Video Lesson

Competencies

At the end of this lesson , you will be able to

• Explain environmental pollution
• Describe air, water and soil pollution
• Describe pollutants of air, water and land
• Describe the effects of air, water and land pollutants
• Describe some of the main methods used to reduce air pollution
• Discuss the causes of air, water and land pollution
• Explain the effects of air, water and land pollution
• Describe some of the methods used to reduce air, water and land pollution
• Carry out a project on the effects of an industry on environment
• Propose safe method of disposing non-biodegradable wastes and recommend method of preventing pollution caused by over use of fertilizers

Brainstorming Question

• Ethiopia’s 2015 Climate Commitment Sets a High Bar for NationalClimate Action. What was this climate commitment to be taken By Ethiopia?
• The Copenhagen summit was a popular international climate change summit. What was the role played by Ethiopia? What were the major is sues of the summit?
• Mention any activity in your area to bring awareness of air pollution and global warming?
  

Key Terms

7.1. Environmental Pollution

Environmental pollution refers to the introduction of harmful substances or products into the environment, causing adverse effects on ecosystems, human health, and the overall balance of nature. Pollution can affect air, water, and soil, leading to significant environmental and health issues. Types of Environmental Pollution

7.1.1. Air pollution

• Air pollution is caused by the presence of contaminant gaseous substances in the air that affect the lives of plants and animals on earth. Some common air pollutants are

sulphur dioxide, nitrogen oxides, carbon monoxide, ozone, hydrocarbons, particulates, chlorofluorocarbons (CFCs), and lead compounds.

• Sulphur dioxide ( SO₂ ): – This enters the atmospheric air from the combustion of coal and petroleum, and during extraction of metals from their sulphide ores. It causes coughing, chest pains and shortness of breath. It is thought to be a cause for bronchitis and lung diseases. It slowly oxidizes to SO₃ by reacting with the oxygen in the air.

• Oxides of nitrogen: – These can be formed in the atmosphere by natural processes .like thunderstorms. Combustion of fossil fuel containing nitrogen compounds as impurities and exhaust gases from furnaces and engines increase the amount of nitric
• oxide, NO, and nitrogen dioxide, NO₂, in the atmosphere. Nitric oxide, NO, catalyzes the decomposition of ozone in the upper layer of the atmosphere to oxygen, thus decreasing the ozone layer: 2O₃ (g) → 3O₂ (g)
• Nitric oxide is oxidized by oxygen to nitrogen dioxide in the presence of ultraviolet light: 2NO(g) + O₂(g) → 2NO₂ (g)

• SO₂, SO₃ and NO₂ react with rainwater and form sulphurous acid (H₂SO₃), sulphuricacid (H₂SO₄) and nitric acid (HNO₃), respectively and cause acid rain. Acid rain accelerates corrosion and the deterioration of metals, buildings, statues and also cause tree defoliation, release of heavy metal ions from soil into water courses and drop in the pH of water in rivers and lakes.

• Hydrocarbons and ozone are responsible for photochemical smog. It is characterized by a reddish-brown haze containing substances irritating to the eye, nose, and lungs, and causes extensive damage to vegetation. Considerable amounts of hydrocarbons are released into the atmosphere by the evaporation of gasoline as un burnt hydrocarbons in auto exhaust. These substances react with ozone to give compounds that contribute to the oxidizing nature of photochemical smog.

• Carbon monoxide: – Most of the carbon monoxide escapes into the atmosphere due to the incomplete combustion of fuel. Prolonged exposure to carbon monoxide impairs vision, produces headaches, and exerts strain on the heart. It also reduces the oxygen carrying capacity of the blood by reacting with hemoglobin.
• Particulates: – Dust storms, forest fires, volcanic eruptions and human activities such as mining and burning coal and oil increase the amount of solid particles in the air. Industrial areas contain particles of limestone, fertilizers, coal, stones, cement and silica. These particulates irritate the lungs and deleteriously affect breathing.
• Chlorofluorocarbons (CFCs): – Chlorofluorocarbons are used as refrigerants, solvents and plastic foam-blowing agents. When entering the atmosphere, they penetrate into the upper layers and interact with ultraviolet radiation as follows: CF₂ Cl₂ → CF₂Cl^. + Cl^.

