Environmental Health — MCQs

Environmental Health Indian Medical PG Practice Questions and MCQs

Question 671: Process of mixing waste with cement before disposal is known as -

A. Inertization (Correct Answer)
B. Burial
C. Sanitary landfill
D. Controlled tipping

Explanation: ***Inertization*** - **Inertization** is a process that involves mixing waste, often hazardous, with a binding agent like **cement** to create a stable, solid matrix. - This method aims to **reduce the mobility of hazardous substances**, making them less likely to leach into the environment after disposal. *Burial* - **Burial** is a general term for placing waste underground, but it doesn't necessarily involve mixing with cement. - It often refers to simple disposal in pits or trenches without special treatment to stabilize the waste. *Sanitary landfill* - A **sanitary landfill** is an engineered facility for disposing of solid waste that minimizes harm to the environment. - While it involves careful layering and covering, it typically does not involve pre-mixing waste with cement as a primary treatment method for all waste. *Controlled tipping* - **Controlled tipping** is an older term for a method of waste disposal where waste is deposited in layers and covered with soil, similar to basic landfill practices. - It does not specifically refer to the chemical or physical treatment of waste with cement to render it inert.

Question 672: Methylene blue reduction test is done for estimating –

A. Fat content of milk
B. Protein content of milk
C. Sugar content of milk
D. Bacterial activity in milk (Correct Answer)

Explanation: ***Bacterial activity in milk*** - The **methylene blue reduction test (MBRT)** is a rapid and inexpensive method used to estimate the **bacterial load** in milk. - **Bacteria** in milk consume oxygen, creating a reducing environment that causes the blue methylene blue dye to decolorize. The faster the decolorization, the higher the bacterial count. *Fat content of milk* - The **fat content** of milk is typically determined using methods like the **Gerber test** or **Babcock method**, which involve acid digestion and centrifugation. - MBRT does not directly measure the amount of fat present in the milk sample. *Protein content of milk* - **Protein content** in milk is commonly measured using methods such as the **Kjeldahl method** or infrared analysis. - The MBRT is not designed to quantify the protein components of milk. *Sugar content of milk* - The **sugar content**, primarily **lactose**, in milk is measured using enzymatic assays or chromatographic methods. - MBRT does not provide information about the lactose concentration.

Question 673: During water analysis in a hostel, amoebic cysts were seen. The best step to manage it is:

A. UV Rays
B. Boiling (Correct Answer)
C. Chlorination
D. Iodine

Explanation: **Boiling** - Boiling water at 100°C for at least one minute is highly effective in **killing amoebic cysts**, including *Entamoeba histolytica*, by denaturing their proteins and disrupting their structure. - This method ensures the **destruction of viable cysts**, preventing waterborne transmission of amoebiasis among hostel residents. *UV Rays* - While UV radiation can inactivate many microorganisms, its effectiveness against **amoebic cysts** can be inconsistent, as cysts are more resistant than bacteria or viruses. - The efficacy depends on the **dose and turbidity of the water**, which can shield cysts from UV light. *Chlorination* - **Amoebic cysts are highly resistant to standard chlorine levels** typically used in water disinfection. - Significantly higher doses and longer contact times of chlorine would be required to kill cysts, which may not be practical or safe for drinking water due to the formation of **disinfection byproducts**. *Iodine* - Iodine can kill some pathogens, but its efficacy against **amoebic cysts is variable and often insufficient** at concentrations safe for consumption. - It may not reliably kill all cysts, especially at **lower temperatures or shorter contact times**.

Question 674: Solid waste contaminated with blood and body fluids is classified under which category according to Bio-Medical Waste Management Rules?

