pollution control boards to implement the aforesaid purpose; and

•

To maintain the quality of air. The Environment Protection Act, 1986

It was the Bhopal Gas Tragedy which necessitated the Government of India

to enact a

comprehensive environmental legislation, including rules relating to storing, handling and use of hazardous waste. On the basis of these rules, the Indian Parliament enacted the Environment Protection Act, 1986. This is an umbrella legislation that consolidated the provisions of the Water (Prevention and Control of Pollution) Act of 1974 and the Air (Prevention and Control of Pollution) Act of 1981. Within this framework of the legislations, the government established Pollution Control Boards (PCBs) in order to prevent, control, and abate environmental pollution.The objective of the Environment Protection Act is to protect and improve the environment in the country. The Noise Pollution (Regulation and Control) Rules, 2000 There

was

no

direct

provision

for

‘noise

pollution’

under

the

Environment

ProtectionAct,1986oranyotherlegislation.Theincreasingambientnoiselevels inpublicplacesfromvarioussourceslikeindustrialactivity,generatorsets,loud speakers, vehicular horns etc. have harmful effects on human health. It wasthe need of the hour to come with a law which would regulate and control noise producing sounds with the objective of maintaining the ambient air quality standards in respect of noise. Therefore, the Central Government framed ‘The Noise Pollution (Regulation and Control) Rules, 2000’. These rules have been laid down by the government to reduce environmental noisepollution.Certainstandards,suchastheambientairqualitystandards,have

beensetbythegovernment.Thepermissiblelevelsofnoisearedifferentfordifferentareas,suchasindust rial,commercial,residentialareasandsilencezones (area within the vicinity of hospitals, educational institutions or courts). The National Environment Tribunal Act, 1995 This Act is aimed to provide for strict liability for damages arising out of any accident occurring while handling any hazardous substance and for the establishment of a National Environment Tribunal for effective and expedition disposal of cases arising from such accident, with a view to giving relief and compensation for damages to persons, property and the environment and for matters connected with it. The beauty of this Act lies in the fact that the liability of the owner of hazardous substance has been made strict in case of any accident and the resultant injury to public. In any claim for the compensation, the claimant is not required to plead and establish that the death, injury or damage in respect of which the claim has been made was due to any wrongful act, neglect or default of any person. So, the burden of proof does not rest upon the claimant of compensation which is a big relief for the victims.

The Central Pollution Control Board The Central Pollution Control Board (CPCB) a statutory organization was constituted in September, 1974 under the Water (Prevention and Control of Pollution) Act, 1974 to deal with the rise in pollution. Further, CPCB wasentrusted with the powers and functions under the Air (Prevention and Control of Pollution) Act,1981. Principal functions of the CPCB:to promote cleanliness of streams and wells in different areas of theStates by prevention, control and abatement of water pollution, andto improve the quality of air and to prevent, control or abate air pollution in the country.

Other Functions of the Central Board ●

Advise the Central Government on any matter concerning prevention and controlofwaterandairpollutionandimprovementofthequalityof air.

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Planandcausetobeexecutedanation-wideprogrammefortheprevention,

control

or

abatement of water and air pollution. ●

ProvidetechnicalassistanceandguidancetotheStateBoards,carryoutand

sponsor

investigation and research relating to problems of water and air pollution, and for their prevention, control or abatement. ●

Prepare manuals, codes and guidelines relating to treatment and disposalof sewage and trade effluents as well as for stack gas cleaning devices, stacks andducts.

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Lay down or modify (in consultation of the State Governments), the standards for streams or wells and lay down standards for the quality ofair.

Functions of State Boards ● To advise the State Government on matter relating to pollution and on ‘siting’ ofindustries; ● To plan programmes for pollutioncontrol; ● To collect and disseminateinformation; ● To carry out inspection of polluting industries and areas; ● To lay down effluent and emission standards; and ● To issue consent to industries and other activities for compliance of prescribed emission and effluentstandards

