Environmental Health Practice Questions

Q: As an index of thermal comfort, the 'Corrected Effective Temperature' is considered to be an improvement over 'Effective Temperature'. It deals with which of the following factors? I. Air velocity II. Humidity III. Mean radiant heat IV. Sweat rate Select the correct answer using the code given below :

I, II and III. ***I, II and III*** - The **"Corrected Effective Temperature"** (CET) improves upon the standard Effective Temperature (ET) by incorporating the **mean radiant heat (radiant temperature)**, along with **air temperature**, **humidity**, and **air velocity**. - Unlike **Effective Temperature** which considered air temperature, humidity, and air velocity, CET acknowledges the significant impact of **radiant heat** from surrounding surfaces on human thermal comfort, making it a more comprehensive index. - The key improvement: CET = ET + Mean Radiant Heat consideration. *I, III and IV* - While **air velocity** and **mean radiant heat** are indeed considered in CET, **sweat rate** is not a direct input parameter for calculating CET. - **Sweat rate** is a physiological response to thermal stress, not an environmental factor measured by thermal comfort indices. - CET aims to provide an objective index of thermal sensation based on environmental parameters, rather than individual physiological responses. *II, III and IV* - This option correctly identifies **humidity** and **mean radiant heat** as factors, but incorrectly includes **sweat rate** as a direct component of CET calculation. - **Air velocity** (I) is a crucial factor in both ET and CET, and its exclusion makes this option incomplete and incorrect. *I and II only* - This option is incomplete as it omits **mean radiant heat (III)**, which is the defining improvement that distinguishes CET from ET. - While **air velocity (I)** and **humidity (II)** are indeed part of CET, without including the radiant heat component, this would essentially describe only part of the Effective Temperature index, not the Corrected version.

Q: Water contamination with which chemical can lead to methaemoglobinaemia?

Nitrate. ***Nitrate*** - **Nitrate** compounds in contaminated water can be reduced to **nitrites** in the gastrointestinal tract, especially in infants. - **Nitrites** oxidize the iron in **hemoglobin** from the ferrous (Fe2+) to the ferric (Fe3+) state, forming **methaemoglobin**, which cannot bind oxygen. *Sulphide* - **Sulphide** (e.g., hydrogen sulfide) poisoning primarily affects the **respiratory and nervous systems** by inhibiting cytochrome c oxidase. - It does not directly cause the formation of **methaemoglobin** as its primary mechanism of toxicity. *Fluoride* - **Fluoride** contamination is primarily associated with **dental fluorosis** (mottling of teeth) and **skeletal fluorosis** (bone and joint pain, brittle bones). - It does not directly induce **methaemoglobinaemia** as its main toxicological effect. *Cyanide* - **Cyanide** poisoning acts by inhibiting **cytochrome c oxidase** in the mitochondrial electron transport chain, leading to cellular hypoxia. - While it can impair oxygen utilization, it does not primarily cause **methaemoglobinaemia** by oxidizing hemoglobin.

Q: The 'Nalgonda Technique' developed by the National Environmental Engineering Research Institute (NEERI) was developed primarily for the removal of which one of the following from water ?

Fluoride. ***Fluoride*** - The **Nalgonda Technique** is a defluoridation method primarily used to remove excess **fluoride** from drinking water. - This technique utilizes the principles of chemical precipitation, adsorption, and ion exchange, using **alum** (aluminum sulfate), **lime**, and **bleaching powder** as coagulants. - Developed by NEERI to address endemic **fluorosis** in areas with high fluoride content in groundwater, particularly in regions like Nalgonda district in Telangana. *Chlorine* - Chlorine is commonly used as a **disinfectant** in water treatment to kill bacteria and viruses, not as a target for removal by the Nalgonda Technique. - Excess chlorine can be removed via activated carbon filtration or aeration, methods distinct from the Nalgonda process. *Iron* - Iron removal from water typically involves **aeration**, oxidation (e.g., with chlorine or potassium permanganate), followed by filtration. - While alum (a component of the Nalgonda Technique) can aid in iron precipitation, the Nalgonda Technique's primary design is not for iron removal. *Asbestos* - Asbestos fibers are typically removed from water using **filtration methods** like membrane filtration or granular media filtration. - The Nalgonda Technique is a chemical precipitation process not specifically designed or effective for the removal of fibrous materials like asbestos.

