ENVIRONMENTAL POLLUTION

 

 

Any unwanted change in the environment that causes damage or destruction is considered pollution. Pollution is defined as ‘an addition or excessive addition of certain materials to the physical environment (water, air and lands), making it less fit or unfit for life.’

 

1. Pollutants

• Pollutants are the materials or factors, which cause adverse on the natural quality of any component of the environment.
• For example, smoke from industries and automobiles, chemicals from factories, radioactive substances from nuclear plants, sewage of houses and discarded household articles are the common pollutants.

Classifications

According to the form in which they persist after release into the environment :

• Primary pollutants- These persist in the form in which they are added to the environment. Example: DDT, plastic.
• Secondary pollutants- These are formed by the interaction of nitrogen oxides and hydrocarbons. Example: peroxy acetyl nitrate (PAN) is formed by the interaction of nitrogen oxides and hydrocarbons.

According to their existence in nature :

• Quantitative pollutants- These occur in nature and become when their concentration reaches beyond a threshold level. Examples: carbon dioxide, and nitrogen oxides.
• Qualitative pollutants- These do not occur in nature and are man-made. Examples: fungicides, herbicides, DDT etc.,

According to their nature of disposal :

• Biodegradable pollutants - Waste products, which are not decomposed by microbial action. Example: sewage.
• Non-Biodegradable pollutants- Pollutants, which are not decomposed by microbial action. Examples: plastics, glass, DDT, salts of heavy metals, radioactive materials etc,

According to their origin:

• Natural
• Anthropogenic

Causes of pollution

• Uncontrolled growth in human population
• Rapid industrialization
• Urbanization
• Uncontrolled exploitation of nature
• Forest fires, radioactivity, volcanic eruptions, strong winds etc,

 

2. Air Pollution

• Air pollution is aggravated because of four developments: increasing traffic, growing cities, rapid economic development, and industrialization.
• The presence of one or more contaminants in the atmosphere, in such quality and for such duration as it is injurious or tends to be injurious to human health or the welfare of animal or plant life.
• It is the contamination of air by the discharge of harmful substances.
• Air pollution can cause health problems, damage the environment, property and climate change.

Major Air Pollutants-

Carbon Monoxide (CO)

• It is a colourless, odourless Guess that is produced by the incomplete burning of carbon-based fuels including petrol, diesel and wood.
• It is also produced from the combustion of natural and synthetic products like cigarettes.
• It closes the amount of oxygen that enters our blood.
• It can slow our reflexes and make us confused and sleepy.

Carbon Dioxide (CO₂): It is the principal greenhouse gas emitted as a result of human activities like the burning of coal, oil and natural gases.

Chlorofloro Carbons (CFC)

• These are gases that are released mainly from air conditioning systems and refrigeration.
• When released into the air, CFCs rise to the stratosphere, where to come in contact with a few other gases, which lead to a reduction of the ozone layer that protects the earth from the harmful ultraviolet rays of the sun.

Lead: It is present in petrol, diesel, lead batteries, paints, and hair dye products. Lead affects children in particular. It can cause nervous system damage and digestive problems in some cases cause cancer.

Ozone

• It occurs naturally in the upper layers of the atmosphere.
• This important gas Shields the earth from the harmful ultraviolet rays of the sun.
• However, at the ground level it is a pollutant with highly toxic effects.
• Vehicles and industries are the major source of ground-level ozone emissions.
• Ozone makes our eyes itch, burn and water. It lowers our resistance to colds and pneumonia.

Nitrogen Oxide: It causes smog and acid rain. It is produced from burning fuels including petrol, diesel and coal. Nitrogen oxide can make children susceptible to respiratory diseases in winter.

Suspended Particulate Matter (SPM): It consists of solids in the air in the form of smoke, dust and vapour that can remain suspended for extended periods and is also the main source of haze which reduces visibility. The finer particles, when breathed in can lodge in our lungs and cause lung damage and respiratory problems.

Sulphur Dioxide (SO₂): It is a gas produced from burning coal, mainly in thermal power plants. Some industrial processes, like the production of paper and the smelting of metals, produce sulfur dioxide. It is a major contributor to smog and acid rain. Sulfur dioxide can lead to lung diseases.

Smog: The term smog was first used in 1905 by Dr H A Des Voeux. Smog has been coined from a combination of the words smoke and fog. Smog is a condition of fog that has soot or smoke in it.

Formation of Somg 

• Photochemical smog is a term used to describe air pollution that is a result of the interaction of sunlight with certain chemicals in the atmosphere.
• One of the primary components of photochemical smog is ozone.
• While ozone in the stratosphere protects Earth from harmful UV radiation, ozone on the ground is hazardous to human health.
• Ground-level ozone is formed when vehicle emissions containing nitrogen oxides and volatile organic compounds interact in the presence of sunlight.
• Smog refers to hazy air that causes difficult breathing conditions.
• It is a combination of various gases with water vapour and dust.
• Its occurrence is often linked to heavy traffic, High temperatures, and calm winds. During the winter, wind speeds are low and cause the smoke and fog to stagnate near the ground, hence pollution levels can increase near ground level.
• Smoke particles trapped in the fog give it a yellow or black colour and this smog often settles over cities for many days.
• Ground-level ozone was formed through a complex reaction involving hydrocarbons, nitrogen oxides and sunlight.
• It is found when pollutants released from gasoline, diesel-powered vehicles and oil-based solvents react with heat and sunlight.

Effects of Smog

• It hampers visibility and harms the environment.
• Heavy smoke greatly decreases ultraviolet radiation.
• Heavy smoke results in the decrease of natural vitamin D production leading to a rise in the cases of rickets.
• Respiratory problems
• Bronchial diseases.

Indoor Air Pollution

• It refers to the physical, chemical and biological characteristics of air in the indoor environment within a home, an institution or a commercial facility.
• Indoor air problems can be subtle and do not always produce easily recognized impacts on health.
• Indoor air pollution is a concern where energy efficiency improvements sometimes make houses relatively airtight, reducing ventilation and rising pollutant levels.
• Different conditions are responsible for indoor air pollution in the rural areas and the urban areas.

Rural

• It is a rural area, that faces the greatest threat from indoor pollution, bad people rely on traditional fuels like firewood, charcoal and cow dung for cooking and heating.
• Burning such fuels produces large amounts of smoke and other air pollutants in the confined space of the home, resulting in high exposure. Women and children are the groups most vulnerable as they spend more time indoors and are exposed to smoke.
• Although many hundreds of separate chemical agents have been identified in the smoke from biofuels, the four most serious pollutants are particulates, carbon monoxide, polycyclic organic matter and formaldehyde.

Urban

• In urban areas, exposure to indoor air pollution has increased due to a variety of reasons-
• Construction of more tightly sealed buildings
• Reduced ventilation
• The use of synthetic materials for building and furnishing
• The use of chemical products, pesticides and household care products
• Indoor air pollution can begin within the building or drawn in from outdoors.
• Other than nitrogen dioxide, carbon monoxide and lead, several other pollutants affect the air quality.

Pollutants

Volatile organic compounds- The main indoor services are perfumes, hairsprays, Furniture Polish, glues, air fresheners, moth repellents, wood preservatives and other products. Health effects- irritation of the eye, nose and throat, headaches, nausea and loss of coordination. Long expected to damage the liver and other parts of the body.

Tobacco- Smoke generates a wide range of harmful chemicals and is carcinogenic. Health effects- burning eyes, nose and throat irritation to cancer, bronchitis, severe asthma and a decrease in lung function.

Biological pollutants- These include pollen from plants, mites and hair from pets, fungi, parasites and some bacteria. Most of them are allergens and can cause asthma, hay fever and other allergic diseases.

Formaldehyde- Mainly from carpets, particle boards and insulation foam. It irritates the eyes and nose and allergies.

Radon- It is a gas that is emitted naturally by the soil. Due to modern houses having poor ventilation, it is confined inside the house and causes lung cancers. Asbestos and pesticides are other air pollutants.

 

Fly Ash

• Ash is produced whenever the combustion of solid material takes place.
• Fly ash is one such residue which arises with the gases in the atmosphere. Fly ash is a very fine powder and tends to travel far in the air.
• The ash which does not rise is termed bottom ash.
• Nearly 73% of India’s total installed power generation capacity is thermal, of which 90% is coal-based generation, with diesel, wind, gas and steam making up the rest.