Global Environmental Issues: ACID RAIN Acid rain is rain or any other form of precipitation that is unusually excessive acidic. Acid rain is infact a cocktail of mainly sulfuric acid (60 to 70 %) & nitric acid (30 to 40 %) with a little

hydrochloric acid. This acidification of rain is a natural phenomenon, where the atmospheric carbon dioxide reacts with water to form carbonic acids to make this natural rain water slightly acidic (pH- 5.6). However, during recent years, due to increased anthropogenic activities, like industrialization, transportation, urbanization, use of fossil fuels, etc. the atmospheric concentration of sulphur dioxide, oxides of nitrogen, chlorides, etc. has increased enormously. These constituents react with water to form their respective acids. These acids reduces the pH of the rain water, some time to as low as that of lemon juice (pH- 2.2). Effects: 1. Acid rain causes acidification of lakes and streams and contributes 2. It damages the vegetation by wearing away the waxy protective coating of leaves, damaging them and preventing them from being able to photosynthesize properly 3. Dissolve and wash away the nutrients and minerals in the soil & making it unfertile 4. In addition, acid rain accelerates the decay of building materials and paints, including irreplaceable buildings, statues, and sculptures (corrosion) that are part of our nation's cultural heritage. 5. Prior to falling to the earth, sulfur dioxide (SO2) and nitrogen oxide (NOx) gases and their particulate matter derivatives—sulfates and nitrates—contribute to visibility degradation and harm public health. Control: 1. Reduce emissions 2. Find alternative sources of energy 3. Restoring the Damage done by Acid Rain http://www.epa.gov/acidrain/effects/index.html Environmental chemistry: BK Sharma & H KAUR Ozone depletion Ozone is an unstable blue gas having pungent odour. Chemically, it is an allotrope of Oxygen which is an element in the gaseous form. It has three oxygen atoms in its single molecule and in

the language of Chemistry; its molecular formula is 03. It is used as a powerful oxidant, bleach, and water purifier. It is also used to treat industrial wastes. Where is ozone found? If found in the troposphere; ozone acts as a powerful pollutant. But, when found in the stratosphere, it acts like a friend of the earth because it shields most of the ultra violet radiations and does not allow them to pass on towards the same. In stratosphere, it is found in the form of a dense layer called as the Ozone Layer or the Ozone Belt. Thus, the Ozone Belt in the stratosphere acts like a Protective Umbrella of the earth. Let us see, how this gas is formed in the atmosphere. How is ozone formed? Ozone is formed in the stratosphere when oxygen molecules Photo dissociate after absorbing an UV Photon of shorter wavelength(less than 240 nm) to produce two oxygen atoms. Ozone is mainly produced from oxygen containing molecules such as Sulphur dioxide, Nitrogen Oxides, etc. also when these molecules are exposed to ultraviolet radiations. In Chemistry, a molecule is the particle of any substance that can remain in a free state. But, what is an atom? Well, an atom is the smallest particle of a substance that cannot usually remain in a free condition. Two or more atoms combine to form a molecule. Through the foregoing lines, we came across another term, allotrope. One of the two or more different forms of molecules of an element is called as an allotrope. A large number of ozone molecules assemble around the earth to form the Ozone Layer which extends from 13 to 48 km above the earth surface. On an average, it is about 230 Dobson units (DU) in thickness. DU is the unit which measures thickness of the ozone layer. It equals to 0.01 mm.

Ozone depleting substances Chlorofluorocarbons (CFCs or Freons), Methane, Nitrous Oxides (N2O), Carbon Tetrachloride (CCl4), Methyl Bromide (a soil fumigant and insecticide), aircraft emissions, n- propyl bromide and Halon- 1202 are major agents that cause depletion of ozone layer. Hence, these are called as Ozone Depleting Substances (ODS).

How is the Ozone Layer Depleted? Chlorofluorocarbons or Freons get accumulated in greater amounts at high altitudes and gradually reach to the stratosphere. Under the influence of intense short wave ultraviolet radiations they release chlorine atoms. A single chlorine atom can react with more than, 100,000 molecules of ozone and can convert them into oxygen. Other ozone depleting substances like methane, nitrous oxide, methyl bromide etc. too, pass through a series of reactions under the influence of UV-radiations of sunlight and catalysts found in the air and help in the depletion of ozone layer. • Ozone molecule absorbs UV light between 310 and 200 nm. The ozone molecule absorbs oxygen atom to form two molecules of Oxygen, and the Ozone cycle continues. • Ozone is destroyed by a number of free radicals catalysts –like Hydroxyl radical, Nitric oxide radical, and Bromine through natural and anthropogenic sources. Effects of the Depletion of Ozone Layer I. General Effects Ozone absorbs ultraviolet radiations so that much of it is never allowed to reach to the earth surface. The protective umbrella of ozone layer in the stratosphere protects the earth from harmful ultraviolet radiations. Ozone plays an important role in the biology and climatology on the earth’s environment. It filters out all the radiations that remain below 3000Å. Radiations below this wavelength are biologically harmful. Hence any depletion of ozone layer is sure to exert catastrophic impacts on life in the biosphere. The Ultraviolet radiation is one of the most harmful radiations contained in the sunlight. Ozone layer in the stratosphere absorbs these radiations and does not allow it to reach to the earth. The depletion of Ozone layer may lead to UV exposures that may cause a number of biological consequences like Skin Cancer, damages to vegetation, and even the reduction of the population of planktons (in the oceanic Photic zone). Some of the remarkable effects of the UV radiations or the effects of depletion of the Ozone Layer are mentioned below. (1) UV radiation causes sun- eye- diseases (cataract), skin diseases, skin cancer and damage to immune system in our body. (2) It damages plants and causes reduction in crop productivity.

