Environmental Health — MCQs

Environmental Health Indian Medical PG Practice Questions and MCQs

Question 711: Cytotoxic and expired drug disposal is done by which method?

A. Dumping
B. Autoclave
C. Landfill
D. Burning (Correct Answer)

Explanation: ***Burning*** - **Incineration** (burning) at high temperatures is the most effective and safest method for disposing of cytotoxic and expired drugs. - This process ensures the complete destruction of **active pharmaceutical ingredients** and renders them harmless. - **High-temperature incineration** (>1200°C) is recommended for cytotoxic waste as per Biomedical Waste Management Rules. *Dumping* - **Dumping** drugs indiscriminately into the environment can lead to significant **environmental pollution**, contaminating water and soil. - This method poses serious risks to both **human health** and **wildlife** due to potential exposure to toxic substances. *Autoclave* - An **autoclave** uses **steam sterilization** under high pressure and temperature, primarily for sterilizing medical waste and equipment. - It is generally **ineffective** for the complete destruction of chemical compounds in cytotoxic and expired drugs. - Autoclaving is suitable for infectious waste, not chemical/pharmaceutical waste. *Landfill* - Disposing of cytotoxic and expired drugs in a **landfill** can lead to **leaching** of harmful chemicals into the groundwater and soil. - This method is environmentally unsound as it can result in **long-term contamination** and exposure risks.

Question 712: Which of the following does not cause hardness of water?

A. Calcium bicarbonate
B. Magnesium bicarbonate
C. Calcium carbonate (Correct Answer)
D. Calcium sulphate

Explanation: ***Calcium carbonate*** - Calcium carbonate (CaCO₃) in its **pure solid form has very low solubility** in water (~15 mg/L), making it the least likely of these compounds to directly contribute to water hardness. - While CaCO₃ can react with dissolved CO₂ to form soluble calcium bicarbonate, **pure calcium carbonate itself tends to precipitate out** as scale or sediment rather than remaining dissolved as ions that cause hardness. - This makes it the correct answer as the compound that **does not directly cause hardness** among the options listed. *Calcium bicarbonate* - **Calcium bicarbonate [Ca(HCO₃)₂] is highly soluble** in water and readily dissociates into Ca²⁺ and HCO₃⁻ ions. - This dissolved compound is a **primary cause of temporary hardness** in water, which can be removed by boiling. *Magnesium bicarbonate* - Similar to calcium bicarbonate, **magnesium bicarbonate [Mg(HCO₃)₂] is soluble** in water. - Its presence as dissolved Mg²⁺ ions contributes significantly to **temporary hardness**. *Calcium sulphate* - **Calcium sulphate (CaSO₄) is moderately soluble** in water. - It is a common cause of **permanent hardness** in water, as it cannot be removed by boiling and remains dissolved.

Question 713: Which of the following is not typically incinerated?

A. Animal waste
B. Broken thermometers (Correct Answer)
C. Infected solid waste
D. Human anatomical waste

Explanation: ***Broken thermometers*** - **Broken thermometers** often contain **mercury**, which, when incinerated, releases **toxic mercury vapor** into the atmosphere. - This poses a severe environmental and health hazard, requiring them to be handled as **hazardous waste** and recycled or disposed of in specialized facilities to prevent mercury release. *Human anatomical waste* - **Human anatomical waste**, including body parts, tissues, and recognizable organs, is highly infectious and poses significant biohazard risks. - **Incineration** is the preferred method for its disposal to ensure complete destruction of pathogens and reduce environmental contamination. *Animal waste* - **Animal waste** from research or healthcare settings (e.g., infected animal carcasses, bedding with animal excreta) is considered **biohazardous**. - **Incineration** effectively neutralizes pathogens and reduces the volume of such waste, preventing disease transmission. *Infected solid waste* - **Infected solid waste**, such as bandages, swabs, and disposable medical devices contaminated with blood or bodily fluids, carries a high risk of spreading infectious diseases. - **Incineration** at high temperatures ensures sterilization and safe disposal of these materials, destroying pathogenic microorganisms.

Question 714: In water testing from a well using Horrock's apparatus, blue color appears from the 4th cup onwards. What is the amount of bleaching powder required to disinfect 75000 litres of water?