Composition

• Aluminium silicate
• Silicon dioxide
• Calcium oxide
• Fly ash particles are oxide-rich and consist of silica, alumina, oxides of iron, calcium and magnesium, and toxic heavy metals like lead, arsenic, cobalt and copper.
• Fly ash is generally captured by electrostatic precipitation or other particle filtration equipment before the flue gases reach the chimneys of coal-fired power plants.

Environmental Effects

• If fly ash is not captured and disposed of properly, it can pollute air and water considerably.
• It causes respiratory problems.
• Fly ash in the air slowly settles on leaves and crops in fields in areas near thermal power plants and lowers the plant yield.

Advantages

• Cement can be replaced by fly ash up to 35%, thus reducing the cost of construction, making roads, etc.
• Fly ash bricks are light in weight and offer high strength and durability.
• Fly ash is a better fill material for road embankments and concrete roads.
• Fly ash can be used in reclamation of wastelands.
• Abandoned mines can be filled up with fly ash.
• Fly ash can increase the crop yield and it also enhances water water-holding capacity of the land.

Policy Measures of MoEF 

• The Ministry of Environment and Forest vide its notification in 2009, has made it mandatory to use fly ash-based products in all construction projects, road embankment works and low-lying landfilling works within a 100 km radius of Thermal Power Stations.
• To use fly ash in mine filling activities within a 50 km radius of Thermal Power Stations.

 

Effects of Air Pollution

 

• Retard photosynthesis
• Sulphur dioxide causes chlorosis, plasmolysis, membrane damage, and metabolic inhibition.
• Hydrocarbons like ethylene cause premature leaf fall, fruit drop, shedding of floral buds, curling of petals and discolouration of sepals
• Ozone damages The chlorenchyma and thus destroys the foliage in a large number of plants.
• Effects on animals
• detoriationThe  of materials
• Aesthetic loss

Control Measures

• Policy measures
• Preventive measures like – selection of suitable fuel (fuel with low sulphur content) and its efficient utilization.
• Modifications in industrial processes or equipment to reduce emissions.
• Selection of suitable manufacturing site and zoning like setting of industries at a distance of residential areas, and installation of tall chimneys.
• Destroying the pollutants by thermal or catalytic combustion.
• Conversion of the pollutants to a less toxic form
• Collection of the pollutants

Different types of air pollutants can be eliminated/ minimized by following methods:

• Control of particulate matter- Two types of devices called arresters and scrubbers are used to remove particulate pollutants from the air.
• Arresters- These are used to separate particulate matter from contaminated air.
• Scrubbers- These are used to clean air for both dust and gases by passing it through dry or wet packing materials.
• Control of Gaseous pollutants- The gaseous pollutants can be controlled through the techniques of combustion, absorption and adsorption.
• Control of automobile exhaust-
• Use of efficient engines(multipoint fuel injection engine)
• Catalytic converter filters in vehicles can convert nitrogen oxide to nitrogen and reduce the potential hazards of NOx.
• Use of good quality automobile fuels
• Use of lead-free petrol
• Use of compressed natural gas. (CNG)

Government Initiatives

• National Air Quality Monitoring Program- In India, the Central Pollution Control Board (CPCB) has been executing a nationwide program of ambient air quality monitoring known as the National Air Quality Monitoring Program(NAMP). The NAMP is undertaken in India.
• To determine the status and trends of ambient air quality.
• To ascertain the compliance of NAAQS- National Ambient Air Quality Standards.
• To identify non-attainment cities
• To understand the natural process of cleaning in the atmosphere
• To undertake preventive and corrective measures.
• Annual average concentration of SOx levels is within the prescribed NAAQS.
• This reduction from earlier levels is due to various measures taken, including the use of CNG in public transport in Delhi, the reduction of sulphur in diesel and the use of LPG instead of coal as a domestic fuel.
• A mixed trend is observed in NO₂ levels due to various measures taken for vehicular pollution control, like stricter vehicular emission norms being partially offset by increased NOx levels due to the use of CNG in urban transport.
• Total suspended particulates, are still a matter of concern in several urban and semi-urban areas.

National Ambient Air Quality Standards (NAAQS):

• National Ambient Air Quality Standards were notified in the year 1982, and duly revised in 1994 based on health criteria and land uses.
• The NAAQS have been revisited and revised in November 2009 for 12 pollutants. They are :
• Sulphur dioxide (SO₂)
• Nitrogen dioxide (NO₂)
• Particulate matter having a size less than 10 microns (PM₁₀)
• Particulate matter having size less than 2.5 microns (PM₅)
• Ozone
• Lead
• Carbon monoxide(CO)
• Arsenic
• Nickel
• Benzene
• Ammonia
• Benzopyrene

National Air Quality Index

National Air Quality Index was launched by the Prime Minister in April 2015 starting with 14 cities to disseminate air quality information. The AQ1 has six categories of air quality, good, satisfactory, moderately polluted, poor, very poor and severe with distinct colour schemes. Each of these categories is associated with likely health impacts. AQ1 considers eight pollutants (PM₁₀, PM_2.5, NO₂, SO₂, CO, O₃, NH₃, Pb) for which National Ambient Air Quality Standards are prescribed.

Air Pollution in India

• India’s air pollution, ranked among the worst in the world is adversely impacting the lifespan of its citizens, reducing most Indian lives by over three years.
• Over half of India’s population-660 million people live in areas where fine particulate matter pollution is above India’s standards for what is considered safe “economic and political weekly.”
• A 2014 global analysis of how nations tackle environmental challenges has ranked India 155 among 177 nations and labelled the country’s air quality among the worst in the world.
• Of the world’s top 20 polluted cities, 13 are in India. Air pollution slashes life expectancy by 3.2 years for the 660 million Indians who live in cities.
• India is placed as the “bottom performer” on several; indicators like environmental health impact, air quality, water and sanitation and India’s environmental health severely lags behind the BRICS nations-Environmental Performance Index 2014.
• The Ganga and Yamuna are ranked among the world’s 10 most polluted rivers.
• Despite the directives of the National Green Tribunal, civic agencies continue to allow concretization in green belts. Booming real estate and demand for housing units are leading to a change in land use and shrinkage of natural conservation zones like forests, water bodies, wastelands, sanctuaries, and groundwater rechargeable areas.
• Mindless concretization of ground and green belts and booming real estate have led to the heat island effect, short wave radiations emanate from concrete surfaces at night time. Concretization prevents groundwater recharge thus depleting green cover. Tall buildings also block winds thereby reducing their cooling effect. Excessive concretization also leads to the weakening of trees.
• The environment crisis in India is many-sided and multi-faced which has to be addressed on different fronts and by a variety of different actors. We need to harness scientific and social-scientific expertise to develop and promote eco-friendly technologies in construction, energy, water management, industrial production and transportation. Scientific innovation needs to be complemented by legislative change as well as by changes in social behaviour.

Measures to control Delhi Air pollution

• The city needs an implemented strategy
• Reduce traffic and vehicles
• Scale up integrated public transport
• Cut dieselization
• Tax polluting modes
• Facilitate walking and cycling
• Decide to implement Bharat Stage IV nationwide in 2015 and Euro VI in 2020
• Put controls on other pollution sources.

 

3. Water pollution

• Water pollution is the contamination of water sources by substances which make the water unusable for drinking, cooking, cleaning, swimming and other activities.
• Addition of certain substances to the water like organic, inorganic, biological, radiological, heat which degrades the quality of water so that it becomes unfit for use.
• Water pollution is not only confined to surface water, but it has also spread to groundwater, sea and ocean.

Types of sources

• Point sources- It is directly attributable to one influence. Here pollutant travels directly from source to water. Point sources are easy to regulate.
• Diffuse or non-point sources- It is from various ill-defined and diffuse sources. They vary spatially and are difficult to regulate. The main sources of water pollution are as follows :
• Community wastewater - Include discharges from houses and commercial and industrial establishments connected to the public sewage systems. The sewage contains human and animal excreta, food residues, cleaning agents, detergents and other wastes.
• Industrial wastes - The industries discharge several inorganic and organic pollutants, which may prove highly toxic to living beings.

Putrescibility is the process of decomposition of organic matter present in water by microorganisms using oxygen.