(3) It damages embryos of fish, shrimps, crabs and amphibians. The population of salamanders is reducing due to UV-radiations reaching to the earth. (4) UV- radiations damage fabrics, pipes, paints, and other non-living materials on this earth. (5) It contributes in the Global Warming. If the ozone depletion continues, the temperature around the world may rise even up to 5.5 Celsius degrees. II.Specific Effects The specific effects of depletion of Ozone Layer have been observed on Human Society, Agriculture, Plants and Animals etc. These effects have been summarized as belowA. Effects of Ozone Depletion on Human Society (i).The flux of ultra violet radiation in the biosphere is increased due to ozone depletion. It has seriously harmful effects on human societies like formation of patches on skin and weakening of the human immune system. (ii). It may cause three types of skin cancer like basal cell carcinoma, squamous cell carcinoma and melanoma. A 10 per cent decrease in stratospheric ozone has been reported to cause 20 to 30 per cent increase in cancer in human society. Each year, about 7000 people die of such diseases each year in USA. About 10 percent increase in skin cancer has been reported in Australia and New Zealand. (iii).Exposure to UV radiations damages skin of the sun-bathing people by damaging melanocyte-cells or by causing sun-burns due to faster flow of blood in the capillaries of exposed areas. (iv).Exposure to UV radiations due to ozone depletion may cause leukemia and breast cancer. (iv).Exposure of UV radiation to human eye damages cornea and lens leading to Photo keratitis, cataract and even blindness. (v).The Ambient Ozone Exposure may cause Emphysema, bronchitis, asthma and even obstruction of lungs in human beings. (vi).Exposure to radiations due to ozone depletion has been reported to cause DNA breakage, inhibition and alteration of DNA replication and premature ageing in human beings. Effect of Ozone Depletion on Agriculture

(i). Radiations reaching to the earth due to ozone depletion cause severe damage to plants including crops. As per reports, ultra violet radiations reaching to the earth cause losses up to 50 per cent in European countries. (ii).The radiation reaching to the earth due to the depletion of the ozone layer cause visible damages in plants. They adversely affect the rate of photosynthesis that finally results into decrease in the agricultural production. (iv).The UV radiation enhances the rate of evaporation through stomata and decreases the moisture content of the soil. This condition adversely affects the growth and development of crop plants and reduces the crop yield. (v). The ozone reduction adversely affects the weather pattern which in turn affects the crop production by encouraging plant injuries and disease development. (vi). The UV radiation reaching to the earth surface alters the global balance between radiation and energy. This condition of imbalance causes seasonal variations that further reduce the crop production. (vii). A number of economically important plant species such as rice, depend on cyanobacteria residing in their roots for the retention of nitrogen. These bacteria are sensitive to UV light and they are hence, are killed instantly. C. Effects of Ozone Depletion on other Plants and Animals (i).The ozone layer depletion causes climatic alterations that cause physiological changes in plants and animals. The change in the energy balance and radiation may affect the survival and stability of living organisms. (ii).The depletion of ozone layer may cause changes in thermal conditions of the biosphere. It may affect type, density and stability of vegetation which in turn may affect different bio-geochemical cycles operating in nature. Interruption in these cycles damages important process of ecosystem leading to dangerous conditions for plants and animals. (iii).The depletion of ozone layer causes death of plankton- populations in fresh as well as marine waters .This condition seriously affects the transfer of materials in ecosystems. The recent researches gave analyzed a widespread extinction of planktons 2 million years ago that coincided with the nearby supernova. Planktons are particularly susceptible to effects of UV light and are vitally important to the marine food webs.

