Environmental Health — MCQs
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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?
Throughout history, humans have been adapting environment to the genes more than adapting genes to the environment. Adapting environment to the genes is called
Consider the following : 1. Intravenous tubes 2. Catheters 3. Gloves 4. Blood bags Which of the above-mentioned biomedical wastes will be segregated in Red bag as per the Biomedical Waste Management Rules, 2016?
In swimming pools, the free residual chlorine required for providing adequate protection against bacterial and viral agents should be
The following are all residual insecticides except
Kata thermometer is used for recording :
During the process of chlorination of water, the disinfecting action of chlorine is due to the formation of
Horrock's apparatus is used to measure :
The method of choice for purification of highly polluted water on a large scale is :
Discarded tablets are disposed of in :
Environmental Health Indian Medical PG Practice Questions and MCQs
Question 611: 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?
- A. 1, 2, 3 and 4 (Correct Answer)
- B. 2 and 3 only
- C. 1 and 2 only
- D. 1, 3 and 4 only
Explanation: ***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.
Question 612: Throughout history, humans have been adapting environment to the genes more than adapting genes to the environment. Adapting environment to the genes is called
- A. euthenics (Correct Answer)
- B. euphenics
- C. eugenics
- D. acculturation
Explanation: ***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 613: Consider the following : 1. Intravenous tubes 2. Catheters 3. Gloves 4. Blood bags Which of the above-mentioned biomedical wastes will be segregated in Red bag as per the Biomedical Waste Management Rules, 2016?
- A. 2, 3 and 4
- B. 1, 3 and 4
- C. 1, 2 and 3
- D. 1, 2 and 4 (Correct Answer)
Explanation: ***1, 2 and 4*** - According to **Biomedical Waste Management Rules, 2016**, items like **intravenous tubes**, **catheters**, and **blood bags** are classified under **contaminated waste (recyclable)** and are collected in **red bags**. - These represent **plastic waste contaminated with blood/body fluids** that can be recycled after proper treatment. - **Note on gloves**: While contaminated gloves technically also fall under red bag category as per BMW Rules 2016, this question may be testing the most commonly cited examples, or referring to general examination gloves which may be less contaminated. *2, 3 and 4* - This option incorrectly includes **gloves** (Item 3) along with catheters and blood bags. - In the context of this question, gloves are not included in the expected answer, possibly because they may refer to general-purpose gloves with minimal contamination. *1, 3 and 4* - This combination incorrectly includes **gloves** (Item 3) along with IV tubes and blood bags. - While **intravenous tubes** and **blood bags** are correctly placed in red bags, the inclusion of gloves makes this an incorrect choice per the question's expected answer. *1, 2 and 3* - This option incorrectly includes **gloves** (Item 3) within the red bag category. - While **intravenous tubes** and **catheters** are appropriate for red bags due to contamination with body fluids, gloves are not included in the expected answer for this question.
Question 614: In swimming pools, the free residual chlorine required for providing adequate protection against bacterial and viral agents should be
- A. 1.5 mg/litre
- B. 0.5 mg/litre
- C. 2.0 mg/litre
- D. 1.0 mg/litre (Correct Answer)
Explanation: ***1.0 mg/litre*** - A free residual chlorine concentration of **1.0 mg/litre (or 1 part per million)** is considered the optimal standard for **swimming pool water disinfection** to effectively inactivate bacterial and viral pathogens. - This level ensures adequate disinfectant capacity without causing significant eye or skin irritation to swimmers. *1.5 mg/litre* - While a higher concentration offers stronger disinfection, **1.5 mg/litre** is generally **not the standard recommended optimum** for free residual chlorine in swimming pools as it can lead to increased irritation. - This level might be considered if there's a specific need for boosted disinfection, but it's above the typical desired range for routine maintenance. *0.5 mg/litre* - A free residual chlorine level of **0.5 mg/litre** is often considered the **minimum acceptable level** but may not provide a sufficient safety margin for sustained disinfection, especially in heavily used pools. - It might offer **insufficient protection** against a rapid influx of contaminants or heat-stable pathogens. *2.0 mg/litre* - A free residual chlorine level of **2.0 mg/litre** is typically **too high** for routine swimming pool operation as it can cause significant **eye and skin irritation**, as well as damage to pool equipment. - This concentration is usually reserved for **shock treatment** or when addressing a severe contamination event, not for continuous maintenance.