• Fertilizers contain major plant nutrients like nitrogen, phosphorus and potassium.
• Excess fertilizers may reach the groundwater by leaching or may be mixed with surface water of rivers, lakes and ponds by runoff and drainage.
• Pesticides include insecticides, fungicides, herbicides, nematocides, soil fumigants, and rodenticides.
• They contain a wide range of chemicals like chlorinated hydrocarbons, organophosphates, metallic salts, carbonates, derivatives of acetic acid etc,
• Many of the pesticides are non-degradable and their residues have long life.
• animal excreta like dung, wastes from poultry farms, piggeries slaughter houses etc, reach the water through runoff and surface leaching during the rainy season.
• Thermal pollution- The main sources are the thermal and nuclear power plants. The power plants use water as a coolant and release hot water to the source. A sudden rise in temperature kills fish and other aquatic animals.
• Marine pollution - Oceans are the ultimate sink of all natural and man-made pollutants. Rivers discharge their pollutants into the sea. The sewage and garbage of coastal cities are also dumped into the sea. The other sources of oceanic pollution are navigational discharge of oil, grease, detergents, sewage, garbage and radioactive waste, offshore oil mining, and oil spills.

• Oil spills are one of the most dangerous of all water pollutants.
• Oil spills from tankers at sea or leaks from underground storage tanks on land are very difficult to control as oil tends to spread very fast, affecting a large area in a short time.
• On land crude is transported through pipelines or tankers which can get damaged and spew out crude oil over the land, thereby contaminating it.
• Since crude oil is lighter than water, it floats on the surface and poses the threat of swift-spreading fire.
• Oil spills at sea decrease the oxygen level in the water and cause harm to the organisms.
• Oil spills are also a source of air and groundwater pollution.
• Underground water pollution- The groundwater in many places in India, is threatened with contamination due to seepage from industrial and municipal wastes and effluents, sewage channels and agricultural runoff.

Effects of water pollution

• Polluted water reduces dissolved oxygen content, thereby eliminating sensitive Organisms like plankton, molluscs fish etc.
• A few tolerant species like tubifex-an annelid are inserted in highly polluted water with low DO content. Such species are recognized as indicators species for polluted water.
• Biocides, polychlorinated biphenyls(PCB)  And heavy metals directly eliminate sensitive aquatic organisms.
• Hot waters discharged from industries, when added to water bodies lower their DO content.
• The presence of organic and electronic waits in the hotel decreases the dissolved oxygen(DO) content of the water.
• Water with DO content below 8.0mg /L  is considered contaminated. Water having DO content below 4.0mg/L  is considered to be highly polluted.
• DO content of water is important for the survival of aquatic organisms. Factors like surface turbulence, photosynthetic activity, oxygen consumption by organisms and decomposition of organic matter are the factors which determine the amount of DO present in water.
• The higher amounts of waste increase the rates of decomposition and oxygen consumption, thereby decreasing the DO content of water. The oxygen demand is directly related to the increasing input of organic wastes and is considered the Biological Oxygen Demand of water(BOD).
• Water pollution by organic waste is measured in terms of biological oxygen demand(BOD). BOD is the amount of dissolved oxygen needed by bacteria to decompose the organic waste present in water. It is expressed in milligrams of oxygen per litre of water.
• The higher value of BOD indicates a low DO content of water. Since BOD  Is limited to biodegradable materials, It is not a reliable method of measuring pollution load in water.
• Chemical oxygen demand(COD) is the slightly better mode used to measure pollution load in the water. It is the measure of oxygen equivalent to the requirement of oxidation of total organic matter( biodegradable and non-biodegradable) present in water.
• The polluted water usually contains pathogens like viruses, bacteria,  parasitic protozoa, and worms.
• Therefore it is a source of waterborne diseases like jaundice, cholera, typhoid, amoebiasis etc.
• Mercury compounds in wastewater are converted by bacterial action into extremely toxic methyl mercury, which can cause numbness of limbs, lips and tongue, deafness, blurring of vision and mental derangement.
• A crippling deformity called  Minimata disease, is due to the consumption of fish captured from mercury-contaminated Minamata Bay in Japan was detected in 1952.
• Water contaminated with cadmium can cause Itai itai disease also called ouch-ouch disease (painful disease of bones and joints) and cancer of the lungs and liver.
• The compounds of lead cause anaemia, headache, loss of muscle power and a bluish line around the gum.

Hazards of groundwater pollution

• The presence of excess nitrate in drinking water is dangerous for human health and may be fatal for infants.
• Excess nitrate in drinking water reacts with haemoglobin and impairs oxygen transport. This condition is called methaemoglobin or blue baby syndrome.
• Excess fluoride in drinking water causes neuro-muscular disorders, gastrointestinal problems, teeth deformity, hardening of bones, and stiff and painful joints(skeletal fluorosis).
• High concentration of fluoride ions is present in drinking water in 13 states of India. The maximum level of fluoride, that the human body can tolerate is 1.5 parts per million(mg / L of water). Long-term ingestion of fluoride ions causes fluorosis.
• Over-exploitation of groundwater may lead to the leaching of arsenic from soil and rock sources and contaminate groundwater. Chronic exposure to arsenic causes black foot disease. It also causes diarrhoea, peripheral neuritis, hyperkeratosis and also lung, and skin cancer.
• Arsenic contamination is a serious problem in the Ganges Delta, West Bengal causing serious arsenic poisoning to large numbers of people.
• A 2007 study found that over 137 million people in more than 70 countries are probably affected by arsenic poisoning of drinking water.
• Biological magnification
• Eutrophication

 

Control measures

• Treatment of sewage water and industrial effluents should be done before releasing it into water bodies.
• Riparian buffers
• Hot water should be cooled before release from the power plants.
• Excessive use of fertilizers and pesticides should be avoided.
• Domestic cleaning in tanks, streams and rivers which supply drinking water, should be prohibited.
• Water hyacinth (aquatic weed) can purify water by taking some toxic materials and several heavy metals from water.
• Organic farming and efficient use of animal residues as fertilizers.
• Oil spills in water can be cleaned with the help of bigoli, a by-product of the paper industry resembling sawdust, oil zapper, and micro-organisms.

The steps taken by the government to address the issues of water pollution include the following:

• Installation of an Online Effluent Monitoring system to check the discharge of effluent directly into the rivers and water bodies.
• Preparation of an action plan for sewage management and restoration of water quality in aquatic resources by state governments.
• Setting up of monitoring network for assessment of water quality
• Financial assistance for the installation of Common Effluent Treatment Plants for a cluster of Small Scale Industrial units.
• Action to comply with effluent standards is taken by SPCBs/PCCs to improve the water quality of the rivers.
• Issuance of directions for implementation of Zero Liquid Discharge
• Issuance of directions under Section 5 of the Environment Protection Act, 1986 to industries and under Section 18(1)(b) of the Water (Prevention and Control of Pollution) Act, 1974.
• Implementation of the National Lake Conservation Plan (NLCP) and National Wetland Conservation Programme (NWCP) for the conservation and management of identified lakes and wetlands in the country which emerged in February 2013 into an integrated scheme of National Plan for Conservation of Aquatic Eco-systems(NPCA) to undertake various conservation activities including interception, diversion and treatment of wastewater, pollution abatement, lake beautification, biodiversity conservation, education and awareness creation, community participation.

 

4. Soil Pollution

• Soil is a thin layer of organic & inorganic materials that covers the Earth’s rocky surface. Soil pollution is defined as the ‘addition of substances to the soil, which adversely affects physical, chemical and biological properties of soil and reduces its productivity.’
• It is a build-up of persistent toxic compounds, chemicals, salts, radioactive materials or disease-causing agents in soil which have adverse effects on plant growth, and human and animal health.
• A soil pollutant is any factor which deteriorates the quality, texture and mineral content of the soil or which disturbs the biological balance of the organisms in the soil.

Causes

• Indiscriminate use of fertilizers, pesticides, insecticides and herbicides.
• Deforestation and soil erosion
• Dumping of large quantities of solid waste
• Pollution due to urbanization

Sources

• Industrial wastes- Industrial waste includes chemicals like mercury, lead, copper, zinc, cadmium, cyanides, thiocyanates, chromates, acids, alkalies, and organic substances.
• Fertilizers & manures- Chemical fertilizers are added to the soil to increase crop yield. Excessive use of chemical fertilizers reduces the population of soil-borne organisms and the crumb structure of the soil, productivity of the soil and increases salt content of the soil.
• Pesticides- Pesticides are chemicals that include insecticides, fungicides, algicides, weedicides, and rodenticides sprayed to improve the productivity of agriculture, forestry and horticulture.
• Discarded materials- These include concrete, asphalt, rungs, leather, cans, plastics, glass, discarded food, paper and carcasses.
• Radioactive wastes- Radioactive elements from mining and nuclear power plants, find their way into water and then into soil.
• Other pollutants- Many air pollutants and water pollutants ultimately become part of the soil and the soil also receives some toxic chemicals during weathering of certain rocks.