Q: Which one among the following types of ventilation, best fits the following description - "A system of ventilation in which fresh air is blown into the room by centrifugal fans so as to create a positive pressure, and displace the vitiated air" ?

Plenum ventilation. ***Plenum ventilation*** - **Plenum ventilation** involves blowing fresh air into a space using fans, creating a **positive pressure** that displaces stale air. - This method is effective for maintaining good air quality and preventing the infiltration of unconditioned air from outside. *Exhaust ventilation* - **Exhaust ventilation** involves drawing air out of a space, creating a negative pressure, which allows fresh air to enter naturally. - This method is often used to remove contaminated air from specific areas, like kitchens or bathrooms, rather than supplying fresh air to an entire room. *Balanced ventilation* - **Balanced ventilation** systems aim to supply and exhaust equal amounts of air, maintaining neutral pressure within the space. - While it uses fans for both supply and exhaust, it doesn't primarily aim to create a positive pressure and displace air as described. *Natural ventilation* - **Natural ventilation** relies on natural forces like wind pressure and thermal buoyancy to move air through a building. - It does not involve mechanical fans to blow air, nor does it typically create a controlled positive pressure to displace vitiated air.

Q: Consider the following statements about working of septic tanks : 1. They are recommended for large communities, rather than small communities. 2. There should be no air space between the level of liquid in the tank and the undersurface of the cover. 3. Liquid effluent from the outlet pipe is free from all pathogens. How many of the statements given above are correct?

Only one of the statements. ***Only one of the statements*** - **This is correct.** Only statement 2 is accurate regarding septic tank operation. **Analysis of each statement:** **Statement 1 (Incorrect):** Septic tanks are recommended for **small communities and individual households**, NOT large communities. Large communities require centralized sewage treatment plants with higher capacity and more sophisticated treatment processes. Septic tanks are ideal for rural areas, scattered housing, and small institutions where centralized sewage systems are not feasible. **Statement 2 (Correct):** There should be **no air space** (or minimal air space) between the liquid level and the cover undersurface to maintain **anaerobic conditions** essential for septic tank functioning. The anaerobic bacteria that decompose organic matter require an oxygen-free environment. This design principle ensures proper digestion of sewage solids in the tank. **Statement 3 (Incorrect):** Liquid effluent from septic tanks is **NOT free from all pathogens**. The septic tank provides only primary treatment, removing settleable solids and partially digesting organic matter. The effluent still contains pathogenic bacteria, viruses, and parasites. This is why the effluent requires further treatment through soak pits, leach fields, or secondary treatment before safe disposal. *All the three statements* - Incorrect because statements 1 and 3 are false. *Only two of the statements* - Incorrect because only statement 2 is accurate. *None of the statements* - Incorrect because statement 2 about maintaining anaerobic conditions is correct.

Q: The method of combined disposal of refuse and night soil is known as

composting. ***Composting*** - Composting is a biological process where **organic matter**, including refuse and night soil, **decomposes** under controlled conditions to produce a **nutrient-rich humus**. - This method effectively **stabilizes waste**, reduces pathogens, and recycles valuable resources back into the environment. *Incineration* - Incineration involves the **combustion of waste at high temperatures** to reduce its volume and weight, often producing energy. - It is primarily used for **solid waste disposal** and is not typically combined with night soil due to the high moisture content and potential for air pollution. *Dumping* - Dumping refers to the **unregulated disposal of waste** in open areas, leading to environmental pollution and health hazards. - This method provides **no treatment** or control for refuse or night soil and is an unsanitary practice. *Controlled tipping* - Controlled tipping, or **sanitary landfilling**, involves depositing waste in a systematic manner, covering it with soil daily to minimize environmental impact. - While it's an improved waste disposal method, it doesn't involve the **biological breakdown and resource recovery associated with combining night soil with refuse**.

