---
title: "Causes and control of soil pollution"
subject: "Engineering Chemistry"
chapter: 3
key: "semester_2/engineering_chemistry:soil-pollution"
source: https://www.bctengineer.com/q/semester_2/engineering_chemistry/soil-pollution
site: BCT Engineering
---

# Causes and control of soil pollution

Engineering Chemistry · Chapter 3: Environmental Chemistry

- Asked in: 2072 Asoj, 2 marks
- Video: [Soil Pollution| Causes/ Sources, Effects, Control/ Prevention| Soil Pollutants| Concepts of Botany](https://www.youtube.com/watch?v=Rz58_E67b2Q) — Concepts of Botany
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_2/engineering_chemistry/soil-pollution
- Whole chapter: https://www.bctengineer.com/md/semester_2/engineering_chemistry/chapter-3

## Question

What are the causes of soil pollution? How it can be controlled?

## Short answer

Causes include agrochemicals (fertilisers, pesticides), heavy metals (Pb, Hg, Cd), industrial wastes, and plastics. Control: organic farming, reduce/reuse/recycle, bioremediation, treatment of effluents, banning polythene, afforestation, and crop rotation.

## Answer

#### Causes of soil pollution
- **Agrochemicals:** chemical fertilisers (nitrates, phosphates), pesticides and herbicides (DDT, BHC, malathion).
- **Heavy metals:** Pb, Hg, Cd, As, Cr from mining, batteries, paints and industrial waste.
- **Industrial wastes:** fly ash, sludge, acids, alkalis, dyes, tannery waste.
- **Solid wastes:** plastics, polythene, glass, metal scrap, municipal garbage and e-waste.
- **Others:** sewage sludge, radioactive wastes, oil spills, acid rain deposition, excess salts from irrigation.

#### Control
- Use fertilisers and pesticides in controlled amounts; adopt organic farming, compost and biofertilisers, and integrated pest management.
- Segregate solid waste and follow reduce, reuse, recycle; compost biodegradable waste and produce biogas.
- Ban or limit polythene; use biodegradable materials.
- Treat industrial effluents before discharge; dispose of hazardous waste in secure landfills.
- Bioremediation and phytoremediation (microbes or plants that absorb metals) to clean polluted soil.
- Afforestation and crop rotation to prevent erosion; public awareness and strict laws.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Which are the agrochemical causes of soil pollution?
   A. Fly ash and sludge
   B. Chemical fertilisers (nitrates, phosphates), pesticides and herbicides such as DDT, BHC, malathion
   C. Pb, Hg, Cd from batteries
   D. Plastics and polythene
   Answer: B. Agrochemicals are fertilisers, pesticides and herbicides; the others are industrial wastes, heavy metals and solid wastes. (Key point: Agrochemicals)

2. Heavy-metal pollutants of soil (Pb, Hg, Cd, As, Cr) come mainly from
   A. organic farming and compost
   B. biofertilisers
   C. mining, batteries, paints and industrial waste
   D. crop rotation
   Answer: C. Mining, batteries, paints and industrial waste release heavy metals into soil. (Key point: Heavy metals)

3. Which practice helps control soil pollution from farming?
   A. Heavy use of chemical pesticides
   B. Burning polythene on the field
   C. Unlimited use of nitrogenous fertilisers
   D. Controlled use of fertilisers and pesticides, organic farming, compost, integrated pest management
   Answer: D. Reducing agrochemicals and using organic methods cuts chemical load on soil. (Key point: Agri control)

4. What is the recommended way to handle solid waste to protect soil?
   A. Segregate waste, reduce-reuse-recycle, compost biodegradables, limit polythene
   B. Bury all mixed waste in open dumps
   C. Mix plastics with compost
   D. Dump industrial waste untreated on land
   Answer: A. Segregation, 3R and composting reduce solid-waste load; polythene should be banned or limited. (Key point: Waste control)

## Related in Engineering Chemistry

- [Effects of soil pollution and its control](https://www.bctengineer.com/question.md?key=semester_2%2Fengineering_chemistry%3Asoil-effects-control) — 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×

## Related in other subjects

- [Air pollution: causes, effects and mitigation](https://www.bctengineer.com/question.md?key=semester_7%2Ftechnology_environment_and_society%3Aair-pollution-causes-mitigation) — Technology, Environment and Society, chapter 5, asked 3×
- [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
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- [Soil erosion causes and preventive measures](https://www.bctengineer.com/question.md?key=semester_6%2Ftransportation_engineering_i%3Aerosion-causes-prevention) — Transportation Engineering I, chapter 4