Types of soil pollution

• Pollution due to urban activities
• Agricultural soil pollution
• Pollution due to industrial effluents and solid wastes

Effects of Soil Pollution

• Agriculture-
• Reduced nitrogen fixation
• Reduced soil fertility
• Increased erosion
• Reduced crop yield
• Loss of soil & nutrients
• Increased salinity
• Deposition of silt in tanks and reservoirs
• Environment-
• Reduced vegetation
• Ecological imbalance
• Imbalance in soil fauna & flora
• Health-
• Dangerous chemicals entering underground water
• Release of pollutant gases
• Biomagnification
• Release of radioactive rays causing health problems
• Urban areas-
• Waste management problems
• Clogging of drains
• Foul smell and release of gases
• Inundation of areas

Control measures

• Reducing chemical fertilizer and pesticide use
• Organic farming
• Use of bio pesticides, bio fertilizers
• Afforestation and reforestation
• Refuse, reduce, reuse, recycle
• Reduction of waste from construction areas

Four R’

• Refuse- Instead of buying new from the market, use the ones that are in the house. Refuse to buy new items though they are prettier than the ones we already have.
• Reduce- Reduce the generation of unnecessary waste, for example carrying own shopping bag, and refusing a bag from the shop.
• Reuse- Do not throw away the soft drink cans or the bottles; cover them with paper paint them with beautiful colors and use them as pencil stands or small vases.
• Recycle- Use shopping bags made of cloth or jute, which can be used over and over again. Segregating the waste and making them for recycling can reduce pollution.

Facts to know

• The Environmental Performance Index, is conducted and written by environmental research centers at Yale and Columbia universities with assistance from outside scientists.
• Different parts of the tree grow at different times of the year. A typical pattern is for most of the foliage growth to occur in the spring, followed by trunk growth in the summer and root growth in the fall and winter.
• Zoological Survey of India(ZSI) was established on 1^st July 1916 to promote the survey, exploration, research & documentation leading to the advancement in our knowledge on various aspects of animal taxonomy of the Indian subcontinent.
• ZSI is a premier institution on animal taxonomy in India under the Ministry of Environment, Forest and Climate Change. ZSI was declared as the designated repository for the National Zoological Collection as per Section 39 of the National Biodiversity Act, 2002.
• Trees provide wood for building and pulp for making paper. They provide habitats for all sorts of insects, birds and other animals.
• Many types of fruits and nuts come from trees like apples, oranges, walnuts, pears, and peaches.
• The sap of trees is food for insects and is used for making maple syrup.
• Trees also help to keep our air clean and our ecosystem healthy. We breathe in oxygen and breathe out carbon dioxide. Trees breathe in carbon dioxide and breathe out oxygen.
• Amur Falcons, which come to roost every year at Doyang Lake during flight from Mongolia to South Africa.
• Amur Falcons are the longest-travelling raptors in the world.
• The world has recognized Pangti village in Nagaland as the world’s Amur Falcon capital, as more than one million birds can be seen in 30 minutes.
• Naga tribesmen used to hunt thousands of Amur falcons for meat. But last year, after a vigorous campaign by wildlife activists, they pledged to protect the bird and since then, not a single bird has been hunted in this area.
• The Indian Resource Panel shall prepare a strategic roadmap for the utilization of secondary resources for meeting developmental needs. India is the first country to constitute a National Resource Panel.
• The Ministry of Environment, Forest & Climate Change has urged Chief Secretaries of Haryana, Uttar Pradesh & Delhi to take effective steps to enforce the ban on burning of wastes in urban areas.

 

5. Noise Pollution

• Noise pollution is an unpleasant noise created by people or machines that can be annoying, distracting, intrusive and physically painful.
• Noise pollution comes from sources like road traffic, jet planes, garbage trucks, construction equipment, manufacturing processes, leaf blowers and boom boxes.
• Sound is measured in decibels(dB). An increase of about 10dB is approximately double the increase in loudness.
• A person’s hearing can be damaged if exposed to noise levels over 75 dB over a prolonged period. The World Health Organisation recommends that the sound level indoors should be less than 30 dB.

Ambient Noise Level Monitoring

• Noise Pollution (Control & Regulation) Rules, 2000 define ambient noise levels for various areas as follows 

Category of area	Limits in decibels(dB) 6 a.m – 10 p.m	Limits in decibels(dB) 10 p.m. — 6 a.m
Industrial area	75 dB	70dB
Commercial area	65 dB	55dB
Residential area	55dB	45dB
Silence Zone	50dB	40dB

 

• The government of India in March 2011, launched a real-time ambient noise monitoring network. Under this network, in phase I, five remote noise monitoring terminals each have been installed in different noise zones in seven metros- Delhi, Hyderabad, Kolkata, Mumbai, Chennai, Bangalore, and Lucknow.
• In phase II, Another 35 monitoring stations will be installed in the same seven cities. Phase III will cover installing 90 stations in 18 other cities.
• Phase III cities are Kanpur, Pune, Surat, Ahmedabad, Dehradun, Nagpur, Jaipur, Indore, Bhopal, Ludhiana, Guwahati, Trivandrum, Bhubaneswar, Gandhi Nagar, Patna, Ranchi, Amritsar, Raipur.
• Silence zone is an area comprising not less than 100 meters around the hospitals, educational institutions, courts, religious places or any other area declared as such by a competent authority.

 

Impacts of Noise

• It creates annoyance to the receptors due to sound level fluctuations. The a-periodic sound due to its irregular occurrences causes displeasure to hearing and annoys.
• The physiological features like breathing amplitude, blood pressure, heartbeat rate, pulse rate, and blood cholesterol are affected.
• Long exposure to high sound levels causes loss of hearing. This is mostly unnoticed but hurts hearing function.
• The working performance of workers/humans will be affected as it distracts the concentration.
• It causes pain, ringing in the ears, feeling of tiredness, thereby affecting the functioning of the human system.
• Noise pollution affects sleeping, thereby inducing people to become restless and lose concentration and presence of mind during their activities.
• The buildings and materials may get damaged by exposure to infrasonic/ultrasonic waves and even collapse.

Control measures

 The techniques employed for noise control can be broadly classified as

• Control at source-
• Maintenance of automobiles
• Reducing the noise levels from domestic sectors
• Control over vibration
• Selection and maintenance of machinery
• Prohibition on the usage of loudspeakers
• Control in the transmission path
• Design of building
• Installation of barriers
• Greenbelt development( planting of trees)
• Using protective equipment
• Reduced exposure time
• Job rotation
• Hearing protection
• Documentation of noise measurements, continuous monitoring and awareness of the need of the hour.

 

6. Radioactive pollution

• Radioactivity is a property of certain elements like radium, thorium, uranium etc, to spontaneously emit protons (alpha particles), electrons(beta particles) and gamma rays(short-wave electromagnetic waves) by disintegration of their atomic nuclei.
• Radioactivity is a phenomenon of spontaneous emission of protons, electrons and gamma rays due to the disintegration of atomic nuclei of some elements. These cause radioactive pollution.

Types of radiations:

• Non-ionizing radiations affect only those components which absorb them and have low penetrability.
• Ionizing radiations have high penetration power and cause breakage of macromolecules.

Radiation particles:

• Alpha particles, can be blocked by a piece of paper and human skin.
• Beta particles can penetrate through the skin, while can be blocked by some pieces of glass and metal.
• Gamma rays can penetrate easily to human skin and damage cells on their way through, reaching far and can only be blocked by a very thick, strong, massive piece of concrete.

Sources:

Natural source-  Cosmic rays from space and terrestrial radiations from radio-nuclides present in earth’s crust like radium-224, uranium-238, thorium-232, potassium-40, and carbon-14.

Man-made source

• Nuclear power plants
• Nuclear weapon
• Transportation of nuclear material
• Uranium mining
• Disposal of nuclear wastes
• Radiation therapy

Atomic explosion

The nuclear arms use uranium-235 and plutonium-239 for fission and hydrogen or lithium as fusion material. Atomic explosions produce radioactive particles that are thrown up high into the air as huge clouds. These particles are carried to long distances by wind and gradually settle over the earth as fall out or are brought down by rain. The fallout contains radioactive substances like strontium-90, cesium-137, iodine-131 etc,

Period of radioactivity

Each radioactive nuclide has a constant decay rate. Half-life is the time needed for half of its atoms to decay. The half-life of a radionuclide refers to its period of radioactivity. The half-life may vary from a fraction of a second to thousands of years. The radionuclides with long half-time are the chief source of environmental Radioactive pollution.