Q: Which types of cancer are associated with exposure to ionizing radiation? 1. Leukaemia 2. Lung cancer 3. Breast cancer 4. Lymphoma Select the correct answer using the code given below.

1, 2 and 3. ***1, 2 and 3*** - **Leukemia**, particularly acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL), is one of the most strongly established radiation-induced cancers, with clear dose-response relationships observed in atomic bomb survivors and therapeutic radiation patients. - **Lung cancer** risk increases significantly with ionizing radiation exposure, especially from inhaled radioactive particles (radon), uranium mining, and external radiation exposure in atomic bomb survivors. - **Breast cancer** has a well-documented association with ionizing radiation, particularly with exposure during childhood and adolescence. Evidence comes from atomic bomb survivors, tuberculosis fluoroscopy studies, and therapeutic chest radiation (e.g., for Hodgkin lymphoma). Women exposed to radiation before age 30 show the highest risk. *1, 2 and 4* - While leukemia and lung cancer are correctly included, this option incorrectly includes lymphoma instead of breast cancer. - **Lymphoma's** association with ionizing radiation is less consistent and weaker compared to breast cancer. The evidence for radiation-induced lymphoma is limited and not as well-established as for the three solid tumors and leukemia listed above. *1, 3 and 4* - This option correctly includes leukemia and breast cancer but incorrectly excludes lung cancer, which has strong epidemiological evidence from radon exposure studies and atomic bomb survivor data. - Lymphoma is included but has weaker evidence than lung cancer for radiation association. *2, 3 and 4* - This option incorrectly excludes leukemia, which is historically the most strongly documented and earliest-appearing cancer following radiation exposure. - Leukemia was the first cancer type conclusively linked to ionizing radiation in atomic bomb survivors.

Q: Consider the following measures for making unlined katcha wells sanitary: 1. Deepening the bottom 2. Filling the well with clay up to the water level and with coarse sand above that level 3. Installing a hand pump with screen 4. Constructing a platform and drainage once the material used for filling is completely consolidated Which of the above measures are effective in making unlined katcha wells sanitary?

1, 2, 3 and 4. ***1, 2, 3 and 4*** - All four measures are crucial for improving the **sanitary conditions** of unlined 'katcha' wells and preventing contamination. - These steps collectively address issues like surface water intrusion, subsurface filtration, and safe water extraction. *2 and 3 only* - This option is incomplete as it misses other vital steps like **deepening the bottom** to access cleaner water strata and **constructing a proper platform and drainage** to prevent surface contamination. - Focusing solely on filling and pump installation is insufficient for comprehensive well sanitation. *1 and 2 only* - This option overlooks the importance of installing a **hand pump with a screen** for hygienic water extraction and constructing a **platform with drainage** to prevent surface water runoff into the well. - Simply deepening and filling does not guarantee safe water delivery or protect against surface pollutants. *1, 3 and 4 only* - This option omits the critical step of **filling the well with clay and coarse sand**, which acts as a natural filter to remove impurities from the water as it seeps into the well. - Without proper filtration, deepening and surface protection alone may not ensure safe water quality.