The Ozone Hole The hole in the context of ozone depletion relates to thinning of the ozone layer in a certain area. Here, the word hole is considered as a hole in the ground which in the context of ozone layer is thinning of ozone in a certain area up to certain depth as measured by scientists. In fact, ozone hole is an area where the ozone concentration drops to an average of about 100 Dobson Units. The word ‘Dobson’ has been taken from the name of the famous scientist and climatologist G. M. B. Dobson, who observed the ozone hole for the first time in 1956, over Halley Bay. The satellite measurements done in September 2000 revealed that the thinning of ozone layer in Antarctic had reached a record 28.3 million sq km which was about one million sq km greater than the record of 1998. Thinning of ozone in such a big area is rightly termed as ozone hole. The ozone hole in the Northern Latitudes has also been recorded. The ozone hole over Antarctica may expose not only the Antarctica but also a large area of the pacific and Atlantic oceans and South America as well. The ozone hole over Antarctica was first discovered by Farman, Gardiner and Shanklin in 1985. They jointly declared their findings through a paper published in the May issue of Nature (an important International Journal) in 1985. The entire scientific community was shocked to know their findings. On the basis of observations made through a network of ground based Dobson Spectrophotometer, an International Panel of scientists confirmed that the Ozone Layer was being depleted at all latitudes outside the tropics. Out of a big group of scientists across the world, Crutzen, Molina, and Rowland were awarded the Nobel Prize in Chemistry for their work on Stratospheric Ozone, in 1995.The scientific assessment of ozone depletion is going on across the world since 1981, under the sponsorship of the United Nations Environment Programme (UNEP), and the most recent measurement was done during the year 2006. Here are the comparative pictures showing the Ozone Holes over Antarctica during the spring seasons of two different years. The General Assembly of the United Nations voted to designate September 16 as the World Ozone Day, to mark the signing of the Montreal Protocol, the 16th September, 1987.By December 2001, 182 countries ratified the Vienna Convention and 181 the Montreal Protocol. By 2000, 96 chemicals were subject to control under the Montreal Protocol.

Global warming: Global warming, also referred to as climate change, is the observed century-scale rise in the average temperature of the Earth's climate system and its related effects.Multiple lines of scientific evidence show that the climate system is warming.Many of the observed changes since the 1950s are unprecedented in the instrumental

temperature

record which

extends

back

to

the

mid-19th

century,

and

in paleoclimate proxy records covering thousands of years. In 2013, the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report concluded that "It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century." The largest human influence has been the emission of greenhouse gases such as carbon dioxide, methane and nitrous oxide. Model projections summarized in the report indicated that during the 21st century, the global surface temperature is likely to rise a further 0.3 to 1.7 °C (0.5 to 3.1 °F) in the lowest emissions scenario, and 2.6 to 4.8 °C (4.7 to 8.6 °F) in the highest emissions scenario. These findings have been recognized by the national science academies of the major industrialized nationsand are not disputed by any scientific body of national or international standing.

But climate scientists looking at the data and facts agree the planet is warming. While many view the effects of global warming to be more substantial and more rapidly occurring than others do, the scientific consensus on climatic changes related to global warming is that the average temperature of the Earth has risen between 0.4 and 0.8 °C over the past 100 years. The increased volumes of carbon dioxide and other greenhouse gases released by the burning of fossil fuels, land clearing, agriculture, and other human activities, are believed to be the primary sources of the global warming that has occurred over the past 50 years. Scientists from the Intergovernmental Panel on Climate carrying out global warming research have recently predicted that average global temperatures could increase between 1.4 and 5.8 °C by the year 2100. Changes resulting from global warming may include rising sea levels due to the melting of the polar ice caps, as well as an increase in occurrence and severity of storms and other severe weather events. Future climate change and associated impacts will differ from region to region around the globe.Anticipated effects

include

warming

global

temperature, rising

sea

levels,

changing precipitation, and expansion of deserts in the subtropics.[15]Warming is expected to be greater over land than over the oceans and greatest in the Arctic, with the continuing retreat of

glaciers, permafrost and sea ice. Other likely changes include more frequent extreme weather events such as heat waves, droughts, heavy rainfall with floods and heavy snowfall; ocean acidification; and species extinctions due to shifting temperature regimes. Effects significant to humans include the threat to food security from decreasing crop yields and the abandonment of populated areas due to rising sea levels.Because the climate system has a large "inertia" and greenhouse gases will remain in the atmosphere for a long time, many of these effects will persist for not only decades or centuries, but for tens of thousands of years to come. Possible