The free chlorine, Cl, reacts with ozone to form chlorine monoxide and oxygen: Cl^. + O₃ → ClO + O₂
These reactions result in the conversion of ozone to molecular oxygen and contribute to depletion of the ozone layer. This situation in the upper atmosphere allows dangerous ultraviolet radiation to reach the earth’s surface. This radiation causes skin cancer in human beings.

• Volatile Organic Compounds (VOCs): – These are compounds that can easily become gas or vapor. They are mostly released from the burning of gasoline, wood, natural gas, and coal. Other sources of VOCs include thinners and paints, cigarettes, solvents, wood preservatives, air fresheners, furnishings, copy machines and printers, cleaners, pesticides, and disinfectants.
• PCBs (polychlorinated biphenyls): – These are organic chlorine compounds that were at one point extensively used as coolant fluids and dielectric in electrical gadgets, in heat transfer fluids, and in carbonless copy papers.

Excess carbon dioxide: – The combustion of coal and petroleum to generate electricity, move our vehicles, heat our homes and supply power to our industrial machinery causes a significant increase in the concentration of carbon dioxide in the atmosphere.
Combustion of these fuels releases about 20 billion tones of CO₂ annually.

• The increase in the concentration of CO₂ in the atmosphere has resulted in a rise in the average global temperature, owing to the greenhouse effect. Carbon dioxide and water vapor absorb infrared radiation, re-radiated from the earth, behaving like the glass in a greenhouse. Since CO₂ and water vapor absorb heat, they are called green-house gases. Due to the absorption of heat by the greenhouse gases in the atmosphere, the overall effect is global warming (an increase in the average temperature of our planet).

• This rise in global temperature causes melting of polar ice and thus additional water flowing into the oceans. This situation, in turn, results in the rising of the levels of seas and oceans, flooding of coastlines and lowland areas, which can submerge these areas. Heavy metals: Lead contamination in the atmosphere is a result of vehicle engines that use fuels containing tetraethyl lead which is added to the fuel to reduce engine knocking. The use of lead paints also contributes towards lead contamination. High levels of lead cause damage to the brain, kidneys and liver.

What are the potential air pollutants in and around your home?

Methods of Reducing Air Pollution

• Using public transport
• Turn off the lights when not in us
• Recycle and reuse
• Not to use plastic bags
• Reduction of forest fires and smoking
• Use of fans instead of air conditioner
• Use filters for chimney
• Implement afforestation
• Avoid using of products with chemicals
• Avoid usage of crackers

7.1.2. Water Pollution

• Water pollution is the degradation of the quality of water brought by the discharge of untreated sewage, industrial and agricultural waste, and oil spillage. In general, water is said to be polluted if it contains matter that affects the health of living things or causes damage to property. The major water pollutants are nitrate and phosphate fertilizers washed out of the soil, phosphate detergents, untreated sewage, insecticides and herbicides, and the heavy metal ion, acidic and/or basic residues released by industrial processes.

• Phosphate and nitrate fertilizers washed out of the soil and phosphate detergents from untreated water, enter natural water systems, such as streams, rivers, lakes, and seas. These dissolved minerals are valuable nutrients for plants, and their discharge into the water systems accelerates the growth of surface-water plants, such as algae. As a result, less light reaches the bottom-living plants, which reduces the photosynthesis they need to live, and they die.

• When these aquatic plants die, they rot under the action of bacteria which multiply greatly and consume the oxygen dissolved in the water at a rate faster than natural aeration or photosynthesis can replenish. Thus, the amount of oxygen in the water decreases. This depletion of oxygen kills aquatic animals like fish. This sequence of events is called eutrophication.

