Effects of Pollution Chapter Notes | Geography Class 9 ICSE PDF Download

Pollution is like an uninvited guest that disrupts the balance of our environment, affecting air, water, soil, and even the invisible waves of radiation. It’s a topic that touches every corner of our planet, from the air we breathe to the water we drink and the land we walk on. Understanding the effects of pollution is crucial because it impacts not just nature, but also human health, animals, plants, and even man-made structures. This chapter, "Effects of Pollution," dives deep into how different types of pollution—air, water, soil, and radioactive—create a ripple effect, harming ecosystems and human life. With real-world examples like the Bhopal Gas Tragedy and Chernobyl Nuclear Disaster, we’ll explore why addressing pollution is not just a scientific concern but a call to protect our world for future generations.

Air Pollution and Its Effects

• Air pollution occurs when harmful gases or solid particles, like dust, contaminate the atmosphere.
• It affects the environment, human health, plants, animals, and even buildings and materials.

Effects of Air Pollution on the Environment

• Gases like carbon dioxide (CO₂), methane (CH₄), nitrogen dioxide (NO₂), and chlorofluorocarbons (CFCs) trap heat, causing global warming.
• Global warming leads to melting of ice in polar regions, raising sea levels.
• It increases evaporation of surface water, leading to soil erosion and loss of natural vegetation.
• Global warming can cause flooding, erosion, and salt buildup in delta regions.
• Example: The melting of polar ice caps due to global warming, caused by increased CO₂ levels from vehicle emissions, threatens coastal cities like Mumbai with flooding.

Effects of Air Pollution on Human Health

• Causes respiratory infections and irritation in eyes, nose, and throat.
• Leads to headaches, nausea, dizziness, and allergic reactions.
• Can result in chronic respiratory diseases, lung cancer, heart diseases, and damage to nerves, kidneys, and liver.

Effects of Air Pollution on Plants and Animals

• Nitrogen dioxide (NO₂) causes leaves to fall early and reduces crop yields by slowing plant growth.
• Ozone enters plant leaves through stomata, reacts with water and chemicals, damages leaves, and makes plants more vulnerable to diseases, pests, and droughts.
• Peroxyacetyl nitrate harms leafy vegetables, causing early leaf fall and discoloration.
• Sulphur dioxide (SO₂) bleaches plants, removes chlorophyll, and turns leafy vegetables yellow.
• Animals eating polluted plants may suffer from arsenic or lead poisoning, leading to bronchitis and loss of appetite.
• Air pollution damages painted surfaces, fabrics, and buildings, e.g., acid rain harms marble and limestone structures like the Taj Mahal.
• Sulphuric dioxide (SO₂) with moisture corrodes metals like steel, copper, and zinc.

Water Pollution and Its Effects

• Water pollution harms humans, plants, and animals, especially marine life, through processes like eutrophication and biomagnification.

Eutrophication

• Oxygen levels in water bodies decrease naturally or due to human activities like sewage and effluent discharge.
• Nutrients and chemicals in water cause excessive growth of phytoplankton and algae.
• This blocks sunlight and oxygen, leading to the death of aquatic organisms.

Example: In a lake receiving sewage, algae grow rapidly, covering the surface and preventing oxygen from reaching fish, causing their death.

Biomagnification

• Harmful substances like pesticides and insecticides build up in the food chain of marine organisms.
• These substances are consumed by other animals and humans, increasing toxicity levels.

Effects of Water Pollution on Human Health

• Pathogens in wastewater cause diseases like typhoid, cholera, diarrhoea, dysentery, and jaundice when contaminated water is consumed.
• Metals like lead, mercury, and cadmium in water cause diseases, e.g., cadmium caused itai-itai disease in Japan, and mercury caused Minamata disease from eating contaminated fish.

Other Effects of Water Pollution

• Phosphorus and nitrates from fertilizers promote algae growth, reducing dissolved oxygen and killing fish and aquatic organisms.
• Industrial effluents with mercury, lead, and cadmium cause irritation, insomnia, and nervous disorders when consumed through fish.
• Thermal pollution raises water temperature, lowering oxygen levels and killing fish species.
• Oil drilling and spills contaminate seawater, leading to the death of marine organisms.

Soil Pollution and Its Effects

• Soil pollution affects humans and animals through the food chain.

Effects of Soil Pollution

• Industrial effluents and chemical wastes pollute groundwater.
• Crops grown on polluted soil absorb toxins, passing them to animals and humans, causing chronic illnesses.
• Nitrogenous fertilizers create toxic levels of nitrate and nitrite preoccupations in leaves.
• Soil pollution reduces soil fertility, lowering agricultural productivity.

Example: Crops grown on soil contaminated with industrial chemicals absorb heavy metals, which, when consumed by humans, may lead to long-term health issues like kidney damage.

Effects of Soil Pollution on Human Health

• Polluted soil may contain pathogens, viruses, and intestinal worms, which enter humans through fruits and vegetables, causing various diseases.

Radioactive Pollution and Its Effects

• Caused by nuclear weapon testing, nuclear plants, and mining/refining of radioactive substances like uranium and thorium.

Effects of Radioactive Pollution on the Environment

• Radioactive wastes persist in the environment for a long time, causing long-term damage.
• Can discolor trees, e.g., pine forests near Chernobyl turned reddish-brown after the nuclear accident.
• Underground disposal of radioactive wastes may contaminate drinking water, harming plants, animals, and humans.

Effects of Radioactive Pollution on Human Health

• Radiations cause harmful changes in body cells and affect genes.
• Exposure can lead to genetic mutations passed to future generations.
• May cause lung cancer, brain cancer, thyroid cancer, sterility, and vision problems.

Effects of Radioactive Pollution through Food Chain

• Consuming animals that graze on plants grown in radioactive soil can cause organ abnormalities in humans.
• Human and animal excreta with pathogens can contaminate soil and crops, indirectly affecting human health.

Bhopal Gas Tragedy

• Occurred on December 2, 1984, in Bhopal, Madhya Pradesh, due to a leak of methyl-isocyanite (MIC) gas from the Union Carbide Plant.
• Caused around 3,500 deaths and affected 40,000 people over 100 km².
• Water entered MIC storage tanks, raising temperature and turning liquid MIC into gas.
• Caused by negligence in safety measures to cut costs, despite prior complaints about toxic leaks.
• Affected mostly poor working-class families, causing respiratory issues, eye problems, and damage to brain, kidneys, lungs, muscles, and reproductive health.
• Example: The Bhopal Gas Tragedy shows how neglecting safety in industrial plants can lead to massive loss of life and long-term health issues, as seen with the widespread respiratory and neurological damage caused by MIC exposure.

Chernobyl Nuclear Disaster

• Occurred on April 26, 1986, in Chernobyl, Ukraine, when a nuclear reactor exploded, releasing radioactive gases.
• Caused 64 immediate deaths, with long-term diseases affecting survivors and their offspring.
• Turned 4 km² of nearby pine forests reddish-brown, named "Red Forests," and killed or stunted animal growth.
• Radioactive clouds spread over Poland, Sweden, Germany, Norway, Finland, Italy, and France, contaminating water and soil.
• Nearby pine forests died gradually after turning reddish-brown.