Environmental Health — MCQs

Environmental Health Indian Medical PG Practice Questions and MCQs

Question 731: In rural areas, what is the recommended distance for cattle sheds to be placed away from houses?

A. 5 feet
B. 10 feet
C. 20 feet
D. 25 feet (Correct Answer)

Explanation: ***25 feet*** - A minimum distance of **25 feet (approximately 7.6 meters)** is recommended between cattle sheds and houses in rural areas. - This distance helps to mitigate **odors, flies, dust, and noise**, contributing to better hygiene and living conditions. *5 feet* - A distance of **5 feet** is generally considered too close and would not effectively prevent the transmission of **odors, pests, and potential pathogens** from cattle sheds to houses. - This proximity increases the risk of **nuisance and health hazards** to residents. *10 feet* - While better than 5 feet, a distance of **10 feet** may still be insufficient to adequately separate cattle sheds from houses to prevent issues like **strong odors and fly infestations**. - This proximity could still lead to **sanitation and comfort concerns** for residents. *20 feet* - A distance of **20 feet** offers a reasonable buffer; however, **25 feet** is the more commonly recommended minimum to ensure a greater margin of safety and comfort. - While 20 feet is better for ventilation and pest control than smaller distances, it might still allow some impact on **residential air quality**.

Question 732: What percentage of waste generated in hospitals is considered infectious?

A. 80% of waste is infectious
B. 100% of waste is infectious
C. 65% of waste is infectious
D. 15-20% of waste is infectious (Correct Answer)

Explanation: ***15-20% of waste is infectious*** - This is the **correct answer** as per WHO guidelines and standard biomedical waste management protocols. - Approximately **10-25% of hospital waste is classified as hazardous**, which includes infectious, pathological, sharps, chemical, pharmaceutical, and radioactive waste. - The remaining **75-90% is non-hazardous general waste** similar to domestic waste, including paper, packaging, food waste, and administrative materials. - Proper **waste segregation** is crucial to prevent mixing of infectious waste with general waste, which would unnecessarily increase handling and disposal costs. *65% of waste is infectious* - This is **incorrect** as it grossly overestimates the proportion of infectious waste. - Only a **minority of hospital waste is hazardous/infectious**, not the majority. - Such a high percentage would indicate poor waste segregation practices. *80% of waste is infectious* - This is **incorrect** and represents a severe overestimation. - The vast majority of hospital waste is actually **non-hazardous general waste**. - This misconception can lead to unnecessary treatment of general waste, increasing costs. *100% of waste is infectious* - This is **completely incorrect** and contradicts all biomedical waste management guidelines. - Hospitals generate significant amounts of **general administrative and domestic waste** that is not infectious. - Treating all waste as infectious would be economically unsustainable and environmentally unnecessary.

Question 733: In waste management, organic load is measured by which of the following?

A. Biological oxygen demand (Correct Answer)
B. Chemical oxygen demand
C. Suspended solid
D. Total dissolved solids

Explanation: ***Biological oxygen demand (BOD)*** - BOD is the **standard and primary measure of organic load** in waste management and wastewater treatment. - It measures the amount of **dissolved oxygen consumed by microorganisms** while decomposing biodegradable organic matter in water over a specific period (typically 5 days at 20°C - BOD₅). - Directly reflects the **biodegradable organic pollution** in wastewater and is the **gold standard** for assessing organic load in environmental health monitoring. - Used worldwide for **regulatory compliance** and treatment plant performance evaluation. *Chemical oxygen demand (COD)* - Measures the total quantity of oxygen required to **oxidize all organic AND inorganic compounds** in water chemically. - Gives **higher values than BOD** because it includes non-biodegradable substances and inorganic matter. - Useful as a **supplementary test** and provides faster results, but **does not specifically measure organic load alone**. - COD/BOD ratio helps assess biodegradability of wastewater. *Suspended solid* - Refers to particles suspended in water that **will not pass through a filter**. - Represents **physical impurities** rather than a direct measure of organic load. - Can carry organic material but is not a biochemical measure of organic pollution. *Total dissolved solids* - Measures all **inorganic and organic substances** dissolved in water. - Not a specific measure of organic load but rather overall water quality parameter.

Question 734: Which of the following is not a source of environmental radiation?

