Pollution is a negative change in air, water and soil. The change is closely associated with both chemical and biological properties of air, water and soil. It is significantly necessary to take precautionary measures to protect and hence improve the quality of the environment. This article aims to discuss different environmental issues and will highlight the factors that need to be taken care of to deal with these issues efficiently.

What is Environmental Pollution?

Pollution refers to undesirable changes in the physical, chemical, or biological aspects of the environment, which makes it hazardous for humans and other living organisms and deteriorates our natural resources.

Classification of Pollutants

Definition: According to the Environment Protection Act, 1986, a pollutant is any solid, liquid, or gaseous substance present in a concentration that may be injurious to the environment.

Types of Pollution

Pollution is mainly classified into five types:

• Air Pollution
• Water Pollution
• Land Pollution
• Radioactive Pollution
• Noise Pollution

Fig: Types of Pollution

Air Pollution

Definition: Air pollution is described as an imbalance in the quality of air by the addition of undesirable and harmful pollutants into the atmosphere.

Sources of Air Pollution

Air pollutants can be conveniently classified into the following three main groups:

Oxides of carbon, sulphur, nitrogen, and hydrocarbon are the main gaseous primary air pollutants.

Photochemical Smog: It occurs in urban areas. It is a secondary gaseous air pollutant that is produced by photochemical reactions. Automobile exhaust contains hydrocarbons and nitrogen oxides that synthesise ozone and PAN (Peroxyacetyl Nitrate). Further, peroxyacetyl Nitrate reacts with nitrogen oxides and forms photochemical smog.

Effects of Air Pollution

Air pollution has a profound influence on biological systems and the environment. Some major effects of air pollution are as follows:

1. Effect on human health: The effect of gaseous pollutants upon their solubility in water which allows their diffusion into the tissues. The effect of particulate matter depends upon the size of particulate matter. Particles larger than 2 microns can be trapped in nasal hairs and the minute particles enter the air tube. The main effects of air pollution on human health can be summarised as follows:

Pollutants	Effects
Carbon monoxide	It combines with haemoglobin and reduces the oxygen-carrying capacity. This leads to exhaustion, reduced vision.
Carbon dioxide	Nausea, headache
Nitrogen oxides	Irritation of eyes, nose, respiratory epithelium in humans reduces the oxygen-carrying capacity of the blood, diminishes pulmonary function. These may be carcinogenic.
Oxides of sulphur	Irritation of mucus lining of lungs, shortness of breath, chronic bronchitis, chronic asthma, emphysema.
Particulate matter	It causes irritation, alter immune defence, decrease pulmonary action, stress the heart and affects the lungs.
Pollen, spores, cysts, bacteria	Allergies of skin and respiratory tract.
Radioactive pollutants	Death of living tissues.

2. Effects on Plants: The response of plants to air pollutants is variable and depends on individual genotype, age, growth, concentration and duration of pollutants.

• (i) Sulphur dioxide interferes with respiration, photosynthesis. It causes chlorosis, plasmolysis, membrane damage, metabolic inhibition.
• (ii) Fluorides and PAN damage leafy vegetables.
• (iii) Ozone and hydrocarbons cause yellowing of leaves, falling of immature fruits and flowers.
• (iv) Nitrogen oxides decrease the yield of crops.

3. Effect on Buildings and climate (Acid rain): It refers to the various ways in which the acids from the atmosphere are deposited on the earth. The oxides of nitrogen and sulphur accumulate in the atmosphere and combine with the water vapour present in the air. The water and oxides of nitrogen and sulphur fall on the building in the form of acid rain (sulphuric acid and nitric acid) after condensation. Our heritage monuments (such as the Taj Mahal) are threatened by the corrosive action of acid deposition.

Fig: Acid Rain

4. Effect on Climate: The greenhouse effect is the progressive and gradual warming of the earth’s temperature. It is caused by the insulating effect of carbon dioxide and other greenhouse gases (methane, chlorofluorocarbons) that have proportionally increased in the atmosphere and causes global warming.

