Biodegradable and Non-Biodegradable Substances
Complete Notes for Competitive Examinations
Definition, Examples, Properties, Differences, Environmental Effects and MCQs
By Home Academy
1. Introduction
Materials present in the environment can be classified into:
Biodegradable substances
Non-biodegradable substances
This classification is based on whether microorganisms can decompose them or not.
2. Biodegradable Substances
Definition
Substances that can be broken down into simpler harmless substances by microorganisms such as:
Bacteria
Fungi
are called biodegradable substances.
Important Point
They decompose naturally in environment.
Examples of Biodegradable Substances
| Substance | Example |
|---|---|
| Plant waste | Leaves |
| Animal waste | Cow dung |
| Food waste | Vegetable peels |
| Natural fibers | Cotton, jute |
| Paper | Newspaper |
Characteristics of Biodegradable Substances
| Property | Description |
|---|---|
| Easily decomposed | By microorganisms |
| Eco-friendly | Less pollution |
| Natural origin | Mostly organic |
| Short life in environment | Decompose quickly |
Decomposition Process
Organic\ Waste \rightarrow Microorganisms \rightarrow Simpler\ Substances
Advantages of Biodegradable Substances
Reduce pollution
Recycle nutrientsEnvironment friendly
Useful in compost formation
3. Non-Biodegradable Substances
Definition
Substances that cannot be decomposed easily by microorganisms are called non-biodegradable substances.
Important Point
They remain in environment for long periods.
Examples of Non-Biodegradable Substances
| Substance | Example |
|---|---|
| Plastic | Polythene bags |
| Glass | Bottles |
| Metals | Aluminium cans |
| Synthetic fibers | Nylon |
| Pesticides | DDT |
Characteristics of Non-Biodegradable Substances
| Property | Description |
|---|---|
| Not decomposed easily | Persist for long time |
| Cause pollution | Environmental hazard |
| Mostly synthetic | Artificial origin |
| Accumulate in environment | Harmful effects |
Harmful Effects of Non-Biodegradable Waste
Soil pollution
Water pollutionAir pollution
Harm to animals
Biomagnification
4. Biomagnification
Definition
Increase in concentration of harmful non-biodegradable substances along food chain.
Important Example
DDT accumulation in food chain.
Important Concept
Small\ Organism \rightarrow Fish \rightarrow Bird \rightarrow Increased\ Toxin\ Concentration
5. Difference Between Biodegradable and Non-Biodegradable Substances
| Biodegradable | Non-Biodegradable |
|---|---|
| Decomposed by microorganisms | Not decomposed easily |
| Environment friendly | Polluting |
| Natural substances | Mostly synthetic |
| Short environmental life | Persist for long time |
| Example: Paper | Example: Plastic |
6. Methods to Manage Non-Biodegradable Waste
| Method | Purpose |
|---|---|
| Recycling | Reuse materials |
| Reusing | Reduce waste |
| Reducing plastic use | Environmental protection |
7. Importance of Biodegradable Waste
Biodegradable waste can be converted into:
Compost
BiogasOrganic manure
Example
Cow dung → Biogas production
8. Environmental Impact
Biodegradable Waste
Positive Effects
Natural recycling
Less pollutionNegative Effects
Produces foul smell if unmanagedNon-Biodegradable Waste
Negative Effects
Land pollution
Water contaminationHarmful to wildlife
9. Important Exam Points
Biodegradable substances decompose naturally.
Non-biodegradable substances persist for long time.Plastic is non-biodegradable.
Paper is biodegradable.
DDT causes biomagnification.
Microorganisms decompose biodegradable waste.
Recycling reduces non-biodegradable waste pollution.
10. Frequently Asked MCQs
1. Which of the following is biodegradable?
A. Plastic
B. Glass
C. Paper
D. Nylon
✅ Answer: C
2. Which of the following is non-biodegradable?
A. Vegetable peel
B. Cotton
C. Plastic
D. Cow dung
✅ Answer: C
3. Biomagnification is associated with:
A. Oxygen
B. Water vapor
C. DDT
D. Nitrogen
✅ Answer: C
4. Which organisms decompose biodegradable waste?
A. Birds
B. Microorganisms
C. Mammals
D. Reptiles
✅ Answer: B
5. Which of the following causes long-term pollution?
A. Leaves
B. Food waste
C. Plastic
D. Cotton
✅ Answer: C
11. Fact-Based Questions
Question 1
Consider the following statements:
Paper is biodegradable.
Plastic is non-biodegradable.
Biodegradable substances are decomposed by microorganisms.
A. Only 1 and 2
B. Only 2 and 3
C. 1, 2 and 3
D. Only 1 and 3
✅ Answer: C
Question 2
Which of the following are biodegradable?
Cotton
Food waste
Leaves
A. Only 1 and 2
B. Only 2 and 3
C. 1, 2 and 3
D. Only 1 and 3
✅ Answer: C
Question 3
Consider the following:
Plastic causes environmental pollution.
DDT is non-biodegradable.
Recycling helps reduce waste pollution.
A. Only 1 and 2
B. Only 2 and 3
C. 1, 2 and 3
D. Only 1 and 3
✅ Answer: C
12. Assertion–Reason Questions
Assertion (A)
Plastic is harmful to environment.
Reason (R)
Plastic is non-biodegradable and persists for long periods.
A. Both A and R are true and R explains A
B. Both true but R not explanation
C. A true, R false
D. A false, R true
✅ Answer: A
Assertion (A)
Biodegradable waste is environment friendly.
Reason (R)
It can be decomposed naturally by microorganisms.
A. Both A and R are true and R explains A
B. Both true but R not explanation
C. A true, R false
D. A false, R true
✅ Answer: A
13. Previous Year Type Questions (PYQs)
PYQ 1
Which of the following is biodegradable?
A. Plastic bag
B. Glass bottle
C. Cotton cloth
D. Aluminium can
✅ Answer: C
PYQ 2
Non-biodegradable substances:
A. Decompose quickly
B. Are harmless
C. Persist in environment for long time
D. Improve soil fertility
✅ Answer: C
PYQ 3
The process of increase in concentration of toxic substances along food chain is:
A. Photosynthesis
B. Respiration
C. Biomagnification
D. Fermentation
✅ Answer: C
14. Quick Revision Table
| Topic | Important Fact |
|---|---|
| Biodegradable waste | Decomposed by microbes |
| Non-biodegradable waste | Persistent pollutants |
| Example biodegradable | Paper |
| Example non-biodegradable | Plastic |
| Toxic accumulation | Biomagnification |
15. One-Liner Revision
| Question | Answer |
|---|---|
| Substance decomposed naturally | Biodegradable |
| Substance not decomposed easily | Non-biodegradable |
| Example biodegradable | Leaves |
| Example non-biodegradable | Plastic |
| Organisms decomposing waste | Microorganisms |
| Harmful accumulation in food chain | Biomagnification |
Conclusion
Biodegradable and non-biodegradable substances differ in their ability to decompose naturally. Biodegradable materials are eco-friendly, while non-biodegradable materials cause long-term environmental pollution. Understanding their properties, examples, environmental impacts, and waste management methods is essential for competitive examinations and environmental awareness.
Prepared By Home Academy