Effects

The Effects of radioactive pollutants depend on

• Half-life
• Rate of diffusion
• Energy-releasing capacity
• Rate of deposition of the pollutant
• Various environmental factors like wind, temperature, and rainfall also influence their effects.

 Radiations are of two types about the mode of their action on cells-

Non-ionizing radiations

• They include shortwave radiation like ultraviolet rays which form a part of solar radiation.
• They have low penetrating power and affect their cells and molecules which absorb them.
• They injured their cells of skin and blood capillaries producing blisters and reddening called sunburns.
• They damage the eyes which may be caused by reflections from coastal sand, and snow when directly looking towards the sun during an eclipse.

Ionizing radiation

• Ionizing radiations have high penetration power and cause breakage of macromolecules.
• They include X-rays, cosmic rays and atomic radiations.
• The molecular damage may produce short range(immediate) or long range effects(delayed).
• Short-range effects include burns, impaired metabolism, dead tissues and death of the organisms.
• Long range of effects are mutations increased incidence of tumours and cancer, Shortening of lifespan and developmental changes.
• The mutated gene can persist in living organisms and affect their progeny.
• The actively dividing cells like embryos, fetuses, cells of the skin, intestinal lining, bone marrow and gamete-forming cells are more sensitive to radiation.
• Some species of animals and plants preferentially accumulate specific radioactive materials. For example, Oysters deposit 65 Zn, fish accumulate 55 Fe, and marine animals selectively deposit 90 Sr.

Control measures

• All safety measures should be strictly enforced. Leakage of radioactive elements should be checked.
• Safe disposal of radioactive waste
• Regular monitoring through frequent sampling and quantitative analysis
• Safety measures against nuclear accident
• Nuclear explosions and the use of nuclear weapons should be completely banned
• Appropriate steps should be taken to protect from occupational exposure.

 Prevention is the best control measure as there is no cure available for radiation damage.

 

7. Solid waste

Solid waste includes garbage, construction debris, commercial refuse, sludge from water supply or waste treatment plants and other discarded materials.

Solid wastes are the abandoned, discarded waste materials. Solid waste also includes discarded materials including solid, semi-solid, liquid, and compressed gaseous material, resulting from industrial, commercial, mining and agricultural operations and from community activities. However, it doesn’t include solid or dissolved materials in domestic sewage or dissolved materials in irrigation return flows or industrial discharges.

Plastic waste: Plastics are considered to be one of the wonderful inventions of the 20^th century. They are widely used as packing and carry bags because of cost and convenience. But plastics are now considered an environmental hazard due to the ‘ throw away culture’.

Sources of waste pollution

• Health and medicine
• Household
• Air/ rail travel
• Hotel and catering

Effects

• Solid waste leads to an increase in disease-causing organisms like mosquitoes, flies etc., to thrive freely and increase in population.
• Burning of solid waste leads to air pollution.
• Plastic bags contaminate foodstuffs due to the leaching of toxic dyes and the transfer of pathogens.
• The land gets littered by plastic bag garbage and becomes unhygienic.
• Conventional plastics have been associated with reproductive problems in both humans and wildlife.
• Burning of plastics, especially PVC releases this dioxin and also furan into the atmosphere. Thus, conventional plastics, right from their manufacture to their disposal are a major problem to the environment.
• Dioxin (highly carcinogenic, toxic) by-product of the manufacturing process is one of the chemicals believed to be passed on through breast milk to the nursing infant.
• Careless disposal of plastic bags chokes drains, blocks the porosity of the soil and causes problems for groundwater recharge.
• Plastic bags deteriorate soil fertility as they form part of manure and remain in the soil for years.
• Plastic disturbs the soil microbe activity. The terrestrial and aquatic animals misunderstand plastic garbage as foodstuff, swallow them and die.
• These plastic bags find their way into the city drainage system, leading to blockage causing inconvenience, difficulty in maintenance, and creating an unhygienic environment resulting in health hazards and spreading of waterborne diseases.
• Designing eco-friendly, biodegradable plastics is the need of the hour.

Types of solid wastes:

• With rising urbanization and changes in lifestyle, and food habits, the amount of municipal solid waste has been increasing rapidly.
• Municipal solid waste consists of household waste, construction and demolition debris, sanitation residue and waste from streets.
• 70% of the Indian cities lack adequate capacity to transport it and there are no sanitary landfills to dispose of the waste. The existing landfills are neither well equipped and are not lined properly to protect against contamination of soil and groundwater.
• Over the last few years, the consumer market has grown rapidly leading to products being packed in cans, aluminium foils, plastics and other such non-biodegradable items that cause incalculable harm to the environment.
• In 1947, cities and towns in India generated an estimated 6 million tonnes of solid waste, in 1997 it was about 48 million tonnes.
• More than 25% of the municipal solid waste is not collected at all.

• Hospital waste is generated during the diagnosis, treatment or immunization of human beings or animals in research activities or the production, or testing of biologicals.
• Chemicals like formaldehyde and phenols, which are used as disinfectants, and mercury which is used in thermometers or equipment that measures blood pressure are disposed of.
• It may include wastes like soiled waste, disposables, anatomical waste, cultures, discarded medicines, chemical wastes, disposable syringes, swabs, bandages, body fluids, human excreta etc,
• These are highly infectious and can be a serious threat to human health if not managed in a scientific and discriminatory manner.
• Surveys carried out by various agencies show that the healthcare establishments in India are not giving attention to their waste management.
• After the notification of the bio-medical waste rules, in 1998, these establishments are slowly streamlining the process of waste segregation, collection, treatment and disposal.

• Industrial and hospital waste is considered hazardous as it contains toxic substances. Hazardous wastes could be highly toxic to humans, animals and plants and are corrosive highly inflammable or explosive.
• India generates around 7 million tonnes of hazardous wastes every year, most of which are concentrated in the following states- Tamil Nadu, Andhra Pradesh, Bihar, Uttar Pradesh.
• In the industrial sector, the major generators of hazardous waste are the metal, paper, chemical, pesticides, dyes, refining and rubber goods industries.
• Household waste that can be categorized as hazardous waste includes old batteries, shoe polish, paint tins, old medicines and medicine bottles.
• Direct exposure to chemicals in hazardous waste like mercury and cyanide can be fatal.

 

Treatment and disposal of solid waste

Land  Fills

Landfills are generally located in urban areas. It is a pit that is dug in the ground. The garbage is dumped and the pit is covered with soil every day thus preventing the breeding of flies and rats. Thus everyday garbage is dumped and sealed. After the landfill is full, the area is covered with a thick layer of mud and the site can be developed as a park or parking lot.

All types of wastes are dumped in landfills and when water seeps through them it gets contaminated and in turn, pollutes the surrounding area. This contamination of groundwater and soil through landfills is known as leaching.

Open Dumps

Open dumps refer to uncovered areas that are used to dump solid waste of all kinds. The waste is untreated, uncovered and not segregated. The waste is untreated, uncovered and not segregated. It is the breeding ground for flies, rats and other insects that spread disease. The rainwater run-off from these dumps contaminates nearby land and water thereby spreading disease. Treatment by open dumps is to be phased out.

Incineration Plants

The process of burning waste in large furnaces at high temperatures is known as incineration. The recyclable material is segregated and the rest of the material is burnt and ash is formed.

Burning garbage is not a clean process because it produces tonnes of toxic ash and pollutes air and water.

Sanitary Landfills

Sanitary landfill is more hygienic and built methodically to solve the problem of leaching. These landfills are coated or lined with materials that are impermeable like plastics and clay, and built over impermeable soil. Constructing sanitary landfills is very costly.

Composting

• Composting is a biological process in which microorganisms, mainly fungi & bacteria decompose degradable organic waste into humus in the presence of oxygen.
• This finished product, which looks like soil is high in carbon and nitrogen, and is an excellent medium for growing plants.
• Composting increases the water-holding capacity of soil and makes it easier to cultivate. It helps the soil retain more plant nutrients.
• It recycles the nutrients and returns them to the soil as nutrients.
• Apart from being clean, cheap and safe, composting can significantly reduce the amount of disposable garbage.

Pyrolysis

Pyrolysis is one of the technologies available to convert biomass to an intermediate liquid product that can be refined to drop-in hydrocarbon biofuels, oxygenated fuel additives and petrochemical replacements. It is the process of heating an organic material in the absence of oxygen.

Pyrolysis of carbonaceous wastes like firewood, coconut, cashew shell, palm waste, corn combs, rice husk, paddy straw and saw dust yields charcoal along with products like tar, methyl alcohol, acetic acid, acetone and fuel gas.