Fig: Greenhouse effect

Control of Air Pollution

Important preventive strategies to control air pollution are as follows:

• (i) Appropriate fuel selection (for example, fuel with low sulphur content) and its efficient utilisation to reduce pollutant level in emission.
• (ii) Modification in industrial processes and equipment to reduce emission.
• (iii) Planting trees reduces the carbon dioxide content in the atmosphere and prevents global warming.
• (iv) Particulate matters from the air can be removed by using arresters, scrubbers, and catalytic converters. Cyclonic separators, filters, and electrostatic precipitators are three types of arresters. The cyclonic separator is used to separate out particulate matter from the industrial effluents. Electrostatic precipitator works on the principle of electric charging of dust particles and collecting them on a differentially charged platform.
• Scrubbers are also used to clean air for both dust and gases by passing it through a dry or wet packing material.

Water Pollution

Definition: The presence of foreign organic, biological, radiological or physical substances in water that tends to lower its quality and constitutes a health hazard is called water pollution. The various categories of water pollutants are as follows:

Physical pollutants increase the temperature of water bodies. It is called an alternative form of water pollution called thermal pollution.

Sources of Water Pollution

Sources of water pollution can be mainly classified into the following two categories:

Power plants and nuclear power stations are the main sources of the thermal pollution of water. The hot wastewater released into the water bodies increases the temperature by about 8-10 degrees Celsius and causes thermal pollution.

Agrochemicals: These are the chemical products used in agriculture to increase the yield of crops. These include pesticides, residues of inorganic fertilisers, plant growth regulators, soil conditioners, etc.  

Surface runoff: The runoff from urban areas mainly contains biodegradable organic pollutants. Industrial sites may contribute to various types of pollutants, like heavy metals, acids, and various inorganic compounds in the water bodies. All these pollutants greatly contaminate our surface water and groundwater resources.

Oil spills: It is the accidental discharge of petroleum in oceans and estuaries. It forms a thick layer called slick, which floats on the surface of the sea and affects the oceanic ecosystem.

Effects of Water Pollution

Water pollution disturbs the aquatic and terrestrial ecosystems. A few adverse effects of water pollution can be described as follows:

1. Biological magnification: An increase in the concentration of toxic substances and pesticides at each trophic level in a food chain is called biological magnification. The concentration of toxic pollutants increases with an increase in the trophic level.

An example of biomagnification is that of DDT, an insecticide that is sprayed on the water bodies to prevent the growth of mosquitoes. There is a progressive increase in the concentration of DDT while passing from plants to birds in the aquatic food chain. This can be summed up as follows:

Fig: Biomagnification of DDT in an Aquatic Food Chain

2. Eutrophication: The process of nutrient enrichment in the water bodies that supports the algal bloom and consequently causes the loss of species diversity in an aquatic ecosystem is called eutrophication. The rapid growth of algae (especially blue-green algae) forms a green cover over the surface water. They consume the dissolved oxygen and often release toxins in the water. Lower the dissolved oxygen, higher the Biological Oxygen Demand (a measurement of oxygen required by aerobic decomposers). The bloom infested-water is a threat to aquatic life.

3. Effects of water pollution on human health: An overview of the effects of water pollution on human health can be discussed as follows:

Sources of water pollution	Health effect
1. Domestic sewage (containing pathogens)	Water-borne diseases (cholera, dysentery, jaundice, etc.)
2. Hg consumption	Minamata disease (observed in Japan).
3. Cadmium consumption	Itai-Itai disease (a painful disease of joints)
4. Excess nitrates	Methemoglobinemia (impairs oxygen transport), called a blue-baby syndrome.
5. Excess fluorides	Skeletal fluorosis (teeth deformity, hardened bones, painful joints)
6. Excess arsenic	black foot disease (diarrhoea, peripheral neuritis)

Control of Water Pollution

The following preventive measures need to be in practice to control water pollution:

• 1. Avoid discharge of sewage and industrial effluents in the water bodies.
• 2. The industrial and municipal wastes are treated in Effluent Treatment Plant (ETP) prior to disposal in water bodies.
• 3. Water Hyacinth can absorb cadmium and other toxic chemicals; hence should be planted in water bodies prone to pollution.
• 4. Reduce, reuse, and recycle are the methods that serve as universal approaches to prohibit all types of pollution.
• 5. Hot water should be cooled before release into the water bodies.
• 6. Wastewater management and solid waste management are the keys to check water pollution.

