What is Eutrophication?
Eutrophication is the process by which a water body (lake, river, pond, or coastal area) becomes over-enriched with nutrients, mainly nitrogen and phosphorus, leading to excessive growth of algae and aquatic plants.
Causes of Eutrophication
1. Agricultural runoff
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Excess use of chemical fertilizers rich in nitrogen and phosphorus
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Runoff during rains carries nutrients into nearby water bodies
Examples:
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Fertilizer runoff into lakes and reservoirs
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Green Revolution–intensive farming regions
2. Domestic sewage discharge
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Untreated or partially treated sewage contains high nutrients.
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Major source in urban and peri-urban areas
Examples:
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Sewage inflow into rivers, lakes, and urban tanks
3. Industrial effluents
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Discharge nutrient-rich wastewater
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Food processing, paper, textile, and fertilizer industries
Examples:
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Effluents entering rivers and coastal waters.
4. Detergents and household chemicals
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Phosphate-based detergents add nutrients to water bodies
Examples:
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Washing activities near rivers and lakes
5. Urban runoff
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Stormwater carries nutrients from roads, gardens, and waste dumps
Examples:
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City drains emptying into lakes
6. Aquaculture and livestock waste
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Fish farms and animal wastes add organic matter and nutrients
Examples:
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Intensive fish farming in reservoirs
7. Natural causes
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Weathering of rocks
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Natural decay of vegetation
Examples:
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Gradual nutrient accumulation in old lakes
Way Forward to Control Eutrophication
1. Control nutrient input at source
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Reduce excessive use of chemical fertilizers.
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Promote balanced fertilization and soil testing.
Examples:
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Precision farming, organic manure use
2. Improve sewage treatment
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Ensure 100% treatment of urban and rural sewage
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Upgrade STPs for nutrient (N & P) removal
Examples:
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Tertiary treatment, constructed wetlands
3. Regulate industrial discharge
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Strict enforcement of effluent standards
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Zero liquid discharge where feasible
Examples:
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Continuous effluent monitoring systems
4. Eco-friendly detergents
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Ban or limit phosphate-based detergents
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Promote biodegradable alternatives
Examples:
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Low-phosphate household cleaners
5. Watershed and buffer management
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Create vegetative buffer strips along water bodies
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Prevent direct runoff entry
Examples:
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Riparian vegetation belts
6. Lake and wetland restoration
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Desilting, aeration, bioremediation
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Revival of natural wetlands as nutrient sinks
Examples:
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Artificial aerators, floating wetlands
7. Policy, awareness, and monitoring
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Integrated lake basin management
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Public awareness and community participation
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Regular water quality monitoring