Q: Throughout history, humans have been adapting environment to the genes more than adapting genes to the environment. Adapting environment to the genes is called

euthenics. ***Euthenics*** - **Euthenics** is the study of improving human functioning and well-being by improving **environmental conditions**. - This concept focuses on **adapting the environment** (e.g., nutrition, sanitation, housing) to suit existing human genetic predispositions. *Euphenics* - **Euphenics** involves improving human characteristics through the **alteration of the genes** or treating conditions that arise from genetic defects. - This field includes interventions like **gene therapy** or medical treatments to counteract genetic disorders. *Eugenics* - **Eugenics** is a set of beliefs and practices aiming to **improve the genetic quality** of the human population, typically by encouraging reproduction among those with "desirable" traits and discouraging it among those with "undesirable" traits. - Historically, it has been associated with **socially coercive policies** and is now largely discredited due to its unethical implications. *Acculturation* - **Acculturation** is the process of cultural and psychological change that results from contact between different cultures, leading to the **adoption of new cultural traits**. - It describes changes individuals or groups undergo when exposed to a new culture, not the direct manipulation of genes or environment for genetic improvement.

Question 1

As an index of thermal comfort, the 'Corrected Effective Temperature' is considered to be an improvement over 'Effective Temperature'. It deals with which of the following factors?
I. Air velocity
II. Humidity
III. Mean radiant heat
IV. Sweat rate

Select the correct answer using the code given below :

Accepted Answer

I, II and III

Answer

I, III and IV

Answer

II, III and IV

Answer

I and II only

Question 2

Water contamination with which chemical can lead to methaemoglobinaemia?

Accepted Answer

Nitrate

Answer

Sulphide

Answer

Fluoride

Answer

Cyanide

Question 3

The 'Nalgonda Technique' developed by the National Environmental Engineering Research Institute (NEERI) was developed primarily for the removal of which one of the following from water ?

Accepted Answer

Fluoride

Answer

Chlorine

Answer

Iron

Answer

Asbestos

Question 4

Which one among the following types of ventilation, best fits the following description - "A system of ventilation in which fresh air is blown into the room by centrifugal fans so as to create a positive pressure, and displace the vitiated air" ?

Accepted Answer

Plenum ventilation

Answer

Exhaust ventilation

Answer

Balanced ventilation

Answer

Natural ventilation

Question 5

Consider the following statements about working of septic tanks :

1. They are recommended for large communities, rather than small communities.
2. There should be no air space between the level of liquid in the tank and the undersurface of the cover.
3. Liquid effluent from the outlet pipe is free from all pathogens. How many of the statements given above are correct?

Accepted Answer

Only one of the statements

Answer

All the three statements

Answer

Only two of the statements

Answer

None of the statements

Question 6

The method of combined disposal of refuse and night soil is known as

Accepted Answer

composting

Answer

incineration

Answer

dumping

Answer

controlled tipping

Question 7

Which types of cancer are associated with exposure to ionizing radiation?

1. Leukaemia
2. Lung cancer
3. Breast cancer
4. Lymphoma

Select the correct answer using the code given below.

Accepted Answer

1, 2 and 3

Answer

1, 2 and 4

Answer

1, 3 and 4

Answer

2, 3 and 4

Question 8

In which way is 'membrane filtration technique' better than 'multiple tube method' for determining the presence of coliform organisms in water?

Accepted Answer

Membrane filtration technique is much quicker and results can be obtained within 20 hours, while multiple tube method is much longer.

Answer

Membrane filtration technique is more universally available, and hence, easily doable.

Answer

Membrane filtration technique can only be carried out by trained hands.

Answer

Membrane filtration technique is far cheaper than multiple tube method.

Question 9

Consider the following measures for making unlined katcha wells sanitary:

1. Deepening the bottom
2. Filling the well with clay up to the water level and with coarse sand above that level
3. Installing a hand pump with screen
4. Constructing a platform and drainage once the material used for filling is completely consolidated

Which of the above measures are effective in making unlined katcha wells sanitary?

Accepted Answer

1, 2, 3 and 4

Answer

2 and 3 only

Answer

1 and 2 only

Answer

1, 3 and 4 only

Question 10

Throughout history, humans have been adapting environment to the genes more than adapting genes to the environment. Adapting environment to the genes is called

Accepted Answer

euthenics

Answer

euphenics

Answer

eugenics

Answer

acculturation

Environmental Health — MCQs

Environmental Health — MCQs

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