NIOS Class 12 Environmental Science Chapter 11 Environment And Health

NIOS Class 12 Environmental Science Chapter 11 Environment And Health Solutions to each chapter is provided in the list so that you can easily browse throughout different chapters NIOS Class 12 Environmental Science Chapter 11 Environment And Health Notes and select need one. NIOS Class 12 Environmental Science Chapter 11 Environment And Health Question Answers Download PDF. NIOS Study Material of Class 12 Environmental Science Paper Code 333.

NIOS Class 12 Environmental Science Chapter 11 Environment And Health

Also, you can read the NIOS book online in these sections Solutions by Expert Teachers as per National Institute of Open Schooling (NIOS) Book guidelines. These solutions are part of NIOS All Subject Solutions. Here we have given NIOS Class 12 Environmental Science Chapter 11 Environment And Health Solutions, NIOS Senior Secondary Course Environmental Science Solutions for All Chapter, You can practice these here.

Environment And Health

Chapter: 11

Module 4: Contemporary Environment issues

Textual Question Answer

INTEXT QUESTIONS 11.1

1. Define health.

Ans: Health of a person is the result of interaction of a large number of influences upon the person.

2. What is the advantage of providing potable water (drinking water) to the community?

Ans: To prevent for spreading many water borne diseases.

3. What are slums?

Ans: Slums are unplanned aggregations of hutments arranged very closely without any space for roads, parks, drains etc.

4. State any two reasons for health problems in villages?

Ans: Lack of safe drinking water supply, improper disposal of excreta, high infant mortality any other).

INTEXT QUESTIONS 11.2

1. State one example of disease transmitted by vector.

Ans: Malaria, yellow fever, encephalitis (any one).

2. Diarrhoea with or without blood or mucous in stools, fever and gripping pain in abdomen are all symptoms of a water borne element. Name it.

Ans: Bacterial dysentery.

3. Name the bacteria which causes Leptospirosis.

Ans: Leptospira.

INTEXT QUESTIONS 11.3

1. From which industries are foul smelling gases released.

Ans: Sugar mills and tanneries industries.

2. Which air pollutant is released from stone quarries and iron mines?

Ans: Suspended particulate matter.

3. In congested townships movement of traffic on dusty roads, smoke from industries and diesel vehicles result, a pollutant gathers in air. Which pollutant is it? 

Ans: Oxides of sulphurs, oxides of nitrogen, hydrocarbons, carbon monoxide, carbon dioxide.

4. List the major pollutants in agricultural areas.

Ans: Ammonia, pesticides smoke and water vapour.

INTEXT QUESTIONS 11.4

1. Name three pesticides which are known to cause lymphatic cancer in rats and mice.

Ans: Toxaphene/hexachlor cyclo hexane – HCH, BHC, dieldrin DDT (any three)

2. What measures can be taken to minimise the incidence of skin cancer? 

Ans: Clothing cover hands and feet, weary of broad. brimmed using of sunglasses.

3. What are the possible programs which can be taken up to minimise damage from pesticides? 

Ans: Organic farming and Integrated Pest Management (IPM).

4. What is the cause of the Blue Baby Disease? 

Ans: Elevated levels of nitrates in ground water.

5. Give two major symptoms of Asthma.

Ans: Shorten of breathe, wheezing, chest lightness, pain around the chest, persistent cough that can last several weeks (any two).

INTEXT QUESTIONS 11.5

1. What is heavy metal toxicity? 

Ans: Toxic metal are dispersed in the environmental through industrial effluents burning of organic wastes, transport and power generation. It may endanger public health after being incorporated in food chain.

2. State two symptoms of arsenic poisoning due to consumption of groundwater containing arsenic.

Ans: Loss of appetite and skin cancer.

3. Mention the form in which mercury acts as a poison.

Ans: Methyl mercury.

4. Which metal does battery scrap leave in the environment? 

Ans: Lead (Tetraethyl lead TEL).

INTEXT QUESTIONS 11.6

1. Which workers are involved with heavy physical work? 

Ans: Miners, lumberjacks, construction workers, formers, fishermen, storage workers and health care personnel.

2. What kind of problem does sound level of 120 dB for a few hour may lead to? 

Ans: Annoyance, temporary hearing loss, disturbed sleep.

3. State any two symptoms of long exposure to noise pollution? 

Ans: Auditory fatigue and giddiness.

TERMINAL EXERCISE

1. What are some of the sanitary problems in villages?

Ans: Sanitary problems in villages arise mainly due to poor infrastructure and lack of awareness. 

Some of the major issues are:

(i) Lack of proper toilets: Absence of household or community toilets leads to open defecation, which contaminates soil and water and spreads diseases.

(ii) Improper disposal of waste: Human and animal waste often gets mixed with stagnant water, creating unhygienic conditions.

(iii) Polluted water sources: Livestock often enter village ponds or wells, making drinking water unsafe.

(iv) Open drains and stagnant water: Leads to foul smell, mosquito breeding, and spread of water-borne diseases.

(v) Lack of waste management: Garbage and organic waste remain unattended, worsening the sanitary condition.

2. Describe the transmission of the following diseases – Typhoid, Filaria (Elephantiasis), and Amoebic dysentery. What is the causative organism for each of these diseases?

Ans: Bacterial Disease: Typhoid.

Causative organism: Salmonella typhi.

Mode of spread: Contaminated food, water, milk, unwashed raw vegetables, and flies.

Symptoms: Continuous fever which increases day by day. Temperature higher in the evening than morning, body ache, headache, and constipation.

Hemorrhage from ulceration in the small intestine.

