Environmental Chemistry: Pollution and Conservation - SS3 Chemistry Past Questions and Answers - page 4

Sources and Major Types of Water Pollution:

Water pollution occurs due to the discharge of various pollutants into water bodies. The major types of water pollution include:

1.    Point Source Pollution: Sources: Point source pollution originates from identifiable and specific sources, such as industrial discharges and sewage treatment plants.

2.    Non-Point Source Pollution: Sources: Non-point source pollution comes from diffuse sources, like agricultural runoff, urban stormwater, and atmospheric deposition.

3.    Nutrient Pollution: Sources: Nutrient pollution arises from excess nutrients, mainly nitrogen and phosphorus, from agricultural activities, wastewater discharges, and fertilisers.

4.    Organic Pollution: Sources: Organic pollution results from the discharge of biodegradable materials, like untreated sewage and agricultural waste.

5.    Toxic Pollution: Sources: Toxic pollutants are released from industrial discharges, improper waste disposal, and the use of pesticides and other toxic chemicals.

Environmental and Public Health Impacts of Water Pollution:

1.    Environmental Impacts:

●     Water pollution disrupts aquatic ecosystems, leading to declines in biodiversity and the loss of aquatic species.

●     Excess nutrients cause eutrophication, leading to algal blooms, oxygen depletion, and dead zones in water bodies.

●     Toxic pollutants harm aquatic life and accumulate in the food chain, affecting higher trophic levels.

2.    Public Health Impacts:

●     Contaminated water poses health risks to humans through the ingestion of pathogens and toxic substances.

●     Waterborne diseases, such as cholera and gastrointestinal infections, are prevalent in areas with polluted water sources.

●     Exposure to polluted water can lead to long-term health issues, including cancer and neurological disorders.

The Chemistry behind Water Pollutant Formation and Effects:

1.    Formation of Nutrient Pollution: Excess nitrogen and phosphorus from fertilisers, sewage, and agricultural runoff lead to the eutrophication of water bodies. Nutrient enrichment fuels algal growth, resulting in harmful algal blooms and oxygen depletion.

2.    Formation of Organic Pollution: Untreated sewage and agricultural runoff introduce organic matter into water bodies. This organic matter undergoes microbial decomposition, leading to oxygen depletion and harming aquatic life.

3.    Formation of Toxic Pollution: Industrial discharges and improper waste disposal introduce toxic substances, such as heavy metals and pesticides, into water bodies. These toxic pollutants can accumulate in the food chain, causing bioaccumulation and biomagnification.

Water Pollution Control and Wastewater Treatment:

1.    Regulatory Measures: Governments implement water quality standards and regulations to limit pollutant discharges and control water pollution.

2.    Wastewater Treatment: Wastewater treatment plants remove pollutants from sewage and industrial discharges through physical, chemical, and biological processes.

3.    Best Management Practices: Implementing best management practices in agriculture and urban planning can reduce nonpoint source pollution.

4.    Nutrient Management: Proper nutrient management practices in agriculture help minimise nutrient runoff and eutrophication.

By addressing water pollution through effective control measures and wastewater treatment, we can safeguard aquatic ecosystems and protect public health. Proper management of pollution sources and sustainable practices are essential for ensuring clean and safe water resources for current and future generations.