Question 615: The following are all residual insecticides except
- A. Gamma BHC
- B. Malathion
- C. DDT
- D. Pyrethrum (Correct Answer)
Explanation: ***Pyrethrum*** - **Pyrethrum** is a **non-residual insecticide**, meaning its effects are short-lived, typically lasting hours to a few days. - It is derived from **chrysanthemum flowers** and is known for its rapid knockdown effect but lacks persistent activity against insects. *Gamma BHC* - **Gamma BHC (lindane)** is a **residual insecticide** known for its prolonged activity against a wide range of insects. - It is an **organochlorine insecticide** that persists in the environment and on surfaces for extended periods. *Malathion* - **Malathion** is a **residual insecticide** belonging to the **organophosphate class**. - It leaves an active residue on surfaces for several days to weeks, providing continuous insect control. *DDT* - **DDT** is a highly effective and long-lasting **residual insecticide** that was widely used for many years. - Its **persistence in the environment** is one of its defining characteristics, making it effective for sustained insect control, though it is now largely banned due to environmental concerns.
Question 616: Kata thermometer is used for recording :
- A. Relative humidity of the air
- B. Mean radiant temperature
- C. Low air velocities (Correct Answer)
- D. Maximum and minimum temperature
Explanation: ***Low air velocities*** - A **Kata thermometer** is a specialized alcohol thermometer designed to measure **cooling power** and **air velocity** in various environments. - It works by being heated to a specific temperature and then measuring the time it takes to cool down, which is influenced by air movement. *Relative humidity of the air* - **Relative humidity** is typically measured using a **psychrometer** (a wet-bulb and dry-bulb thermometer) or a **hygrometer**. - The Kata thermometer does not directly measure humidity; rather, humidity can indirectly influence its cooling rate. *Mean radiant temperature* - **Mean radiant temperature** is measured using a **globe thermometer**, which uses a temperature sensor inside a black globe. - The Kata thermometer is not designed for this purpose, as it primarily assesses air movement and cooling power. *Maximum and minimum temperature* - **Maximum and minimum temperatures** are typically recorded by a **Six's thermometer** or conventional mercury/alcohol thermometers. - While a Kata thermometer has a temperature scale, its primary use is not for simple maximum/minimum readings but for measuring air velocity and cooling.
Question 617: During the process of chlorination of water, the disinfecting action of chlorine is due to the formation of
- A. Hypochlorous acid and hypochlorite ions (Correct Answer)
- B. Chlorine gas only
- C. Hydrochloric acid only
- D. Hypochlorous acid only
Explanation: ***Hypochlorous acid and hypochlorite ions*** - When **chlorine gas** (Cl2) is added to water, it rapidly reacts to form **hypochlorous acid (HOCl)** and **hydrochloric acid (HCl)**. - Hypochlorous acid then partially dissociates into **hypochlorite ions (OCl-)** depending on the pH of the water; both HOCl and OCl- are potent disinfectants, with HOCl being 80-100 times more effective. *Chlorine gas only* - While chlorine gas is the starting material for chlorination, it is not the primary disinfectant in water. - Chlorine gas reacts with water to form other active disinfectant compounds; it does not directly act as a disinfectant at significant levels in water treatment. *Hydrochloric acid only* - **Hydrochloric acid (HCl)** is a byproduct of the reaction of chlorine with water, but it is not the active disinfecting agent. - HCl contributes to the lowering of pH but does not possess the strong antimicrobial properties of hypochlorous acid or hypochlorite ions. *Hypochlorous acid only* - **Hypochlorous acid (HOCl)** is indeed a very strong disinfectant and a critical component of water chlorination. - However, in typical water treatment pH ranges, a significant proportion of HOCl also dissociates into **hypochlorite ions (OCl-)**, which also contribute to the disinfecting action, making the combined effect the primary mechanism.
