Environmental Health Practice Questions

Q: 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?

1, 2 and 4. ***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.

Q: In swimming pools, the free residual chlorine required for providing adequate protection against bacterial and viral agents should be

1.0 mg/litre. ***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.

Q: The following are all residual insecticides except

Pyrethrum. ***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.

Q: Kata thermometer is used for recording :

Low air velocities. ***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.

Q: During the process of chlorination of water, the disinfecting action of chlorine is due to the formation of

Hypochlorous acid and hypochlorite ions. ***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.

Q: Horrock's apparatus is used to measure :

Free chlorine. ***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.

Q: The method of choice for purification of highly polluted water on a large scale is :

Super-chlorination followed by de-chlorination. ***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.

Q: Discarded tablets are disposed of in :

Yellow plastic bag. ***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.

Q: Consider the following : 1. Magnesium Sulphate 2. Calcium bicarbonate 3. Calcium Sulphate 4. Magnesium bicarbonate Hardness of water relates to the presence of which of the above?

1, 2, 3 and 4. **Correct Answer: 1, 2, 3 and 4** **Hardness of water** is caused by the presence of dissolved multivalent metallic cations, primarily **calcium (Ca²⁺)** and **magnesium (Mg²⁺)** ions. These ions combine with various anions to form compounds that cause water hardness: - **Magnesium sulfate (MgSO₄)** - Causes **permanent hardness** (cannot be removed by boiling) - **Calcium bicarbonate (Ca(HCO₃)₂)** - Causes **temporary hardness** (can be removed by boiling) - **Calcium sulfate (CaSO₄)** - Causes **permanent hardness** - **Magnesium bicarbonate (Mg(HCO₃)₂)** - Causes **temporary hardness** **Therefore, all four compounds (1, 2, 3, and 4) contribute to water hardness.** *Why other options are incorrect:* *1, 2 and 3 only* - Incorrectly excludes **magnesium bicarbonate**, which is a significant contributor to temporary hardness *2, 3 and 4 only* - Incorrectly excludes **magnesium sulfate**, which contributes to permanent hardness *1 and 4 only* - Incorrectly omits **calcium bicarbonate** and **calcium sulfate**, which are major contributors to both temporary and permanent hardness

Q: Which of the following insecticides is a natural contact poison?

Rotenone. ***Rotenone*** - **Rotenone** is a naturally occurring plant-derived insecticide, traditionally used as a **contact poison** and **stomach poison**. - It is effective against a broad spectrum of insects and works by inhibiting **electron transport** in the mitochondria, disrupting cellular respiration. *Propoxur* - **Propoxur** is a **synthetic carbamate insecticide**, not a natural one. - It acts primarily as a **cholinesterase inhibitor**, interfering with nervous system function. *Carbaryl* - **Carbaryl** is a **synthetic carbamate insecticide**, derived from carbamic acid, not a natural product. - Its mechanism of action involves **reversible inhibition of acetylcholinesterase**, leading to nerve overstimulation. *Lindane* - **Lindane** is an **organochlorine insecticide**, which is a synthetic compound, not naturally occurring. - It acts as a **neurotoxin**, primarily by interfering with **GABA-gated chloride channels** in the insect's nervous system.

Question 1

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?

Accepted Answer

1, 2 and 4

Answer

2, 3 and 4

Answer

1, 3 and 4

Answer

1, 2 and 3

Question 2

In swimming pools, the free residual chlorine required for providing adequate protection against bacterial and viral agents should be

Accepted Answer

1.0 mg/litre

Answer

1.5 mg/litre

Answer

0.5 mg/litre

Answer

2.0 mg/litre

Question 3

The following are all residual insecticides except

Accepted Answer

Pyrethrum

Answer

Gamma BHC

Answer

Malathion

Answer

DDT

Question 4

Kata thermometer is used for recording :

Accepted Answer

Low air velocities

Answer

Relative humidity of the air

Answer

Mean radiant temperature

Answer

Maximum and minimum temperature

Question 5

During the process of chlorination of water, the disinfecting action of chlorine is due to the formation of

Accepted Answer

Hypochlorous acid and hypochlorite ions

Answer

Chlorine gas only

Answer

Hydrochloric acid only

Answer

Hypochlorous acid only

Question 6

Horrock's apparatus is used to measure :

Accepted Answer

Free chlorine

Answer

Free and combined chlorine

Answer

Chlorine demand

Answer

Combined chlorine

Question 7

The method of choice for purification of highly polluted water on a large scale is :

Accepted Answer

Super-chlorination followed by de-chlorination

Answer

Chlorination only

Answer

Ultraviolet light treatment

Answer

Boiling and chlorination

Question 8

Discarded tablets are disposed of in :

Accepted Answer

Yellow plastic bag

Answer

Black plastic bag

Answer

Red plastic bag

Answer

Blue plastic bag

Question 9

Consider the following :

1. Magnesium Sulphate
2. Calcium bicarbonate
3. Calcium Sulphate
4. Magnesium bicarbonate

Hardness of water relates to the presence of which of the above?

Accepted Answer

1, 2, 3 and 4

Answer

1, 2 and 3 only

Answer

2, 3 and 4 only

Answer

1 and 4 only

Question 10

Which of the following insecticides is a natural contact poison?

Accepted Answer

Rotenone

Answer

Propoxur

Answer

Carbaryl

Answer

Lindane

Environmental Health — MCQs

Environmental Health — MCQs

On this page

Practice by Chapter

Want unlimited practice?