Vermiculture

VERMICULTURE means artificial rearing or cultivation of worms especially earthworms and the technology is the scientific process of using them for the betterment of human beings. The earthworms break the waste and the added excreta of the worms makes the compost very rich in nutrients. Vermicompost is the excreta of the earthworm, which is rich in humus.

Minimizing Waste

Waste minimization entails limiting the amount of waste that is generated, helping to eliminate the production of persistent and harmful wastes, and effectively supporting efforts that promote a sustainable society.

Waste Minimizing Circles are those that help small and medium industrial clusters in waste minimization in their industrial plants.

This is assisted by World Bank with the Ministry of Environment and Forests acting as the nodal ministry. The project is implemented with the assistance of the National Productivity Council(NPC), Delhi.

 

8. E-WASTE

• E-waste is a popular, informal name for electronic products nearing the end of their useful life.
• Computers, televisions, VCRs, stereos, copiers and fax machines are common electronic products. Many of these products can be reused, refurbished, or recycled.
• E-waste is not hazardous if it is stocked in safe storage recycled by scientific methods or transported from one place to the other in parts or totality in the formal sector. The e-waste can be considered hazardous if recycled by primitive methods.

Sources of E-waste

 

Pollutant	Source	Health effects
Cadmium	Occurs in SMD chip resistors, infrared detectors, and semiconductor chips. Old cathode ray tubes containing cadmium.	Toxic cadmium compounds accumulate in the human body, especially in the kidneys.
Mercury	22% of yearly consumption is used in electrical equipment. Mercury is used in thermostats, sensors, relays, switches, medical equipment, lamps, mobile phones, batteries, and flat panel displays.	Mercury can cause damage to the brain, kidneys, and fetus. A developing fetus is highly vulnerable to mercury exposure. When inorganic mercury spreads out in the water, it is transformed into methylated mercury which bio-accumulates in living organisms and concentrates through the food chain (fish).
Lead	Used in glass panels and gaskets in computer monitors, solder in printed circuit boards and other components.	It causes damage to central and peripheral nervous system, blood systems, kidneys and reproductive system in humans. It affects the endocrine system and impedes brain development in children.
Hexavalent Chromium	Chromium VI is used as a corrosion protector of untreated, galvanized steel plates, and decorative /hardener PVC. Dioxin is released when PVC is burnt.	Chromium VI can cause DNA damage and is extremely toxic in the environment.
Barium	Barium is a soft silvery-white metal that is used in computers in the front panel of a CRT, to protect users from radiation.	Studies have shown that short-term exposure to barium causes brain swelling, muscle weakness, and damage to the heart, liver, and spleen.
Toners	Found in the plastic printer cartridge containing black & colour toners.	Inhalation is the primary exposure pathway, acute exposure may lead to respiratory tract irritation. Carbon black was classified as a class 2B carcinogen. Colour toners may contain heavy metals.
Beryllium	Beryllium is commonly found on motherboards and  finger clips. It is used as a copper-beryllium alloy to strengthen connectors, and tiny plugs while maintaining electrical conductivity.	Exposure to beryllium causes lung cancer, a skin disease that is characterized by poor wound healing & wart-like bumps. People can develop beryllium disease many years following the last exposure.
Phosphor- additives	Phosphor is an inorganic chemical compound that is applied as a coat on the interior of the CRT faceplate.	Phosphor coating on cathode ray tubes contains heavy metals like cadmium & rare earth metals like zinc, and vanadium as very toxic additives. This is a serious hazard posed by those who dismantle CRTs by hand.

 

E-Waste in India:

• According to “The Global E-Waste Monitor 2014”, 17 lakh tonnes of E-waste generation was reported in the country in 2014. No comprehensive State-wise incentivization of e-waste generation in the country is done.
• In India, among all the cities, Mumbai ranks first in generating e-waste followed by Delhi, Bangalore, Chennai, Kolkata, Ahmedabad, Hyderabad, Pune, Surat and Nagpur.
• The 65 cities generate more than 60% of the total generated e-waste, whereas, 10 states generate 70% of the total e-waste.
• The recycling process, if not carried properly, can cause damage to human beings through inhalation of gases during recycling, contact of the skin with hazardous substances and contact during acid treatment used in the recovery process.
• Most of the e-waste recycled in India in unorganized units, which engage a significant number of manpower. Recovery of metals by primitive means is a hazardous act.
• A holistic approach is needed to address the challenges faced by India in e-waste management. A suitable mechanism needs to be evolved to include small units in the unorganized sector and large units in the organized sector into a single value chain.
• Proper education, awareness and most importantly alternative cost-effective technology need to be provided so that better means can be provided to those who earn their livelihood from this.

 

9. Thermal Pollution

• Thermal pollution sometimes called ‘thermal enrichment’ is the degradation of water quality by any process that changes ambient water temperature.
• Thermal pollution is the rise or fall in the temperature of a natural body of water caused by human influence.
• Thermal pollution, unlike chemical pollution, results in a change in the physical properties of water.
• A common cause of thermal pollution is the use of water as a coolant by power plants and industrial manufacturers.
• Urban runoff -stormwater discharged from rooftops, roads and parking lots, reservoirs can also be a source of thermal pollution.

Major sources

• Soil erosion
• Water as a cooling agent in industrial facilities
• Power plants creating electricity from fossil fuel
• Deforestation  of the shoreline

Ecological effects

The change in temperature impacts organisms by

• Decreasing oxygen supply-
• Warm water contains less oxygen.
• Elevated temperature typically decreases the level of dissolved oxygen(DO) in water. So there is a decrease in the rate of decomposition of organic matter.
• Green algae are replaced by less desirable blue-green algae. Many animals fail to multiply.
• It also increases the metabolic rate of aquatic animals resulting in the consumption of more food in a shorter time than if their environment were not changed.
• An increased metabolic rate may result in food source shortages, causing a sharp decrease in population.
• Changes in the environment may result in a migration of organisms to another, environment and to immigration of fishes that normally live in warm water.
• The problem of compromising food chains of the old & new environment causes a loss in biodiversity.
• Very minute temperature variations can cause significant changes in organism metabolism and other cellular biology effects. These changes may include rendering cell walls less permeable to necessary osmosis, coagulation of cell proteins, and alteration of enzyme metabolism.
• Affecting ecosystem composition-
• Primary producers are affected by warm water because higher water temperature increases plant growth rates, resulting in a shorter life span and species overpopulation.
• This causes algal bloom which reduces the oxygen levels in the water.
• The higher plant density results in reduced light intensity, decreases photosynthesis and leads to an increased plant respiration rate which is termed eutrophication.
• A large increase in temerity leads to the denaturing of life-supporting enzymes by breaking down hydrogen and disulfide bonds within the quaternary structure of the enzymes.
• Decreased enzyme activity in aquatic organisms can cause problems like the inability to break down lipids, which leads to malnutrition.

Ecological Effects

Thermal pollution is also caused by the release of cold water from the base of reservoirs into warmer rivers. This affects fish eggs and larvae, macro-invertebrates and river productivity.

Control measures

• Instead of discharging hot water into lakes and streams, power plants and factories can pass the hot water through cooling towers or cooling ponds, where evaporation cools the water before it is discharged.
• Alternatively power plants can be designed or refitted to be more efficient and to produce less waste heat in the first place.
• Cogeneration- it is the process through which, the excess heat energy from generating electricity can be used in another manufacturing process that needs such energy.
• To prevent thermal pollution due to revegetation, the prescription is simple- revegetation, leaf strips of trees and vegetation along streams and shorelines should be avoided.
• All efforts to control erosion also play an effective role in keeping water clearer and thus cooler.

 

10. Plastic pollution

Plastic pollution is the accumulation of plastic objects and particles like plastic bottles, and micro-beads in the earth’s environment that adversely affects humans, wildlife and their habitat.

The marine resource covering 70% of the earth’s surface is a key asset in the biosphere.

The health of the marine food web and the fisheries resources invariably depend upon the long-term viability of the autotrophic algae and the zooplankton in the marine food web.

Plastics represent the latest contamination in the marine environment, increased use of plastics has led to negative environmental impacts.

Marine Environment vs Plastics

There are differences between the fate of plastics debris in the ocean environment as opposed to the land environment.

• The rate of Ultraviolet radiation-induced photo-oxidative degradation of plastics floating or submerged at sea is very much slower than that exposed to the same solar radiation on land.
• Unlike on land there is no easy means of retrieval, sorting and recycling of plastic waste that enters into the ocean.
• These two factors generally result in extended lifetimes for plastics at sea.
• The plastic waste that has been introduced into the world’s oceans must accumulate for the most part intact and unmineralized in the marine environment.