A. 6 (Correct Answer)
B. 9
C. 5
D. 3

Explanation: ***Correct: Category 6*** - According to the **Bio-Medical Waste Management Rules, 2016**, solid waste contaminated with blood and body fluids is categorized under **Category 6**. - This includes items like **dressings, plaster casts, cotton swabs, and bags containing residual or discarded blood and blood components**. - These items require specific handling and disposal methods as they pose infection risk due to visible soiling or soaking with blood and bodily fluids. *Incorrect: Category 9* - Category 9 refers to **discarded linen, mattresses, and beddings contaminated with blood or body fluids**. - While also dealing with blood-contaminated materials, this category is specifically for textile/fabric items, not general solid waste like dressings and swabs. *Incorrect: Category 5* - Category 5 covers **discarded medicines and cytotoxic drugs**, including expired, discarded, or contaminated pharmaceutical products. - This category deals with pharmaceutical waste, not materials contaminated with blood and body fluids. *Incorrect: Category 3* - Category 3 is designated for **microbiology, biotechnology, and other clinical laboratory waste**, including laboratory cultures, stocks or specimens of microorganisms, live or attenuated vaccines, and human and animal cell cultures. - This category focuses on infectious biological agents and laboratory waste, not general solid waste contaminated with blood and body fluids.

Question 675: In which color bag should the plastic wrapper of a surgical syringe be discarded?

A. Black bag
B. Red bag
C. Yellow bag (Correct Answer)
D. Blue bag

Explanation: ***Yellow bag*** - The plastic wrapper of a surgical syringe should be discarded in a **yellow bag** according to **Biomedical Waste Management Rules, 2016**. - Yellow bags are designated for **waste sharps including metals, plastics and glass** - specifically **non-chlorinated plastic waste** that has not been contaminated with blood or body fluids. - The wrapper is removed **before** the syringe is used, so it has **no patient contact** and is considered **non-infectious** plastic waste suitable for recycling or disposal. - As per **Category 7** of BMW Rules: Discarded and contaminated plastics are different from **unused wrappers** which are clean plastic waste. *Red bag* - **Red bags** are designated for **contaminated waste** (Category 3 & 6) including items soaked with blood, body fluids, or infectious materials like used gloves, blood-soaked cotton, tubing, catheters **after patient use**. - The plastic wrapper is discarded **immediately after opening** and has **no contact** with patient fluids, so it does not qualify as contaminated waste. - Only the **used syringe components** that contacted the patient would be infectious waste. *Yellow bag (Sharps)* - While yellow bags/containers are used for **sharps** (needles, scalpels, blades), the **yellow bag category** also includes non-sharp plastic waste. - The used needle itself goes into a **puncture-proof sharps container** (also marked yellow), but the wrapper goes in the yellow bag for plastics. *Blue bag* - **Blue/White translucent bags** are used for **glassware, metallic body implants** and other materials that can be autoclaved and recycled (Category 5). - Plastic wrappers do not fall into this category as they are not meant for autoclaving.

Question 676: The size of Respirable dust is -

A. 1-5 microns (Correct Answer)
B. 5-10 microns
C. 20 microns
D. 15 microns

Explanation: ***1-5 microns*** - **Respirable dust** refers to particles tiny enough to penetrate the deepest parts of the lungs, specifically the **alveoli**. - Particles within the **1-5 micron** range are considered most effective at reaching these deep lung regions, posing significant health risks. *5-10 microns* - Particles in this range are generally considered **thoracic dust**, which can reach the lower airways and bronchi. - While they can cause respiratory issues, they are less likely to penetrate to the **alveolar level** compared to respirable dust. *20 microns* - Particles of **20 microns** are typically too large to be considered respirable dust. - They are mostly deposited in the **upper respiratory tract** (nose and throat) and cleared by mucociliary action, rarely reaching the deeper lungs. *15 microns* - Similar to 20-micron particles, **15-micron** dust particles are largely deposited in the upper airways. - They are generally too large to effectively penetrate into the **alveoli** and thus are not classified as respirable dust.

Question 677: Which bag among the following shouldn't be incinerated as it contains cadmium?

