Class 10 Our Environment
INTRODUCTION
In simple terms, our surrounding is called the environment. But the word ‘environment’ has much deeper meaning and its scope is much wider than what most of us think. Our life totally depends on our environment; in this includes not only the immediate environment but the environment of the whole world. In this lesson, you will learn about the various factors which make an environment the hub of life. You will learn about various interactions which take place in the environment. Human beings; by virtue of being the most intelligent species; have been impacting the environment because of their various activities. While some of the effects may be good for the environment, many activities have a deleterious effect on the environment. You will read about the impact of human activities on the environment.
“The biotic and abiotic surrounding
Effect of Waste on Environment
During our day to day activities, we generate a lot of waste. As per normal rules of the functioning of the environment; most of these materials should be channelled back into the environment through various biogeochemical cycles. You may recall what you read about biogeochemical cycles in your previous class. The cycle through which various materials are recycled back into the environment from the living world is called biogeochemical cycle. Carbon cycle, nitrogen cycle, oxygen cycle, etc. are some examples of biogeochemical cycles. However, this may not be possible with many of the waste which we produce.
Biodegradable Substance: A substance which can be broken down through the biological process is called a biodegradable substance. The organic substances are generally biodegradable in nature, e.g. leftover food, vegetable and fruit peels, tea leaves, paper, cloth, etc. However, the rate of degradation can be different for different substances. While fruit and vegetable peels can get decomposed within a fortnight, paper can take many months for that. On the other hand, the cloth may take many years to get decomposed.
Non-biodegradable Substance: A substance which cannot be cannot be broken down is called a non-biodegradable substance. The inorganic substances and many synthetic substances are non-biodegradable in nature, e.g. aluminium, plastic, iron, copper, glass, ceramic, etc. These substances would remain to lie at a garbage dump for thousands of years.
Apart from producing many waste materials of organic origin, we also produce a lot of waste which is of inorganic origin. Even some of the organic substances are now synthetic, i.e. they are made in factories. Plastic and synthetic fibre are examples of such substances. These are non-biodegradable substances and hence shall accumulate in nature.
It is the accumulation of non-biodegradable substances which is a big concern for all of us. For example; plastic is a very useful substance and hence has been very popular for various uses. But we are generating too much of plastic waste which goes on accumulating in our environment. Plastic bags can choke the drainage. It can turn the soil of an area infertile.
| Approximate time to biodegrade in the marine environment | |
| Product | Time to biodegrade |
| Paper towel | 2 – 4 weeks |
| Newspaper | 6 weeks |
| Apple core | 2 months |
| Cardboard box | 2 months |
| Wax coated milk carton | 3 months |
| Cotton gloves | 1 – 5 months |
| Wool gloves | 1 year |
| Plywood | 1 – 3 years |
| Painted wooden sticks | 13 years |
| Plastic bags | 10 – 20 years |
| Tin cans | 50 years |
| Plastic bottle | 100 years |
| Aluminium cans | 200 years |
| Glass bottle | Undetermined |
Important Note: Nowadays, biodegradable plastic is being used by many companies for packaging. Biodegradable plastic is more environment-friendly compared to conventional plastic. Biodegradable plastic is either made from renewable raw materials or by using biodegradable additives with conventional plastic.
Example: Give any two ways in which biodegradable substances would affect the environment. (NCERT)
Solution: Biodegradable substances would affect the environment in following two ways:
- Positive Effect: They will help in recycling various materials into the environment.
- Negative Effect: The process of biodegradation results in bad stench all around. A heap of biodegradable substance may spread certain epidemics.
Example: Give any two ways in which non-biodegradable substances would affect the environment. (NCERT)
Solution: Non-biodegradable substances would affect the environment in following two ways:
- Positive Effect: Many non-biodegradable substances can be recycled many times to make useful products. This helps in reducing the drain of natural resources.
- Negative Effect: Accumulation of non-biodegradable waste is a huge concern for the environment.
EXERCISE 15.1
Very Short Answer Type Questions:
- What is environment?
Answer: The biotic and abiotic surrounding of an organism or a population is called the environment for that organism or population.
- What is a biogeochemical cycle?
Answer: The natural cycle through which various materials are cycled in the environment is called biogeochemical cycle.
- Give five examples of biodegradable substance.
Answer: Fruit and vegetable peels, paper, cotton cloth, wood, leftover food and used tea leaves.
Write True/False for the following:
- Vegetable and fruit peels take less time for biodegradation. (T)
- Cotton is biodegradable, while wool is not. (F)
- Glass can be recycled many times. (T)
- None of the object made of plastic can be recycled. (F)
Short Answer Type Questions:
- What is the difference between biodegradable and non-biodegradable substances?
Answer:
| Biodegradable | Non-biodegradable |
| These substances can be degraded through biological processes. | These substances cannot be degraded through biological processes. |
| Most of them do not accumulate in the environment. | Most of them do accumulate in the environment. |
| Examples: Fruit peels, leftover food, paper, etc. | Examples: aluminium can, plastic bottle, etc. |
- State some disadvantages of plastic bags.
Answer: Following are the disadvantages of plastic bags:
- Plastic bags are non-biodegradable and hence they keep on accumulating in the environment.
- A plastic bag can turn the soil infertile.
- A plastic bag can choke the drains.
- Stray animals can die after swallowing plastic bags.
- The burning of plastic bags creates noxious fumes.
- Plastic bags can be fire hazards.
Multiple Choice Questions
- Which of the following is biodegradable?
- Bamboo basket
- Nylon rope
- Plastic bag
- Silver foil
Answer: (a) Bamboo basket
- Which of the following is non-biodegradable?
- Paper napkin
- Compact Disc
- Cotton swabs
- Jute bag
Answer: (b) Compact Disc
Brainstorming Session
- Why are some substances biodegradable and some non-biodegradable? (NCERT)
Answer: To be biodegradable, it is necessary that a given substance can be degraded by the enzymes secreted by decomposers. Substances which can be acted upon by such enzymes are biodegradable, while others are non-biodegradable.