A. Uranium
B. Radon
C. CO (Correct Answer)
D. Radium

Explanation: ***CO*** - **Carbon monoxide (CO)** is a toxic gas produced by incomplete combustion, but it is **not radioactive** and thus not a source of environmental radiation. - Its danger comes from its ability to bind to **hemoglobin**, preventing oxygen transport, not from emitting radiation. *Radium* - **Radium** is a highly **radioactive element** found naturally in the environment as a decay product of uranium and thorium. - It emits **alpha and gamma radiation**, contributing significantly to natural background radiation. *Uranium* - **Uranium** is a naturally occurring **radioactive element** found in rocks, soil, and water. - It decays through a series of steps, emitting **alpha, beta, and gamma radiation**, and is a primary source of environmental background radiation. *Radon* - **Radon** is a **radioactive gas** that is formed from the decay of uranium in soil and rocks. - It is a significant source of **indoor environmental radiation exposure** and a known cause of lung cancer.

Question 735: What is considered the most critical component of the activated sludge process?

A. Primary sedimentation tank
B. Sludge digester
C. Aeration tank (Correct Answer)
D. Final settling tank

Explanation: ***Aeration tank*** - The **aeration tank** is where **microorganisms** are mixed with wastewater, supplied with oxygen, and allowed to break down organic pollutants. This biological process is central to the activated sludge method. - Without proper aeration and microbial activity in this tank, the **biological treatment** and pollutant removal would not occur effectively. *Primary sedimentation tank* - The **primary sedimentation tank** is involved in **pre-treatment**, removing settleable solids from raw wastewater before it enters the biological treatment. - While important for reducing the load on the activated sludge process, it does not perform the core **biological degradation** that defines the process. *Sludge digester* - The **sludge digester** processes the excess sludge generated from the activated sludge system to reduce its volume and stabilize it, often producing **biogas**. - It is a **post-treatment** component for sludge management, not directly involved in the primary biological treatment of wastewater. *Final settling tank* - The **final settling tank**, also known as a clarifier, separates the treated water from the **activated sludge microorganisms** after the aeration tank. - Its role is to clarify the effluent and return the active sludge to the aeration tank, making it crucial for solids separation but not for the actual **biological purification** itself.

Question 736: What is the best type of incinerator for the disposal of infectious waste?

A. Single-chamber incinerator
B. Triple-chamber incinerator
C. No incinerator
D. Double-chamber incinerator (Correct Answer)

Explanation: ***Double-chamber incinerator*** - A **double-chamber incinerator** is considered the most appropriate for infectious waste disposal as it allows for complete combustion. - The primary chamber burns the waste, and the secondary chamber burns the remaining gases and particulates, ensuring effective sterilization and minimizing harmful emissions. *Single-chamber incinerator* - **Single-chamber incinerators** are generally not recommended for infectious waste. - They often result in incomplete combustion, leading to the release of harmful emissions and potentially viable pathogens. *Triple-chamber incinerator* - While sometimes used, a **triple-chamber incinerator** is usually overkill and more complex than necessary for routine infectious waste. - The additional chamber significantly increases complexity and operating costs without substantial further benefits over a well-designed double-chamber system for this specific purpose. *No incinerator* - Disposing of infectious waste without an incinerator or other high-heat treatment method poses significant public health and environmental risks due to the potential spread of pathogens. - Other methods like autoclaving or chemical disinfection are used for specific types of infectious waste, but incineration remains a key method for overall disposal.

Question 737: Which agency monitors air quality in India?

A. None of the above
B. Central pollution control board (Correct Answer)
C. Central air quality board
D. Central public works dept

Explanation: ***Central pollution control board*** - The **Central Pollution Control Board (CPCB)** is responsible for setting standards and monitoring air quality across India. - It works under the **Ministry of Environment, Forest and Climate Change (MoEFCC)**. *Central air quality board* - There is **no specific agency** or board named "Central Air Quality Board" in India. - Air quality monitoring falls under the broader mandate of pollution control. *Central public works dept* - The **Central Public Works Department (CPWD)** is primarily involved in the construction and maintenance of government buildings and infrastructure. - It does **not have a mandate** for environmental monitoring like air quality. *None of the options* - This option is incorrect because the **Central Pollution Control Board** is the correct agency responsible for air quality monitoring. - There is a specific statutory organization fulfilling this role.

Question 738: In winter, water vapours and pollutants come to lie in the lowermost layer of atmosphere by -?

