Water Pollution

Water pollution occurs when the quality or composition of water changes, directly or indirectly, due to human activities, rendering it unfit for its intended purposes. Water pollution is classified into two types:

1. Point Source of Pollution: Pollution that can be traced to a specific origin, such as industrial discharge pipes or sewage outflows.
2. Non-Point Source of Pollution: Pollution from diffuse sources that cannot be easily identified, such as agricultural runoff, acid rain, and urban runoff.

Causes of Water Pollution

Surface Water Pollution:

• Disease-causing agents: Pathogens like bacteria, viruses, and protozoa from untreated sewage and waste.
• Oxygen-depleting wastes: Organic matter that bacteria break down, increasing Biochemical Oxygen Demand (BOD) and depleting oxygen, harming aquatic life.
• Inorganic plant nutrients: Water-soluble nitrates and phosphates from fertilizers and wastewater.
• Excess pesticides: Pesticides leaching into water bodies through runoff.
• Water-soluble organic chemicals: Toxins like mercury, lead, and other hazardous compounds.
• Suspended sediments: Soil erosion leads to sedimentation in water bodies.
• Radioactive isotopes: Pollutants entering water bodies through precipitation.
• Thermal pollution: Hot water discharge from industrial plants elevating water temperatures.
• Acid drainage: Acidic water draining into rivers due to mining operations.

Groundwater Pollution: Groundwater contamination poses a significant threat to human health, especially due to its use for drinking and irrigation. Common causes include:

• Urban runoff and untreated wastewater.
• Industrial waste storage near aquifers.
• Excessive use of fertilizers and pesticides in agriculture.
• Leaks from underground storage tanks.
• Leachate from landfills.
• Poor septic tank design and maintenance.
• Mining activities.

Effects of Water Pollution

1. Waterborne diseases: Contaminated water spreads diseases like diarrhea, typhoid, and cholera.
2. Oxygen depletion: Increased organic matter consumption by bacteria leads to oxygen depletion, suffocating aquatic life.
3. Eutrophication: Nutrient-rich pollutants (nitrates, phosphates) cause excessive algae growth, leading to oxygen depletion and the death of aquatic organisms.
4. Biomagnification: Excessive pesticide use accumulates up the food chain, affecting organisms at higher trophic levels.
5. Toxic chemicals: Organic and inorganic chemicals (such as acids, salts, heavy metals) make water unfit for consumption, harm aquatic life, and reduce crop yields.
6. Sedimentation: Erosion and suspended sediments clog water bodies, affecting aquatic habitats.
7. Radioactive contamination: Radioactive isotopes can cause genetic mutations, cancers, and birth defects.
8. Thermal pollution: Hot water discharge reduces oxygen solubility and disrupts aquatic organisms’ breeding cycles.
9. Oil spills: Accidental spills of oil or gasoline damage aquatic ecosystems.
10. Heavy metal poisoning: Conditions like mercury poisoning (Minamata disease), arsenic poisoning, and fluorosis from water contamination lead to various health issues.

Control Measures for Water Pollution

1. Effluent treatment plants: Treating wastewater to remove pollutants before discharge into water bodies.
2. Root zone process: Contaminated water is treated by running it through reed beds, where bacteria and fungi break down the waste.
3. Sanitation and wastewater facilities: Providing adequate sanitation systems to reduce the direct discharge of contaminants into water bodies.
4. Integrated Nutrient Management (INM) and Integrated Pest Management (IPM): Practices to reduce pesticide and fertilizer runoff into water bodies.