Examples of some of the water pollutant and their descriptions: –

• Domestic sewage: Domestic sewage is also a major source of plant nutrients, mainly nitrates and phosphates. Excess nitrates and phosphates in water promote the growth of algae, sometimes causing unusually dense and rapid growths known as algal blooms.
• When the algae die, oxygen dissolved in the water declines because microorganisms use oxygen to digest algae during the process of decomposition. Solid waste:

• The improper disposal of solid waste is a major source of water pollution. Solid waste includes garbage, rubbish, electronic waste, trash, and construction and demolition waste, all of which are generated by individual, residential, commercial, institutional, and industrial activities.

• Fertilizers: causes water pollution from excessive amounts of nitrates and phosphate washed out from food and animal waste as well as inorganic fertilizers. Insecticides (pesticides) and herbicides: Insecticides (pesticides) and herbicides are applied in agriculture may also be washed into lakes, rivers, streams and seas. Some of the insecticides and herbicides do not decompose easily and are persistent in the environment.
• Lead: – This is a dangerous toxin found across the world, in fact, in all states. The element readily dissolves in water and upon uptake leads to devastating health problems

Methods of Reducing Water Pollution

• Treatment of water before discharge into rivers and lakes
• To avoid unnatural temperature changes in natural water systems, industries
• Should not discharge heat-ladened water into them.
• Recycling industrial and agricultural wastes.
• Using moderate amounts of agricultural chemicals and increasing the use of organic fertilizers and biological methods to control pests.

7.1.3. Land pollution

Land pollution is caused by things we put into it. It results from the spillage of oil, leaching of harmful chemicals and heavy metal ions, and dumping of non biodegradable wastes such as plastics.
Causes of Land Pollution

• Spillages of oil from leaking pipelines
• Harmful heavy metal ions from buried waste leaching into water systems.
• Leaching of harmful chemicals from corroded metal drums which have
• Been buried underground.
• Dumping of non-biodegradable (do not decompose by the action of bacteria)
• Wastes like plastics which remain unchanged in the soil for decades or
• Hundreds of years. Their accumulation in the soil hinders air and water
• Movement and affects the growth of plants.
• Excessive use of synthetic fertilizers in agricultural activities also contribute towards land pollution.
• What are the contributions of commercial inorganic fertilizers to land pollution?

What are the contributions of commercial inorganic fertilizers to land pollution?

Some of the pollutants that cause land pollution and their description:

Garbage: This is one of the significant land pollution causes. In every household, we will find garbage. Tons and tons of garbage are produced by typical and domestic households annually. When that massive amount gets generated, the disposal of it falls short. Consequently, all this garbage gets dumped onto the land. This land of disposal is known as a landfill.

Plastic: – This is one of the most common environmental pollutants and bears one of the greatest impacts. The abundance of plastics in the world even led to the coining of the term “plastic pollution.”
Mercury: – This element is released into the environment due to mining activities, poor disposal of certain items that are either made of mercury or had mercury in them.
Batteries are the main source of mercury, which is why it is essential to dispose of them carefully.

Methods of Reducing Land Pollution

• Reducing non-biodegradable wastes. This is because non-biodegradable wastes cannot be broken down by decomposers as a result their disposal poses a big problem.
• Non-biodegradable waste is a major source of soil, air, and water pollution. Besides, it’s cited as the primary cause of serious diseases such as cancer. The following are examples of non-biodegradable waste: glass, medical waste, Plastic, man-made synthetic materials, electronic components, cans, nuclear waste, manmade polymer and artificial rubber.

7.2. Global Warming and Climate Change

Change Global warming refers to the long-term increase in Earth’s average surface temperature due to human activities, especially the emission of greenhouse gases like carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O). These gases trap heat in the atmosphere, leading to a gradual rise in temperature.

Climate change encompasses not only global warming but also the broader range of changes affecting the Earth’s climate, including alterations in weather patterns, precipitation, sea levels, and the frequency and intensity of extreme weather events.