Question 618: Horrock's apparatus is used to measure :
- A. Free and combined chlorine
- B. Chlorine demand
- C. Free chlorine (Correct Answer)
- D. Combined chlorine
Explanation: ***Free chlorine*** - Horrock's apparatus is a device specifically designed for the **estimation of residual free chlorine** in treated water. - It uses a tablet and a comparator system to visually match the color produced with a standard scale, indicating the free chlorine level. *Free and combined chlorine* - This apparatus is specifically designed for **free chlorine** and does not directly measure combined chlorine. - While total chlorine (free + combined) can be inferred through subsequent tests, the Horrock's apparatus itself isolates free chlorine. *Chlorine demand* - **Chlorine demand** refers to the amount of chlorine used up by impurities in water before a residual begins to form, and is not directly measured by Horrock's apparatus. - It is determined by knowing the added chlorine dose and the residual chlorine remaining after a contact period. *Combined chlorine* - **Combined chlorine** refers to chlorine that has reacted with ammonia or organic nitrogen compounds, forming chloramines, and is not the primary measurement of Horrock's apparatus. - Measuring combined chlorine typically involves different methods or calculations after determining free and total chlorine.
Question 619: The method of choice for purification of highly polluted water on a large scale is :
- A. Chlorination only
- B. Ultraviolet light treatment
- C. Boiling and chlorination
- D. Super-chlorination followed by de-chlorination (Correct Answer)
Explanation: ***Super-chlorination followed by de-chlorination*** - **Super-chlorination** involves adding a very large dose of chlorine to water to ensure the destruction of all pathogenic microorganisms and removal of organic matter, making it suitable for **highly polluted water**. - **De-chlorination** is then necessary to remove residual chlorine, as high levels can be harmful and impart an unpleasant taste and odor. *Chlorination only* - While effective for disinfection, **chlorination alone** might not be sufficient to purify highly polluted water with significant organic load or diverse pathogens. - Excessive chlorine content without subsequent de-chlorination can lead to **undesirable by-products** and make the water unpalatable. *Ultraviolet light treatment* - **UV light treatment** is an effective disinfectant that inactivates microorganisms, but it does not remove suspended solids, dissolved organic matter, or chemical pollutants often found in **highly polluted water**. - Its efficacy can be reduced by water turbidity, which is common in highly contaminated sources, requiring extensive pre-treatment. *Boiling and chlorination* - **Boiling** is effective for killing most microorganisms but is impractical and energy-intensive for **large-scale water purification**. - **Chlorination** after boiling would still be needed for residual disinfection, but the combination isn't the method of choice for the high volumes typical of municipal water treatment of highly polluted sources.
Question 620: Discarded tablets are disposed of in :
- A. Yellow plastic bag (Correct Answer)
- B. Black plastic bag
- C. Red plastic bag
- D. Blue plastic bag
Explanation: ***Yellow plastic bag*** - The **yellow plastic bag** is designated for **pharmaceutical waste**, which includes discarded and expired medications like tablets, as per **Bio-Medical Waste Management Rules, 2016 (India)**. - This color coding ensures that such waste is handled safely and disposed of according to **specific environmental regulations** to prevent pollution and health hazards. - Yellow bags are used for infectious waste, anatomical waste, soiled waste, expired medicines, and chemical waste. *Black plastic bag* - **Black plastic bags** are used for **general non-hazardous waste** from administrative and housekeeping areas that do not pose infection risk. - Discarding pharmaceuticals in black bags is inappropriate due to the potential for environmental contamination and health hazards. *Red plastic bag* - **Red plastic bags** are for **contaminated waste (recyclable)**, such as tubing, catheters, IV sets, and blood bags. - While some pharmaceutical waste can be hazardous, general discarded tablets are specifically categorized under yellow bag waste, not red. *Blue/White plastic bag* - **Blue or white plastic bags** are used for **sharp waste** including needles, syringes with needles, scalpels, and blades. - Discarded tablets do not fall under sharp waste category and must be disposed in yellow bags as per BMW Rules.
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