--- title: "Organic/inorganic water pollutants, effects, remedies" subject: "Engineering Chemistry" chapter: 3 key: "semester_2/engineering_chemistry:water-pollution-substances-effects-remedies" source: https://www.bctengineer.com/q/semester_2/engineering_chemistry/water-pollution-substances-effects-remedies site: BCT Engineering --- # Organic/inorganic water pollutants, effects, remedies Engineering Chemistry · Chapter 3: Environmental Chemistry - Asked in: 2070 Magh, 3 marks; 2068 Bhadra, 3+2 marks (asked 2 times) - Video: [What Is Water Pollution | Environmental Chemistry | Chemistry | FuseSchool](https://www.youtube.com/watch?v=Zk1J2EW-nmQ) — FuseSchool - Global Education - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_2/engineering_chemistry/water-pollution-substances-effects-remedies - Whole chapter: https://www.bctengineer.com/md/semester_2/engineering_chemistry/chapter-3 ## Question Give an account on the sources of organic and inorganic substances responsible for water pollution with its adverse effect and possible remedies. ## Short answer Organic pollutants from sewage, farms, and industry cause oxygen depletion and disease; inorganic ones like heavy metals (Hg, Cd, Pb, As) and nitrates/phosphates cause toxicity, Minamata disease, arsenicosis, and eutrophication. Remedies: treat wastewater, use less fertiliser, enforce laws. ## Answer #### Sources of organic and inorganic water pollutants | Type | Pollutants | Source | |---|---|---| | Organic | Sewage, detergents, pesticides, oil, phenols, food waste | Households, farms, industries | | Inorganic | Heavy metals (Pb, Hg, Cd, As), nitrates, phosphates, acids, alkalis, salts | Industries, mines, fertilisers | | Biological | Bacteria, viruses, protozoa, worms | Sewage, animal waste | | Physical | Suspended solids, heat, radioactive material | Erosion, power plants | Sources in detail: domestic sewage and detergents; industrial effluents from tanneries, paper, textile, sugar and chemical mills; agricultural runoff of fertilisers and pesticides; mining and oil spills; solid waste dumping into rivers. #### Adverse effects - **Health:** waterborne diseases (cholera, typhoid, dysentery, hepatitis, diarrhoea); Hg causes Minamata disease, Cd causes itai-itai disease, As causes arsenicosis (found in groundwater of the Terai), Pb damages the brain; nitrate in water causes blue-baby syndrome. - **Eutrophication:** excess nitrate and phosphate cause algal blooms; when the algae die, their decay uses up dissolved oxygen (high BOD, low DO) and fish die. - **Bioaccumulation and biomagnification** of pesticides and metals in the food chain. - Bad taste, smell and colour; water is unfit for drinking, irrigation and industry. - Thermal pollution reduces oxygen solubility and disturbs aquatic life. #### Possible remedies - Treat sewage and industrial effluents before discharge (primary, secondary and tertiary treatment). - Use less fertiliser and pesticide; use organic farming; ban phosphate detergents. - Prevent dumping of solid waste in rivers; build proper sanitation and toilets. - Cool hot water before discharge; recycle and reuse water. - Strict laws (polluter pays), regular monitoring, public awareness and river-cleaning programmes (such as for the Bagmati). ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. Which are inorganic water pollutants? A. Sewage, detergents and pesticides B. Bacteria and viruses C. Suspended solids and heat D. Heavy metals, nitrates, phosphates, acids, alkalis, salts Answer: D. The others are organic, biological and physical pollutants. (Key point: Inorganic pollutants) 2. How does excess nitrate and phosphate in a lake kill fish? A. They cause algal bloom; on decay the algae use up dissolved oxygen (high BOD, low DO) B. They make the water too alkaline for fish gills C. They directly poison fish with nitrate crystals D. They raise dissolved oxygen so much that fish burst Answer: A. Nutrients cause algal bloom; decay of the algae consumes dissolved oxygen, so fish suffocate. (Key point: Eutrophication) 3. Which pairing of pollutant and disease is correct? A. Hg - itai-itai disease; Cd - Minamata disease B. Hg - Minamata disease; Cd - itai-itai disease C. As - Minamata disease; Pb - arsenicosis D. Cd - blue-baby syndrome; Hg - arsenicosis Answer: B. Mercury causes Minamata disease and cadmium causes itai-itai disease; arsenic causes arsenicosis and nitrate causes blue-baby syndrome. (Key point: Metal diseases) 4. Which is a key remedy for water pollution from sewage and industry? A. Discharge them directly into rivers so they dilute B. Add more phosphate detergents C. Treat sewage and industrial effluents (primary, secondary, tertiary) before discharge D. Dump solid waste into rivers so it settles Answer: C. Treating effluents before discharge removes pollutants at the source. (Key point: Effluent treatment) ## Related in Engineering Chemistry - [Water pollution, pollutants and adverse effects](https://www.bctengineer.com/question.md?key=semester_2%2Fengineering_chemistry%3Awater-pollutants-effects) — Engineering Chemistry, chapter 3 - [Sources, effects and remedies of water pollution](https://www.bctengineer.com/question.md?key=semester_2%2Fengineering_chemistry%3Awater-pollution-sources) — Engineering Chemistry, chapter 3, asked 2× - [Air pollution, pollutants, sources and remedies](https://www.bctengineer.com/question.md?key=semester_2%2Fengineering_chemistry%3Aair-pollution-sources-remedies) — Engineering Chemistry, chapter 3 - [Soil pollutants, effects and remedies](https://www.bctengineer.com/question.md?key=semester_2%2Fengineering_chemistry%3Asoil-pollutants-effects-remedies) — Engineering Chemistry, chapter 3, asked 5× - [Air pollutants: effects and remedies](https://www.bctengineer.com/question.md?key=semester_2%2Fengineering_chemistry%3Aair-pollutants-effects) — Engineering Chemistry, chapter 3 - [Water pollutants, harmful effects, control measures](https://www.bctengineer.com/question.md?key=semester_2%2Fengineering_chemistry%3Awater-pollutants-effects-measures) — Engineering Chemistry, chapter 3 ## Related in other subjects - [Water pollution: sources and effects](https://www.bctengineer.com/question.md?key=semester_7%2Fenvironment_and_pollution_control%3Awater-pollution-sources-effects) — Environment and Pollution Control, chapter 4 - [Particulate pollutants: sources and effects](https://www.bctengineer.com/question.md?key=semester_7%2Fenvironment_and_pollution_control%3Aparticulate-pollutants-sources-effects) — Environment and Pollution Control, chapter 1 - [Inorganic water pollution in Nepal](https://www.bctengineer.com/question.md?key=semester_7%2Ftechnology_environment_and_society%3Ainorganic-water-pollution-nepal) — Technology, Environment and Society, chapter 5 - [Water pollution: sources, causes and impacts](https://www.bctengineer.com/question.md?key=semester_7%2Ftechnology_environment_and_society%3Awater-pollution-sources-impacts) — Technology, Environment and Society, chapter 5