A. 1600 gm
B. 2000 gm
C. 1300 gm
D. 100 gm (Correct Answer)

Explanation: ***100 gm*** - In **Horrock's apparatus** test, blue color appearing from the 4th cup indicates a **chlorine demand of 0.4 ppm (0.4 mg/L)** for the water sample. - **Total chlorine required** = 0.4 mg/L × 75,000 L = **30,000 mg = 30 gm** of pure chlorine. - Standard bleaching powder contains **30% available chlorine**, so: **Bleaching powder needed = 30 gm ÷ 0.30 = 100 gm**. - This is the scientifically accurate amount for disinfecting 75,000 liters of water with 0.4 ppm chlorine demand. *1000 gm* - This represents a **10-fold excess** over the actual requirement of 100 gm based on the measured chlorine demand. - Using 1000 gm would result in severe **over-chlorination** (4 ppm instead of 0.4 ppm), causing strong unpleasant taste, odor, and potential health concerns. *1600 gm* - This amount represents **16 times the required dose**, leading to dangerously high chlorine levels in the water. - Such excessive chlorination would make the water unpalatable and potentially toxic to consumers. *2000 gm* - This represents a **20-fold excess**, providing extreme and harmful over-disinfection. - Such excessive amounts could lead to **chlorine toxicity** and would be wasteful and harmful to consumers. *1300 gm* - This amount exceeds the calculated requirement by **13 times**, providing unnecessary and harmful over-disinfection. - The precise calculation based on **0.4 ppm chlorine demand** and **75,000 L volume** yields exactly **100 gm**, not 1300 gm.

Question 715: At what fluoride concentration in drinking water does skeletal fluorosis typically occur?

A. < 1.5 mg/L
B. 1.5-3 mg/L
C. 3-6 mg/L (Correct Answer)
D. > 10 mg/L

Explanation: ***3-6 mg/L*** - Chronic exposure to drinking water with **fluoride concentrations of 3-6 mg/L** represents the **threshold range** where **early skeletal fluorosis** begins to manifest. - At concentrations **≥4 mg/L**, fluoride accumulation in bones exceeds the body's excretory capacity, leading to **increased bone density, osteosclerosis**, and early symptoms like **joint stiffness and bone pain**. - This range captures the **onset of skeletal manifestations**, though more severe changes occur at higher concentrations. *< 1.5 mg/L* - This range is **optimal for preventing dental caries** without causing adverse effects. - Fluoride concentrations below 1.5 mg/L are **safe** and do not cause skeletal or dental fluorosis. - Many water fluoridation programs target **0.5-1.0 mg/L** for dental health benefits. *1.5-3 mg/L* - This range primarily causes **dental fluorosis** (enamel mottling and discoloration) with chronic exposure, especially during tooth development. - **Skeletal fluorosis does not typically occur** at these concentrations, as the threshold for bone involvement is higher. - This is considered the range for cosmetic concerns rather than systemic skeletal disease. *> 10 mg/L* - Concentrations exceeding 10 mg/L lead to **severe, crippling skeletal fluorosis** with marked bone deformities, ligament calcification, and potential neurological complications. - This represents **advanced disease** rather than the typical onset of skeletal fluorosis. - Such high concentrations are found in endemic fluorosis regions with contaminated groundwater.

Question 716: Waste Sharps should be disposed in ?

A. Black bag
B. Yellow bag (Correct Answer)
C. None of the options
D. Blue bag

Explanation: ***Yellow bag (Historical answer per BMW Rules 1998)*** - Under the **Biomedical Waste Management Rules 1998** (applicable at the time of NEET-PG 2015), **sharps waste** including needles, syringes, and scalpels were disposed in **yellow puncture-proof containers**. - This was the correct answer when this question was asked in the 2015 examination. - **Current Guidelines (BMW Rules 2016):** Sharps are now disposed in **white/translucent puncture-proof containers**, NOT yellow bags. Yellow bags are currently used for soiled infectious waste like dressings and body fluid-contaminated materials. *Black bag* - **Black bags** are used for **general non-hazardous waste** that poses no biological risk. - Disposing of sharps in black bags creates serious **risk of needlestick injuries** and potential transmission of bloodborne pathogens. *None of the options* - This is incorrect because there is a specific, regulated method for disposing of sharps in healthcare settings. - Proper waste segregation is **mandatory** for safety and regulatory compliance. *Blue bag* - **Blue bags** (per BMW Rules 2016) are used for disposal of **glassware** (broken or discarded) and **metallic body implants**. - Under older guidelines, blue bags were for certain pharmaceutical waste. - They are not designated for sharps disposal.

Question 717: Horrock's apparatus is used to measure?