Soil Pollution

Definition: Any unfavourable alteration in soil by the addition or removal of substances that decrease soil fertility is called soil pollution.

Causes of Soil Pollution

Soil pollution generally results from different human activities. Following are the causes of soil pollution:

• 1. Industrial solid wastes and sludge
• 2. Radioactive wastes
• 3. Municipal wastes, domestic wastes, poultry wastes, livestock.
• 4. Non-biodegradable wastes (plastics, ceramics).
• 5. Pesticides and weedicides
• 6. Opencast mining (a process where the earth’s surface is dug to bring out the underground mineral deposits).

Effects of Soil Pollution

1. Excess use of fertilisers and pesticides reduces the fertility of the soil. At extremity, the soil becomes infertile.
2. Hospital wastes contain organic materials, needles, plastic, glass, etc. Dumping domestic and hospital wastes contaminates the soil with a variety of pathogens that can dangerously affect human health.
3. The surface runoff of pesticides and weedicides in the water bodies facilitate eutrophication in the water bodies.
4. Inorganic fertilisers and pesticides change the chemical properties of soil and can negatively affect soil organisms.

Control of Soil Pollution

1. Planned urbanisation and controlled developmental activities.
2. Safe disposal and management of solid and non-biodegradable wastes.
3. Sewage sludge and industrial solid wastes are used as landfills.
4. Toxic chemicals and hazardous metal-containing material are used as bedding materials for road construction.
5. Biodegradable organic wastes can be transformed into organic manure for agriculture.
6. Other methods to get rid of the soil wastes are incineration (burning in the presence of oxygen) and pyrolysis ( combustion in the absence of oxygen).

Noise or Sound Pollution

Definition: Noise is the form of sound energy that is not appreciated by human ears. Many authorities now consider noise as a pollutant. Noise pollution can be defined as the loud, disturbing sound dumped into the ambient atmosphere without regard to the adverse effects. The sound that ranges from 85 to 120 decibels is harmful and leads to physical discomfort.

Sources of Noise Pollution

The main contributor to soil pollution is from industries, machines, transport vehicles, sound amplifiers, cracker blasting, etc. Jet aircraft landing and take-off create a lot of noise pollution to the inhabitants near the airports.

Effects of Noise Pollution

1. Hearing impairment.
2. Noise negatively affects the heartbeat, peripheral circulation, and breathing patterns.
3. Persistent noise can cause annoyance, irritability, headache and affect the productive performance of humans.
4. Noise also reduces depth and quality of sleep, therefore, affecting overall mental and physical health.

Control of Noise Pollution

1. Soundproof jackets or filters should be used in industries.
2. The plantation of trees also reduces noise pollution.
3. Earmuffs should be used to avoid harm from the noise.
4. Efforts must be made to increase awareness among people about the perils of noise in our surroundings.
5. Noise-zones should be marked near temples, hospitals, and educational institutes.
6. A uniform law should be introduced for controlling and abatement of noise.

Radioactive Pollution

Definition: The physical pollution of natural resources with radioactive materials is called radioactive pollution.

Sources of Radioactive Pollution

The radioactive substances that continuously emit harmful radiation are the sources of radioactive pollution. These radiations can be summarised as follows:

Effects of Radioactive Pollution

1. Non-ionising radiations such as ultraviolet rays produce toxic photoproducts in the cells. It causes snow blindness, inactivation of biochemicals, including DNA and RNA.
2. Ionising radiations such as X-rays, cosmic rays, and atomic rays damage the cells by breaking the macromolecules.
3. Short-range effects of radiation include burns, loss of hairs, subcutaneous bleeding, change in number and proportion of blood corpuscles types, impaired metabolism.
4. Long-range effects of radiation include mutations, the incidence of the tumour, cancer, shortening of life span, and developmental changes.

Control of Radioactive Pollution

1. The release of radioactive elements from nuclear reactors and industries should be totally checked.
2. Safety measures should be strictly enforced.
3. Shielding during work with radionuclides, radioactive operations should be conducted at a sufficient distance.
4. There is no particular cure for harmful radiations. Therefore the use of radioactive substances should be checked to a certain extent.

