Water and Air Pollution: Sources, Impacts, and Mitigation
Water Pollution
BOD and Eutrophication
BOD (Biological Oxygen Demand): BOD indicates the level of organic pollution in water. Eutrophication occurs when inland waters are contaminated with excessive organic substances. These pollutants, often from discharges, lead to a high concentration of organic nutrients. As these nutrients degrade into inorganic substances, they consume significant oxygen, negatively impacting aquatic life, ecosystems, and water quality.
Wastewater Treatment
Debugging: Two primary purification systems address wastewater:
- Natural Purification Systems: Lagoons and green filters are suitable for relatively low wastewater volumes with low organic pollution loads.
- Sewage Treatment Plants: For larger wastewater volumes and higher pollution loads, more efficient treatment mechanisms are necessary.
Salinization
Salinization is a significant groundwater contamination process, primarily caused by:
- Saltwater Intrusion: In areas with frequent artificial irrigation, salt leakage from irrigation water can contaminate groundwater. Evaporation further concentrates the salts.
- Coastal Water Extraction: Extracting freshwater from wells near coastlines can lead to saltwater intrusion into the aquifer.
Sources of Pollution
Natural Sources
Natural processes contribute to pollution through:
- Volcanic eruptions (sulfur compounds, particulate matter)
- Respiration of living organisms (CO2)
- Decomposition of organic matter (CH4)
- Forest fires (CO2, CO)
Artificial (Man-Made) Sources
Since the Industrial Revolution, human activities have become major pollution contributors:
- Fossil fuel use (gas, oil, coal) generating significant particulate matter
- Household activities
- Transportation
- Industrial processes
- Agriculture and livestock farming
- Waste burning
Marine Pollution
Sources of Marine Pollution
Marine pollution originates from various sources:
- Sewage and garbage, including plastics that endanger marine life
- Radioactive waste (plutonium, cesium, mercury)
- Nuclear weapons and submarines
- Air pollution contributing to one-third of total marine pollution
- Agricultural fertilizers causing eutrophication in river deltas
- Ship and oil platform exhaust
- Oil spills (oil slicks)
Impacts of Oil Spills
- Thermal insulation, affecting marine animals’ buoyancy and insulation
- Reduced light penetration, hindering photosynthesis
- Toxicity, poisoning marine life
- Disruption of fishing and tourism
- Destruction of marine and coastal ecosystems
Air Pollution
Thermal Inversion and Pollution Dispersion
Thermal inversion occurs when a layer of warm air traps colder air near the ground, preventing pollutant dispersion. This phenomenon is common in valleys, where cold air settles at night and is trapped by warmer air above during the day.
Smog
Smog is a type of air pollution that forms when fog mixes with pollutants. Photochemical smog, a specific type, results from the reaction of nitrogen oxides with volatile organic compounds in the presence of sunlight. This reaction produces ground-level ozone and other harmful pollutants that can damage the respiratory systems of humans and animals.
Air Pollution Definition and Sources
According to the World Health Organization (WHO), air pollution is the presence of substances or energies in the air at levels that pose risks, harm, or significant nuisance to humans, animals, and the environment. These pollutants can originate from various sources, including industrial emissions, vehicle exhaust, and natural events like volcanic eruptions.
Water Pollutants
Types of Water Pollutants
Water pollutants encompass a wide range of substances and organisms:
- Microorganisms and Pathogens: Bacteria, viruses, and protozoa can contaminate water sources and spread diseases.
- Organic Waste: Decomposed by aerobic bacteria, consuming oxygen and depleting levels necessary for aquatic life.
- Inorganic Chemicals: Acids, heavy metals (mercury, lead), and other inorganic pollutants can be toxic to humans, animals, and plants.