Microplastics

Microplastics are fragments of any type of plastic less than 5mm in length. They cause pollution by entering natural ecosystems from a variety of sources, including cosmetics, clothing, food packaging and industrial processes.

Sources

The existence of microplastics in the environment is often established through aquatic studies. Microplastics contribute up to 30%  of the world’s oceanic pollution and in many countries are a bigger source of marine plastic pollution than the visible larger pieces of marine litter, according to a 2017 IUCN report.

The main sources of microplastics include

• Wearing and tearing of vehicle tires
• Textile fibers
• Cosmetic industry
• Fishing industry
• Manufacturers of plastic goods
• Packaging and shipping industries
• Sewage treatment plants

Effects 

• Marine organisms face many problems by taking microplastics. They are entangled, ingested, suffocated and debilitation often leading to death.
• Large amounts of plastics currently in the environment, exposed to degradation, but that has many years to decay.
• Some corals like Pocillopora verrucosa, are ingested microplastics.
• It is unknown to what degree microplastics accumulate in humans. The presence of polymers in human blood in 17- 22 healthy individuals is reported.
• Microplastics might affect human physiology, forming complexes with heavy metals or other chemical compounds and acting as vectors for bringing them into the body.

Plastic in the Land Environment

• Causing illness and possible death of animals that may feed on plastics from garbage bins.
• Choking of drains by plastic carry bags which may lead to an unhygienic environment and waterborne diseases.
• Non-biodegradable and impervious nature of plastics disposed on soil which may arrest recharge of groundwater aquifers.
• Presence of additives and plasticizers, fillers, flame retardants, and pigments used in plastic products which have the potential to cause adverse health impacts and groundwater pollution.

 

11. 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. This process is used to clean up oil spills or contaminated groundwater.

• For organic pollutants, which are generally more susceptible to biodegradation than heavy metals, bioremediation usually involves oxidations.
• Using bioremediation techniques, TERI(The Energy & Research Institute) developed a mixture of bacteria called ‘oil zapper’ which degrades the pollutants of oil-contaminated sites, leaving no harmful residues. This technique is not only environmentally friendly but also budget-friendly.
• Bioremediation techniques can be classified as in situ techniques and ex-situ techniques.
• In both techniques, additional nutrients, vitamins, minerals and pH buffers are added to enhance the growth and metabolism of the microorganisms.

In situ techniques

It involves the treatment of the contaminated material at the site.

• Biostimulation – The population of the helpful bacteria can be increased by adding nutrients. Specific to marine oil spills, nitrogen and phosphorus were key nutrients in biodegradation.
• Bioventing- It is a process that increases the oxygen or airflow into the unsaturated zone of the soil, this in turn increases the rate of natural in situ degradation of the targeted hydrocarbon contaminant.
• Bioattenuation- During bioattenuation, biodegradation occurs naturally with the addition of nutrients or bacteria. The microbes present will determine the metabolic activity and act as natural attenuation.
• Biosparging- It is the process of groundwater remediation as oxygen and possible nutrients are injected. When oxygen is injected, indigenous bacteria are stimulated to increase the rate of degradation.

Ex situ techniques

It involves the removal of contaminated material to be treated elsewhere.

• Bioreactors- It involves the processing of contaminated solid materials or water through an engineered containment.
• Land farming- The contaminated soil is excavated and spread over a prepared bed and periodically tilled until pollutants are degraded. The goal is to stimulate indigenous biodegradative micro-organisms and facilitate aerobic degradation of contaminants.
• Biopiles- It is a hybrid form of land forming and composting. Essentially, engineered cells are constructed as aerated composted piles. Typically used for the treatment of surface contamination with petroleum hydrocarbons.

Genetic Engineering Approaches

• Phytoremediation- It is the use of plants to remove contaminants from water and soil.
• Phytostabilization- It is a technique in which plants reduce the mobility and migration of contaminated soil. Leachable constituents are adsorbed and bound into the plant structure so that they form an unstable mass of plant from which the contaminants will not re-enter the environment.
• Phytoextraction- It is the process by which plants accumulate contaminants in the roots and above-ground shoots or leaves. This process is also known as phytoaccumulation.
• Phytotransformation- It is also known as phytodegradation. It refers to the uptake of organic contaminants from soil, sediments or water and their transformation into more stable, less toxic, and less mobile.
• Rhizofiltration- It is a water remediation technique that involves the uptake of contaminants by plant roots. Rhizofiltration is used to reduce contamination in natural wetlands and estuary areas.
• Phyto / Rhizodegradation- It is the breakdown of contaminants through the activity existing in the rhizosphere. This activity is due to the presence of proteins and enzymes produced by plants or by microorganisms like bacteria, yeast, and fungi.
• Mycofiltration- It is a similar process of using fungal mycelia to filter toxic waste and microorganisms from water in soil.
• Mycoremediation- It is a form of bioremediation in which fungi are used to decontaminate the area.

Advantages of bioremediation

• The destruction of target pollutants is possible.
• Useful for the destruction of a wide variety of contaminants.
• Environment friendly
• Less expensive

Disadvantages

• Biological processes are often highly specific.
• Bioremediation is limited to those compounds that are not susceptible to rapid and complete degradation.
• It is difficult to extrapolate from pilot-scale studies to full-scale field operations.
• Bioremediation often takes longer time than other treatment processes.

 

 

12. Acid Rain

Acid rain acid deposition is a broad term that includes any form of precipitation with acidic components like sulfuric acid or nitric acid that fall to the ground from the atmosphere in wet or dry forms.  Acid rain has a pH level lower than drinking water(6.5-8.5) and ranges from 4-5. Acid rain can have harmful effects on plants, aquatic animals and infrastructure.

 PH scale

• The pH is a measure of how acidic or basic water is.
• The pH denotes the potential of hydrogen or the power of hydrogen in an aqueous solution.
• A pH less than 7 is acidic and a pH greater than 7 is basic.
• It ranges from 0 – 14, where  7 is neutral.
• It was devised in 1909  and is a logarithmic index for the hydrogen ion concentration in an aqueous solution.
• PH value decreases as hydrogen ion levels increase.

 Types

 Dry deposition

• The acid chemicals may become incorporated into dust or smoke and fall to the ground through dry deposition, sticking to the ground, buildings, vegetation etc in areas with dry weather.
• Dry deposited gases and particles can be washed from these surfaces by rainstorms through runoff.
• This runoff water makes the resulting mixture more acidic.
• About half of the acidity in the atmosphere falls back to the earth through dry deposition.

  Wet deposition

• If the acid chemicals in the air are blown into areas where the weather is wet, the acids can fall to the ground in the form of rain, snow, fog, or mist.
• As this acidic water flows over and through the ground, it affects a variety of plants and animals.
• The strength of the effects depends on several factors, including how acidic the water is, the chemistry and buffering capacity of soils involved, and the types of trace fish and other living things that rely on water.
• Precipitation removes gases and particles from the atmosphere by the incorporation of particles into cloud drops, which fall to the ground and washout which occurs when materials below the cloud are swept down by rain or snowfall.

  Sources

Sulphur

• Man-made sources-
• Burning of coal(60% of SO₂)
• Burning of petroleum products(30% of SO₂)
• Smelting of metal sulfide ores to obtain the pure metals
• Industrial pollution of sulphuric acid in metallurgical, chemical and fertilizer industries.
• Natural sources-
• Oceans and seas
• Volcanic eruptions
• Biological processes in the soil like decomposition of organic matter.

 Nitrogen

• Anthropogenic sources-
• Combustion of oil, coal and gas
• Forest fires
• Natural sources-
• Volcanic eruption
• Lightning
• Biological activity

 Formic acid

• Biomass burning due to forest fires causes the emission of formic acid(HCOOH) and formaldehyde(HCHO).
• A large fraction of formaldehyde gets photooxidation and forms formic acid in the atmosphere.

 Other acids include hydrochloric acid(smoke stacks), Phosphoric acid, Chlorine, carbon monoxide and carbon dioxide(automobiles) which becomes carbonic acid.

 Characteristics of acid rain

 Areas which are prone to acid rain attacks have some common characteristics as follows-

• These areas are concentrated in the industrialized belt of the northern hemisphere.
• SOX & NOX that create acid rain are often transported to a distance far away from their points of origin by the wind so that the adverse effects of pollution are also experienced at places remote from the place of genesis.
• The problem is further compounded as the environmental damage caused by acid rain is not uniform but is area-specific.
• These areas are often upland or mountain areas which are well watered by rain and snow.
• Due to the abundance of water, they possess numerous lakes and streams and also have more land covered with vegetation.