A. Black
B. Red (Correct Answer)
C. Yellow
D. Blue

Explanation: ***Correct Option: Red*** - **Red bags** are designated for **contaminated recyclable waste** including plastic items (IV sets, catheters, blood bags without blood). - Red bag waste should be **autoclaved/disinfected first, then recycled or shredded** - NOT incinerated. - Incineration of plastic waste releases **toxic compounds including dioxins, furans**, and potentially **cadmium** (from plastic additives) into the atmosphere. - The cadmium content in certain plastics makes incineration particularly hazardous, violating environmental safety protocols. *Incorrect Option: Yellow* - **Yellow bags** contain infectious and anatomical waste that is **specifically meant for incineration** or deep burial. - These are disposed through **incineration, plasma pyrolysis, or deep burial** as per BMW Rules. - Yellow bag incineration is the standard protocol for pathological and infectious waste. *Incorrect Option: Blue/White* - **Blue/White bags** are for **sharps waste** (needles, scalpels, broken glass). - Sharps are treated by **autoclaving, microwaving, or chemical disinfection**, then disposed in sanitary landfills. - Not typically incinerated due to glass and metal content. *Incorrect Option: Black* - **Black bags** contain **general non-hazardous waste** similar to municipal solid waste. - Disposed through **sanitary landfills**, not incineration. - Does not require specialized biomedical waste treatment.

Question 678: A good trap should have an effective seal of:

A. 2.5 cm
B. 5 cm (Correct Answer)
C. 10 cm
D. 7.5 cm

Explanation: ***5 cm*** - A good trap seal is designed to provide a sufficient **water barrier** to prevent the entry of **sewer gases** into a building. - A 5 cm seal is generally considered the **standard minimum depth** to effectively block these gases under normal operating conditions. *2.5 cm* - A 2.5 cm seal is generally considered **insufficient** as it may be susceptible to **siphonage** or rapid evaporation, leading to the loss of the water barrier. - This shallow depth increases the risk of **sewer gas entry**, posing a public health hazard. *10 cm* - While a 10 cm seal would provide an effective barrier, it is often **unnecessary** and can lead to **slower drainage** and inefficient fixture operation. - A deeper seal also requires more water to maintain, increasing potential for **clogging** and making it less practical for standard plumbing applications. *7.5 cm* - A 7.5 cm seal is generally **acceptable** and offers a good balance between effectiveness and practicality, but 5 cm is typically the minimum standard. - While robust, it is still considered **more than the common minimum requirement** without significant additional benefits over a 5 cm seal for most applications.

Question 679: Orthotolidine test is used to determine ?

A. Nitrates in water
B. Nitrites in water
C. Ammonia content in water
D. Free and combined chlorine in water (Correct Answer)

Explanation: ***Free and combined chlorine in water*** - The **orthotolidine test** is a **colorimetric method** used to measure the concentration of **residual chlorine** in water. - It reacts with both **free available chlorine** (hypochlorous acid and hypochlorite ions) and **combined available chlorine** (chloramines) to produce a **yellow color**. *Nitrates in water* - **Nitrates** are typically measured using methods like **cadmium reduction** or **UV spectrophotometry**, not the orthotolidine test. - High nitrate levels can indicate **agricultural runoff** or **sewage contamination**. *Nitrites in water* - **Nitrites** are commonly detected using the **Griess reagent method**, which produces a red-pink color. - The orthotolidine test is not designed to detect nitrites. *Ammonia content in water* - **Ammonia** is usually determined by methods such as the **Nessler method** or **ion-selective electrodes**. - These methods involve specific chemical reactions distinct from the orthotolidine reaction.

Question 680: Safe disposal of mercury is:

A. Treatment with chemicals
B. Collect carefully and recycle (Correct Answer)
C. Controlled combustion
D. Deep burial

Explanation: ***Collect carefully and recycle*** - **Recycling** is the preferred method for safe mercury disposal as it prevents its release into the environment and allows for reuse. - Careful collection minimizes exposure and contamination, which are crucial due to mercury's **toxicity**. *Treatment with chemicals* - While some chemical treatments can solidify or neutralize mercury, this is typically part of a broader **remediation or stabilization process**, not the primary safe disposal method for consumer waste. - Direct chemical treatment of mercury without proper facilities can be dangerous and produce hazardous byproducts, making it unsuitable for general disposal. *Controlled combustion* - **Combustion of mercury** is highly dangerous as it vaporizes, releasing toxic mercury fumes and **mercury oxides** into the atmosphere. - This method would exacerbate environmental pollution and health risks, making it an entirely unsafe disposal option. *Deep burial* - **Deep burial** of mercury can lead to its leaching into groundwater and soil over time, causing widespread environmental contamination. - Mercury is a persistent pollutant; once buried, it can transform into **methylmercury**, a highly toxic form that bioaccumulates in the food chain.

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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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