Vector-borne disease: Fllarla (Elephantiasis).

Causative organism: Wuchereria.

Vector: Culex fatigans.

Hosts: Man.

Symptoms: Enlargement of limbs and scrotum.

Protozoan disease: Amoebic dysentery.

Causative organism: Entamoeba histolytica.

Mode of spread: Ingestion of cysts in food and water.

Symptoms: Abdominal disorders leading to epigastric pain, abdominal discomfort, loss of appetite, headache and loose bowels.

3. Describe a disease often prevalent in coal miners working for many years. State the measures required to control it.

Ans: Coal miners who work for many years are often affected by a lung disease known as Black Lung Disease or Coal Workers’ Pneumoconiosis (CWP)/Anthracosis. This disease is caused by the continuous inhalation of fine coal dust particles, which accumulate in the lungs and cannot be removed by the body. Over time, the lungs become blackened, thickened, and scarred, reducing their efficiency in supplying oxygen to the blood. Symptoms include chronic cough, breathing difficulty, chest pain, and in severe cases, respiratory failure.

Prevention: Long-term exposure to coal dust should be minimized. This can be achieved by improving ventilation in coal mines, using dust suppression techniques, and providing protective respiratory equipment to workers. Regular medical check-ups of miners are also essential to detect the disease at an early stage and prevent complications. 

4. What are some of the major pollutants from a thermal power plant? What can be done to minimize these?

Ans: Major Pollutants:

Thermal power plants release a variety of pollutants into the environment:

(i) Sulphur dioxide (SO₂) – causes acid rain and respiratory problems.

(ii) Carbon dioxide (CO₂) – contributes to global warming and climate change.

(iii) Carbon monoxide (CO) – toxic gas harmful to human health.

(iv) Oxides of nitrogen (NOₓ) – cause smog and respiratory diseases.

(v) Suspended particulate matter (SPM) – causes air pollution, lung problems, and reduces visibility.

(vi) Ozone (O₃) – formed secondarily, contributes to photochemical smog.

Steps to Minimize Pollution:

(i) Use of cleaner technologies – such as electrostatic precipitators, scrubbers, and filters to reduce dust and smoke.

(ii) Coal washing/refining before burning – reduces ash and sulphur content.

(iii) Shift to renewable energy – solar, wind, and hydropower as alternatives to coal.

(iv) Adoption of energy-efficient practices – conservation of electricity and promotion of cleaner fuels.

Gradual transition to nuclear and natural gas plants – as they produce fewer air pollutants.

5. Describe the symptoms of arsenic poisoning from drinking polluted ground water. In which parts of the body can arsenic accumulation be detected?

Ans: Arsenic intoxication:

(i) Melanosis: The appearance of black spots in the upper chest, back, and sides.

(ii) Keratosis: hands get hard, and patients can suffer from diarrhea, stomach pain, respiratory issues, etc.

Later along with dark spots, white spots appear, legs become swollen, and walking becomes uncomfortable and painful, some wounds tend to bleed, the liver and kidneys are damaged.

6. Discuss the problems caused in infants by high nitrate concentration in drinking water.

Ans: Babies develop Blue Baby Disease with an elevated density of nitrite in drinking water, Nitrite ions interact with haemoglobin to form methaemoglobin, which inhibits the oxygen-carrying ability of the blood, causing a type of anaemia known as methemoglobinemia. Signs include sleeping, inadequate eating, diminished energy, etc.

7. List auditory and non-auditory problems caused by too much noise.

Ans: Auditory effects:

(i) Auditory fatigue.

(ii) Deafness or impaired hearing.

Non-auditory effects:

(i) Interference with speech and communication.

(ii) Annoyance.

(iii) Efficiency.

(iv) The general change in the body.

8. Discuss the significance of addition of tetraethyl lead to petrol. Why has been the use of leaded petrol discontinued?

Ans: Tetraethyl lead (TEL) was added to petrol as an anti-knock agent to improve engine performance and ensure smooth running of vehicles. However, lead is a highly toxic heavy metal that causes chronic poisoning when released into the environment. It can contaminate air, water, and food, leading to its accumulation in the human body. Continuous exposure to lead causes neurological damage, behavioral disorders, learning disabilities, brain damage in children, kidney and lung cancers, and other serious health problems.

Due to these harmful effects, the use of leaded petrol has been discontinued worldwide and replaced with unleaded petrol or alternative anti-knock compounds. This phase-out was a major step to reduce air pollution and protect human health, especially in children.

9. How does a cancerous tumor differ from a non-carcinogenic tumor?

Ans: 

Cancerous Tumor	Non-cancerous Tumor
(i) Also known as Malignant tumors.	(i) Also known as Benign tumors.
(ii) It is harmful and cannot be removed surgically.	(ii) It is not harmful and can be removed surgically.
(iii) They enter bloodstream and lymphatic system and reach other parts of the body.	(iii) It remains confines to one place or part of the body.

10. What are some of the major effects of smoking and chewing tobacco?

Ans: Smoking and chewing tobacco have several harmful effects on human health. They can cause cancers of the mouth, throat, lungs, stomach, liver, colon, and rectum. Tobacco also damages the respiratory system, leading to chronic bronchitis, emphysema, and reduced lung function. Chewing tobacco and snuff increase the risk of oral cancers, gum disease, and tooth decay. In addition, smoking contributes to heart disease, high blood pressure, and stroke. Passive smoking (second-hand smoke) is equally dangerous, as non-smokers exposed to tobacco smoke are also at higher risk of cancer and respiratory illnesses.