Environmental Pollution and Control

• A pollutant is anything released into the environment as a result of human activity that has the potential to cause harm
• Pollutants can be chemical substances (e.g., fertilizers, oil, carbon monoxide) or biological material (e.g., human body wastes)
• Heat from power stations and noise from industrial/domestic sources are also pollutants
• Pollution is the release of harmful substances into the environment from human activities

Domestic Wastes

• Washing powders and household detergents contain phosphate which is a plant nutrient, causing eutrophication
• Use of 'eco friendly' detergents without phosphate is a control method
• Improper sewage disposal causes eutrophication and increases the risk of diarrheal diseases
• Proper sewage disposal includes a drainage system and sewage treatment

Industrial Waste

• Carbon dioxide (from combustion of fossil fuels) is a greenhouse gas contributing to global warming
• Control: Energy efficiency measures can reduce demand for energy
• Sulphur dioxide (from combustion of high sulphur fuels) damages plants, forms acid rain and irritates the respiratory system
• Control: Use low sulphur fuels, remove sulphur dioxide from waste gases, and use catalytic converters
• Heavy metals (e.g., mercury and lead) accumulate in food chains and poison the human nervous system
• Control: Prevent release from factories
• PCBs accumulate in food chains
• Control: Use alternatives like electrical insulation

Agricultural Waste

• Herbicides kill non-target species, reducing biodiversity
• Pesticides kill non-target species, reducing biodiversity
• Control: Apply herbicides and pesticides more carefully or not at all
• Fertilizers runoff into water, causing eutrophication
• Control: Only apply when plants require fertilizers most
• Farmyard manure causes eutrophication and increases the risk of diarrheal diseases
• Control: Collect manure into pits for controlled decay (like in sewage works)
• Methane is emitted by anaerobic bacteria in flooded rice fields and by cattle
• Control: Grow strains of rice that do not need to be flooded

Water Pollution

• In the Caribbean, pollution ends up in the sea due to short rivers
• The Caribbean Sea is prone to pollution from ships and offshore oil rigs
• Oil pollution causes oil slicks, damaging coral reefs, seagrass, and beaches
• Sea birds are obvious victims, becoming coated in oil
• Chemical wastes from industry have devastating effects on natural environments
• PCBs and heavy metals are absorbed by small organisms like plankton
• These pollutants are not excreted, remain in bodies, and become concentrated in food chains
• High concentrations in top predators affect their physiology, reducing fertility

Air Pollution

• Some air pollutants remain near the ground, directly affecting humans and the environment
• Dust, dirt, exhaust fumes, and smoke cause deposits on buildings and plants
• Deposits on plants reduce photosynthesis and kill plants
• Sulphur dioxide (SO₂) and nitrogen oxides (NOₓ) react with water vapor to form sulphuric and nitric acids
• These acids return as acid rain, reacting with minerals in the soil
• Aluminium is mobilised by this reaction and damages plants and animal life
• Acid rain acidifies ponds, lakes, and rivers when falling on ground above granite, killing much of the aquatic life
• Gases like carbon dioxide and methane in the upper atmosphere prevent infrared radiation from reflecting into outer space
• This adds to the natural greenhouse effect and is called the enhanced greenhouse effect
• The overall effect is global warming, potentially leading to rising sea levels and unpredictable weather patterns