In India

In India, the first report of acid rain came from Mumbai in 1974. Instances of acid rain are being reported in metropolitan cities. In India, the annual SO2 emission has almost doubled in the last decade due to increased fossil fuel consumption. Lowering of soil pH is reported from northeast India, coastal Karnataka and Kerala, parts of Orissa, West Bengal and Bihar.

Indicators of acid rain

 Lichens(symbiotic association of algae & fungi) serve as good bio-indicators for air pollution. In the variety of pH around 6.0, several animals that include food items for fish decline. These include freshwater shrimp, crayfish, snails and some mussels.

 Chemistry of acid rain

• The atmosphere receives oxides of sulfur and nitrogen from natural and man-made sources.
• Some of these oxides fall back directly to the ground as dry deposition, either close to the place of origin or some distance away.
• Sunlight stimulates the formation of photo oxidants in the atmosphere.
• These photo-oxidants interact with oxides of sulfur and nitrogen to produce sulfuric acid and nitric oxide by oxidation.
• The oxides are of sulfur and nitrogen, Photo-oxidants and other gases.
• Acid rain containing ions of sulphate, nitrate, ammonium and hydrogen falls as wet to deposition.

 Impact of acid rain

Soil

• The exchange of hydrogen ions and nutrient cations like potassium and magnesium in the soil causes leaching of the nutrients, making the soil infertile.
• This is accompanied by a decrease in the respiration of soil organisms.
• The nitrate level of the soil is also found to be decreased. An increase in ammonia in the soil due to a decrease in other nutrients decreases the rate of decomposition.
• The impact of acid rain on soil is less in India because Indian soils are mostly alkaline with good buffering ability.

Vegetation

• Acid aims affect trees and undergrowth in forests in several ways, causing reduced or abnormal growth.
• Discoloration and loss of foliar biomass.
• Loss of feeder-root biomass, especially in conifers.
• Increase in susceptibility of damage to secondary root and foliar pathogens.
• Death of herbaceous vegetation beneath affected trees.
• Premature senescence of older needles in conifers.
• Prodigious production of lichens on affected trees.
• Death of affected trees.

Micro-organisms

• PH determines the proliferation of any microbial species in a particular environment and the rate at which it can be produced.
• The optimum pH of most bacteria and Protozoa is near neutrality, most fungi prefer an acidic environment, and most blue-green bacteria prefer an alkaline environment.
• So after a long run of acid rain, microbial species in the soil and water shift from bacteria-bound to fungi-bound and cause an imbalance in the microflora.
• This causes a delay in the decomposition of soil organic material and an increase in fungal disease in aquatic life and forest.

Wildlife

• The effects of acid rain on wildlife are not very obvious and difficult to document.
• Several direct and indirect effects of acid rain are reported like productivity, and survival of wildlife populations.
• Acid rain can directly affect the eggs, and tadpoles of frogs and salamanders that breed in small forest ponds.
• It has been postulated that acid rain can indirectly affect wildlife by allowing metals bound on soils and sediments to be released into the aquatic environment, where toxic substances may be ingested by animals, like birds, that feed in such an environment.

Humans

• Acid rains affect human health in several ways.
• Some direct effects include chronic bronchitis, pulmonary emphysema, and cancer.
• Reduced visibility, and irritation of the skin, eyes, and respiratory tract are some more effects.
• Some indirect effects include food poisoning, drinking water pollution etc.
• An increase in the levels of toxic heavy metals like manganese, copper, cadmium and aluminium also contribute to the detrimental effects on human health.

Damage on materials

 

Material	Type of impact	Principal pollutants
Building stone	Surface erosion soiling, black crust formation.	Sulphur oxides and other acid gases.
Metals	Corrosion, tarnishing	Sulphur oxides, other acid gases
Paints, organic coatings	Surface erosion, discolouration, soiling	Sulphur dioxides, hydrogen sulphide
Ceramics, glass	Surface erosion, surface crust formation	Acid gases, especially fluoride containing
Paper	Discoloration, embrittlement	Sulphur oxides
Textiles	Fading, colour change	Nitrogen oxides, ozone
Photographic materials	Micro-blemishes	Sulphur oxides
Leather	Weakening, powdered surface	Sulphur oxides
Rubber	Cracking	Ozone

 

Socio-economic impacts of acid rain: The adverse impact of acid rain on farming, and fishing leads to the deterioration of life quality indices like GNP & per capita income, especially in the predominantly agricultural and developing countries like India.

Trigger effect of acid rain: A low pH of the rainwater and subsequent increased acidity in the environment can trigger or aggravate the effects of certain harmful pollutants.

Mercury

• Methyl mercury and related short-chain alkyl mercurial compounds are most dangerous to humans, as they accumulate in edible fish tissue.
• The use of lime has helped in reducing the mercury levels in fish.
• Although acid deposition may not increase the production of methyl mercury, it may increase the partitioning of methyl mercury into the water column.

Cadmium

• A decrease in water pH from 6.5 to 4.5 can result in a fivefold increase in cadmium & could cause renal tubular damage.
• Cadmium can enter the drinking water supply through corrosion of galvanized pipe or from the copper-zinc galvanized pipes or Cu-Zn solder used in the distribution systems.

Aluminium

• Acidified waters are known to leach substantial amounts of aluminium from watersheds.
• Even at relatively low levels, aluminium is implicated in dialysis dementia, a disorder of the central nervous system, which may be toxic to individuals with impaired kidney function.

Lead

• High blood lead levels in children (>30mg/ml) are believed to induce biochemical & neurophysiological dysfunction.
• Fetuses and infants are highly susceptible to drinking water lead contamination.
• Low lead levels in the blood cause mental deficiencies and behavioral problems.

Asbestos

Asbestos in natural rock can be released by acidic waters.

Control measures

• Reducing the emissions of SO2 from power stations by burning less fossil fuel, and using alternate energy sources like tidal, wind, hydropower etc.
• Buffering the practice of adding a neutralizing agent to the acidified water to increase the pH is one of the important control measures. Usually, lime in the form of calcium oxide and calcium carbonate is used.
• Using low sulphur fuel
• Desulphurization
• Modification of engines
• Decreasing emission of NOX from power stations
• Emissions of SOx can be controlled by converting to sulphuric acid, elemental sulphur and neutralizing it & using it in the manufacture of other products.

Environment pollution-Human Health:

• Pollution inventory, and apportionment studies that assess the relative contribution of different sources are looked at in insolation and not within a coherent framework of health protection.
• Globally, studies show that vehicles contribute from a quarter to close to half of the particulates in cities.
• It is not expressed that people are exposed to higher health-damaging pollutants than that occurs in ambient conditions.
• Exposure to vehicular fumes is highest on the road and up to 500 meters from the point. The majority of the population lives in this zone.
• With each breath we inhale 3-4 times more pollutants than the ambient air concentration.
• People are exposed to a mixture of pollutants whose combined effect has a serious health impact. The benefits are greater when pollution sources are regulated for multi-pollutants.
• Delhi’s air is thick with particulate matter, nitrogen oxides, ozone and air toxins.
• There is merit in NGT’s focus on diesel emissions which is a multi-pollutant mixture classified as a class one carcinogen for its strong link with lung cancer. Exposure to toxins should be eliminated.
• India is experiencing a rapid health transition, with a large and rising burden of chronic diseases, estimated to be more than half of all deaths and years lost to illness.
• Cancer, heart stroke and chronic lung diseases are now major public health problems that are strongly influenced by air pollution.

Industrial sectors- Categories

• The Ministry of Environment, Forest and Climate Change (MoEFCC) developed the criteria for categorization of the industrial sector into Red, Orange, Green and white categories based on the Pollution index which is a function of the emissions (air pollutants), effluents(water pollutants), hazardous wastes generated and consumption of resources.
• The Pollution Index (PI) of any industrial sector is a number from 0 to 100 and the increasing value of PI denotes the increasing degree of pollution load from the industrial sector.
• Re-categorization of industries based on their pollution load is a scientific exercise.
• The old system of categorization was creating problems for many industries and was not reflecting the pollution of the industries.
• The new categories will remove this lacuna and will give a clear picture. The new category of white industries which is practically non-polluting will not require Environment Clearance (EC) and Consent, which will help in getting finance from lending institutions.
• No Red category of industries shall normally be permitted in the ecologically fragile area.