Global Environmental Issues

1. Global Warming: A continuous increase in the concentration of greenhouse gases (CO₂, CH₄, Chlorofluorocarbons) enhances the greenhouse effect and causes global warming. Global warming refers to the overall increase in the temperature of the earth.
An overall increase in the temperature adversely affects the weather, rise in sea level, melting of glaciers, affects the species distribution, and large changes in the temperature reduce crop productivity.

2. Ozone layer Depletion: Ozone shield in the stratosphere absorbs the harmful UV radiation. CFCs, CH₄, and N₂O escape into the stratosphere and cause the destruction of the ozone layer. In humans, exposure to UV rays causes eye cataracts, skin cancer and diminishes the functioning of the immune system.

3. Land Degradation (Soil Erosion): The removal of an uppermost fertile layer of earth crust is called soil erosion. Land degradation occurs due to strong winds, heavy rains, improper farming and cultivation, floods, salinisation of soil.

4. Deforestation (Forest Destruction): The removal of forests is called deforestation. Deforestation is a serious threat to our economy, quality of life, and environment. Deforestation has intensified soil erosion, recurrence of floods and droughts and loss of precious wildlife. Hence causes an ecological imbalance.

5. Over-population: An exponential increase in the population directly relates to environmental issues. Overpopulation causes exploitation of natural resources, mismanagement of waste disposal. One of the major aspects of over-population is the urbanisation and modernisation that destruct nature and its resources.

6. Degradation of Natural Resources: Improper utilisation, misuse and wastage of resources results in the degradation of natural resources. A few examples of the degradation of natural resources can be listed as follows:
(i) Soil quality, fertility, and structure can be destroyed by overgrazing, mismanaged cropping patterns, excessive use of pesticides and chemicals, and excessive irrigation. These non-friendly activities may lead to sterile soil, soil salinity, waterlogging, etc.
(ii) A long term abuse of soil may lead to desertification.
(iii) Lack of sewage treatment, solid waste management degrade and deteriorate the water resources, soil, and also hazardous to the health of biota.

Environmental Laws of Controlling Environmental Issues

1. The Insecticide Act, 1968 deals with the regulation of import, transport, distribution, use of insecticides.
2. The Water Prevention and Control of Pollution Act, 1974 This act deals with the preservation of water quality and control of water pollution.
3. Environment Protection Act, 1986 This act noticeably brings the protection of air, water, and soil.
4. The Social Forestry Programme, Agroforestry Programme, The Urban Forestry Programme, and National Forest Policy lead to the conservation of forests.

Summary

Our Environment is enriched with several natural resources. Mismanagement, wastage, and over-exploitation of these resources lead to several environmental issues. These issues mainly include air pollution, water pollution, soil pollution, noise pollution, radioactive pollution, etc. Such environmental issues not only cause ill effects on the health of plants, animals, and humans. Moreover, the discrimination of resources also diminishes the nature that leads to major global environmental issues such as ozone layer depletion, global warming, deforestation, land degradation. This article is a summarised collection of different types of environmental issues.

Frequently Asked Questions on Environmental Issues

Frequently asked questions related to environmental issues is listed as follows:

Q.1. What do you mean by environmental pollution?
Ans: Environmental pollution refers to the contamination of air, water, soil, and discrimination of natural resources that contaminate nature’s treasure.

Q.2. What are environmental issues?
Ans: The environmental issues are global warming, ozone layer depletion, air pollution, water pollution, and soil pollution.

Q.3. How can we reduce environmental issues?
Ans: There are many ways to reduce environmental issues. A few are listed as follows:
1. Appropriate selection of fuels.
2. Sewage management and solid waste treatment.
3. Afforestation
4. Reduce, reuse, and recycle.

Q.4. What are the human activities that destroy the environment?
Ans: Overpopulation, exploitation of natural resources, improper waste disposal, deforestation, etc., are the human activities that destroy the environment.

Q.5. What is the problem with ozone depletion?
Ans: Ozone layer depletion allows the harmful UV radiations to reach the earth’s surface that causes eye cataracts, skin cancer and weakens the immunity of a person.

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