societal

responses

to

global

warming

include mitigation by

emissions

reduction, adaptation to its effects, building systems resilient to its effects, and possible future climate engineering. Most countries are parties to the United Nations Framework Convention on Climate Change (UNFCCC), whose ultimate objective is to prevent dangerous anthropogenic climate change.[21] Parties to the UNFCCC have agreed that deep cuts in emissions are required and that global warming should be limited to well below 2.0 °C (3.6 °F) compared to pre-industrial levels, with efforts made to limit warming to 1.5 °C (2.7 °F). Public reactions to global warming and concern about its effects are also increasing. A global 2015 Centre report showed that a median of 54% of all respondents asked consider it "a very serious problem". Significant regional differences exist, with Americans and Chinese (whose economies are responsible for the greatest annual CO2 emissions) among the least concerned. ISO 14000: Environmental Management System Standards: ISO (International Organization for Standardization), headquartered in Geneva, is a worldwide federation of national standards bodies from each country. The object of ISO is to promote the development of standardization and related activities in the world with a view to facilitating international exchange of goods and services, and to developing cooperation in the spheres of intellectual, scientific, technological and economic activity. The results of ISO technical work are published as International Standards. ISO 14000 is a series of environmental management standards developed and published by the International Organization for Standardization (ISO) for organizations. The ISO 14000 standards provide a guideline or framework for organizations that need to systematize and improve their

environmental management efforts. The Technical Committee (TC) number 207 (ISO/TC 207), and its Sub-committees of ISO are responsible for the development of ISO 14000 standards. The ISO 14000 family includes most notably the ISO 14001 standard, which represents the core set of standards used by organizations for designing and implementing an effective Environmental Management System (EMS). Other standards included in this series are ISO 14004, which gives additional guidelines for a good EMS, and more specialized standards dealing with specific aspects of environmental management.

ISO 14001 is suitable for organizations of all types and sizes, be they private, not-for-profit or governmental. An organization may implement its environmental management system (EMS) by following the principles/elements of ISO14001 as follows. Principles of ISO 14001 These are based on the well-known ‘Plan-Do-Check-Act’ cycle with an emphasis on having an environmental policy & achieving continual improvement. 1. Environmental policy: Define relevant environmental policy taking into account the organization’s activities & its interests. 2. Plan: Review the organization’s activities & its interests to identify all "environmental aspects". It requires that an organization considers all environmental issues relevant to its operations, such as air pollution, water and sewage issues, waste management, soil contamination, climate change mitigation and adaptation, and resource use and efficiency. Taking these environmental aspects into account, establish SMART environmental objectives, goals, and targets. Establish documented control procedures to carry out the activities. 3. Do: Implement documented control procedures to carry out the activities so that the "environmental aspects" can be properly controlled through active participation across all levels of the organization to achieve improvement in environmental performance. 4. Check: Monitor & measure the performance periodically, to ensure the environmental targets and objectives are being met. 5. Act: A top level review of performance to be conducted to ensure that the objectives are being met & to achieve continual improvement.

The organizations can gain benefits by implementing EMS as per ISO 14001. Such EMS may even get certification to ISO 14001 by Accredited Certification Agencies. Through certification, the organization can project as ISO 14001 certified, thereby it can demonstrate to the buyers, customers, suppliers and other stakeholders that it has implemented the standard properly. What’s more, for some organizations, it helps to show how they meet regulatory or contractual requirements. Benefits of ISO 14001 There are many reasons why an organization should take a strategic approach to improving its environmental performance. Users of the standard have reported that ISO 14001 helps: ●

Identify cost savings with greater emphasis on resource, waste and energy management.

●

Improve company reputation and the confidence of stakeholders through strategic communication

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Quantify, monitor and control the impact of operations on the environment, now and in the future.

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Ensure legislative awareness and compliance.

●

Increase leadership involvement and engagement of employees

Environmental Impact Assessment: Defining EIA An environmental impact assessment is an assessment of the possible positive or negative, whole or partial impact that a proposed project or an element of an organization’s activities or products or services, may have on the environment, together consisting of the natural, social and economic aspects. It is an exercise to document the consequences of a proposed project in totality along with measures necessary to keep the environment clean and healthy.

Why we need EIA? (Objectives) ➢ The need to foresee the problems of a development project is the primary objective of Environmental Impact Assessment (EIA). ➢ Helps an organization to identify aspects and evaluate impacts on various components of environment and to determine the significance of the impact. ➢ Helps an organization to establish, implement, maintain and continuously improve its environmental policy and objectives and to improve environmental performance. ➢ Provides for sustainable development ➢ Helps policy makers to evaluate the project’s environmental consequences and make decisions: whether to go ahead with the project or to curb/restrain activities. ➢ Works as a tool for identifying applicable environmental legislation and comply with them (The Environment (Protection) Act, 1986) ➢ Works as a tool to enhance assurance and satisfaction of interested parties: investors, customers, employee, etc.

The EIA report must be prepared by incorporation of data during all the four seasons of the year. Such an EIA is termed a “comprehensive EIA”. However, there is provision for a single season collection of data, but this should not be done during the monsoon season. Such an EIA reports is termed a “Rapid EIA”.