Causes of Global Warming

Green house Gas Emissions, Burning Fossil Fuels, The combustion of coal, oil, and natural gas for electricity, heat, and transportation release CO₂, the primary greenhouse gas contributing to global warming are;

• Deforestation: Cutting down forests reduces the number of trees that absorb CO₂, increasing its concentration in the atmosphere.
• Agriculture: Livestock farming releases large amounts of methane, a potent greenhouse gas. Fertilizer use also emits nitrous oxide.
• Industrial Processes: Certain chemical reactions used in manufacturing (e.g., cement production) release greenhouse gases.
• Waste Management: Decomposing organic waste in landfills releases methane.
• Effects of Global Warming rising Global Temperatures: Over the past century, Earth’s average surface temperature has risen by about 1.1°C. The temperature increase has been more pronounced in recent decades.
• Melting Ice and Snow: Glaciers and Ice Caps: Warming temperatures cause glaciers and polar ice caps to melt, contributing to sea level rise.
• Arctic Sea Ice: The Arctic region has been warming twice as fast as the global average, leading to the loss of sea ice and altering ecosystems.
• Rising Sea Levels: Melting ice and the thermal expansion of seawater (as water warms, it expands) lead to rising sea levels, which threaten coastal communities with flooding and erosion. Extreme Weather Events: Heatwaves: Higher temperatures increase the frequency and intensity of heatwaves.
• Droughts: Rising temperatures and changing precipitation patterns contribute to prolonged droughts in some regions.
• Heavy Rainfall and Flooding: Other regions may experience increased rainfall, leading to flooding and damage to infrastructure. Hurricanes and Storms: Warmer sea surface temperatures fuel more intense hurricanes and tropical storms.
• Ocean Acidification: The ocean absorbs about 30% of CO₂ emissions, leading to chemical reactions that increase ocean acidity. This harms marine life, particularly organisms with calcium carbonate shells, like corals and shellfish.
• Biodiversity Loss: Changes in temperature and weather patterns disrupt ecosystems, forcing species to migrate, adapt, or face extinction. Polar bears, for example, are threatened by the loss of sea ice in the Arctic.
• Impact on Agriculture: Climate change affects crop yields, with some regions experiencing more droughts and others facing heavy rains or unpredictable growing seasons. This can lead to food shortages and increased prices.
• Human Health Risks: Increased heat can lead to heatstroke, dehydration, and worsening of cardiovascular and respiratory diseases. Changing climate patterns also affect the spread of diseases like malaria and dengue.

What is Climate Change? While global warming refers specifically to the increase in Earth’s average temperature, climate change includes this warming but also encompasses all the other significant changes occurring in the climate system, such as: Changes in precipitation patterns. More frequent extreme weather events (e.g., hurricanes, droughts, floods).Shifts in climate zones, affecting ecosystems, agriculture, and human settlements.

• Main Drivers of Climate Change greenhouse Gas Emissions: The accumulation of greenhouse gases in the atmosphere leads to warming and climate shifts.
• Land Use Changes: Deforestation, urbanization, and agricultural expansion alter natural ecosystems, reducing the ability of forests and other vegetation to absorb CO₂.
• Aerosols and Particulates: Industrial and agricultural activities release aerosols that can have both warming and cooling effects on the climate. While some aerosols reflect sunlight and cool the Earth, others (like black carbon) absorb heat. Consequences of Climate Change altered Weather Patterns:
• Changing Rainfall Patterns: Some areas may experience more intense rainfall and flooding, while others suffer from prolonged droughts. More Frequent and Severe Storms: Warmer ocean temperatures provide energy for stronger storms and hurricanes. Impact on Ecosystems and Wildlife:
• Habitat Loss: As climate zones shift, many species may struggle to adapt or migrate, leading to reduced biodiversity and the extinction of some species.
• Ocean Ecosystems: Rising temperatures and acidification disrupt marine life, particularly coral reefs and fish populations.
• Social and Economic Impacts: Agricultural Disruptions: Shifting growing seasons and weather patterns reduce agricultural productivity in some areas, threatening food security.
• Migration and Conflict: Rising sea levels and extreme weather events may displace millions of people, leading to increased migration and potential conflicts over resources.
• Economic Costs: Climate change can damage infrastructure, reduce proud