A. Acid rain
B. Greenhouse effect
C. Temperature inversion (Correct Answer)
D. None of the options

Explanation: ***Temperature inversion*** - **Temperature inversion** is an atmospheric phenomenon where a layer of cool air at the surface is trapped beneath a layer of warmer air. - This stable condition prevents the normal vertical mixing of air, causing pollutants and water vapors to accumulate in the lowest layer of the atmosphere, leading to conditions like **smog** and **fog**. *Acid rain* - **Acid rain** refers to precipitation (rain, snow, fog, etc.) that contains elevated levels of nitric and sulfuric acids. - It results from the emissions of sulfur dioxide and nitrogen oxides into the atmosphere, which then react with water, oxygen, and other chemicals, rather than directly causing pollutants to lie in the lowermost layer. *Greenhouse effect* - The **greenhouse effect** is a natural process where certain gases in Earth's atmosphere trap heat, warming the planet. - While it affects global temperatures, it does not directly explain the specific phenomenon of pollutants and water vapors being trapped in the lowermost atmospheric layer during winter due to atmospheric stability. *None of the options* - Since **temperature inversion** accurately describes the mechanism responsible for trapping pollutants and water vapors in the lowermost atmospheric layer, this option is incorrect.

Question 739: What is the common adulterant found in black pepper?

A. Khesari dal
B. Fine sand
C. None of the options
D. Dried papaya seeds (Correct Answer)

Explanation: ***Dried papaya seeds*** - **Dried papaya seeds** are a common adulterant in black pepper due to their similar size, shape, and color, making them difficult to distinguish visually. - Adulteration with papaya seeds is often done to increase the bulk and weight of the black pepper product, thereby reducing production costs. *Khesari dal* - **Khesari dal (Lathyrus sativus)** is a type of lentil known for causing **lathyrism**, a neurotoxic disorder, but it is not typically used to adulterate black pepper. - Its appearance and texture are distinctly different from black pepper, making it an unsuitable adulterant. *Fine sand* - **Fine sand** can be an adulterant in spices, but it is more commonly found in powdered spices like chilli powder or turmeric due to its fine particle size. - While it adds weight, its presence in whole black pepper would be easily detectable due to its abrasive texture and grittiness. *None of the options* - This option is incorrect because **dried papaya seeds** are a well-documented and common adulterant in black pepper. - The similarities in appearance make it a frequent choice for unscrupulous suppliers.

Question 740: Radiation exposure during infancy has been linked to which one of the following carcinoma?

A. Thyroid carcinoma (Correct Answer)
B. Breast carcinoma
C. Melanoma
D. Lung carcinoma

Explanation: ***Thyroid carcinoma*** - The **thyroid gland** is particularly susceptible to radiation-induced damage, especially during childhood and infancy due to its rapid growth and high cellular turnover. - **Iodine-131 exposure**, often from nuclear accidents, is a well-established cause of thyroid cancer in children. *Breast carcinoma* - While radiation exposure is a known risk factor for **breast cancer**, the risk is generally higher with exposure during adolescence and early adulthood, coinciding with breast development, rather than infancy itself. - Cumulative radiation dose over a longer period, such as during multiple medical imaging procedures, contributes more significantly to this risk. *Melanoma* - **Melanoma** is primarily associated with **ultraviolet (UV) radiation exposure** from sunlight, particularly intense, intermittent exposure leading to sunburns. - Ionizing radiation, like that used in medical imaging, is not a primary risk factor for melanoma. *Lung carcinoma* - **Lung carcinoma** is strongly linked to **smoking** and exposure to environmental toxins such as radon, asbestos, and certain industrial chemicals. - While high-dose therapeutic radiation to the chest can increase the risk, routine diagnostic radiation in infancy is not a significant risk factor for lung cancer later in life.

Practice by Chapter

Water Quality and Health

Practice Questions

Air Pollution and Health Effects

Practice Questions

Solid Waste Management

Practice Questions

Hazardous Waste Management

Practice Questions

Housing and Health

Practice Questions

Noise Pollution

Practice Questions

Radiation Health Effects

Practice Questions

Climate Change and Health

Practice Questions

Environmental Impact Assessment

Practice Questions

Disaster Management and Preparedness

Practice Questions

Vector Control

Practice Questions

Environmental Legislation

Practice Questions

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