A. Wind velocity
B. Humidity
C. Chlorine demand (Correct Answer)
D. Cooling power

Explanation: ***Chlorine demand*** - Horrock's apparatus is specifically designed for determining the **chlorine demand** of water, which is the amount of **chlorine** consumed by impurities before a **free chlorine residual** is established. - This apparatus is crucial in **water treatment processes** to ensure effective **disinfection** by adjusting chlorine dosages. *Wind velocity* - **Wind velocity** is typically measured using an **anemometer**, a device with rotating cups or a propeller that spins in response to wind. - Horrock's apparatus has no components or mechanisms for detecting or quantifying wind movement. *Humidity* - **Humidity** is measured by instruments such as **hygrometers** or **psychrometers**, which assess the amount of water vapor in the air. - These devices utilize properties like **condensation** or changes in **electrical resistance**, which are unrelated to the function of Horrock's apparatus. *Cooling power* - **Cooling power** refers to the rate at which heat can be removed from a system and is measured using devices like **catathermometers** or specialized **calorimeters**. - Horrock's apparatus is a **chemical testing device** and does not have the capability to measure thermal properties or cooling rates.

Question 718: Anemometer measures?

A. Humidity
B. Air velocity (Correct Answer)
C. Room temperature
D. Radiant temperature

Explanation: ***Air velocity*** - An **anemometer** is a device specifically designed to measure **wind speed** or the **velocity of air currents**. - It is commonly used in **meteorology**, HVAC (Heating, Ventilation, and Air Conditioning) systems, and aerodynamic research. *Humidity* - **Humidity** is measured by a **hygrometer**, which quantifies the amount of water vapor in the air. - An anemometer does not have the capability to measure atmospheric moisture content. *Room temperature* - **Room temperature** is measured by a **thermometer**, which detects the thermal energy of the air. - While air velocity can influence perceived temperature, the anemometer directly measures movement, not heat. *Radiant temperature* - **Radiant temperature** is measured by a **radiometer** or an **infrared thermometer**, which assesses the heat emitted by surfaces. - This is distinct from air movement and requires different sensor technology.

Question 719: Which of the following statements about Culex larvae is correct?

A. Rest parallel to surface water
B. Long Palmate hair
C. Siphon tube present (Correct Answer)
D. All are false

Explanation: ***Siphon tube present*** - **Culex larvae** possess a prominent **siphon tube** at their posterior end, which is used for breathing by extending to the water surface. - This **siphon tube** is a key morphological feature that helps distinguish them from *Anopheles* larvae. *Rest parallel to surface water* - **Anopheles larvae** typically rest parallel to the water surface because they lack a long siphon and obtain oxygen directly through spiracles on their dorsal surface. - **Culex larvae**, due to their siphon tube, hang head-down at an angle from the water surface. *Long Palmate hair* - **Palmate hairs** are characteristic structures found on the abdomen of **Anopheles larvae** that help them float horizontally at the water surface. - **Culex larvae** do not possess well-developed palmate hairs. *All are false* - This statement is incorrect because the presence of a **siphon tube** is a defining characteristic of **Culex larvae**.

Question 720: Swajaldhara programme is associated with:

A. Provision of safe drinking water (Correct Answer)
B. Provision of food supplements for destitute women
C. Provision of relief for victim of sexual abuse
D. Provision of health care for sick tribals

Explanation: ***Provision of safe drinking water*** - The **Swajaldhara programme** was launched by the Government of India in 2002 to accelerate coverage of **drinking water supply** in rural areas - Its primary objective was to ensure access to **safe and sustainable drinking water sources** through community participation and decentralized management - The program emphasized local ownership with communities contributing 10% of project costs *Provision of food supplements for destitute women* - Food security programs for women fall under separate social welfare schemes like ICDS and PDS - The **Swajaldhara programme** was specifically focused on **water supply infrastructure**, not nutrition *Provision of relief for victim of sexual abuse* - Relief for victims of sexual abuse is addressed through **justice and women's safety initiatives** (e.g., One Stop Centres, Nirbhaya Fund) - This is unrelated to the water supply mandate of Swajaldhara *Provision of health care for sick tribals* - Health care for tribal populations is managed through dedicated programs under the Ministry of Health and Family Welfare - Swajaldhara's scope was limited to **rural drinking water infrastructure**, not healthcare delivery

Practice by Chapter

Water Quality and Health

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Air Pollution and Health Effects

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Solid Waste Management

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Hazardous Waste Management

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Housing and Health

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Noise Pollution

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Radiation Health Effects

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Climate Change and Health

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Environmental Impact Assessment

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Disaster Management and Preparedness

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Vector Control

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Environmental Legislation

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