Which international convention, adopted in 2013, aims to protect human health from anthropogenic emissions of mercury?
- Basel Convention
- Stockholm Agreement
- Rotterdam Accord
- Minamata Treaty
Explanation: The Minamata Convention on Mercury is a global treaty designed to phase out mercury use and prevent water contamination.
Chronic exposure to which metalloid through groundwater causes 'Blackfoot disease'?
- Arsenic
- Cadmium
- Mercury
- Lead
Explanation: Prolonged exposure to arsenic in drinking water causes skin lesions and peripheral vascular disease known as Blackfoot disease.
The use of specific plants to remove, transfer, or stabilize heavy metal contaminants in soil and water is known as:
- Phytoremediation
- Bacterial degradation
- Chemical scrubbing
- Mycoremediation
Explanation: Phytoremediation employs plants like water hyacinths to absorb heavy metals and pollutants from contaminated water.
What happens to the Biological Oxygen Demand (BOD) of a river immediately downstream from a raw sewage discharge point?
- Fluctuates quite randomly
- Increases sharply
- Remains totally constant
- Decreases very sharply
Explanation: The sudden influx of organic matter causes a population explosion of decomposing bacteria, which rapidly consume oxygen (spiking the BOD).
Acid mine drainage severely pollutes water bodies by making them highly acidic and dangerously rich in:
- Dissolved heavy metals
- Radioactive heavy isotopes
- Suspended organic matter
- Fecal coliform bacteria
Explanation: The highly acidic water leaches toxic heavy metals like lead, copper, and iron from the surrounding rock, poisoning downstream waters.
Which international convention specifically deals with the prevention of marine pollution from ships?
- Basel Convention
- Ramsar Convention
- MARPOL Convention
- Minamata Treaty
Explanation: The International Convention for the Prevention of Pollution from Ships (MARPOL) is the main international convention covering prevention of pollution of the marine environment by ships.
Chlorination of drinking water containing organic matter can unintentionally produce carcinogenic byproducts known as:
- Nitrosamine groups
- Chloramine compounds
- Trihalomethanes
- Polyaromatic rings
Explanation: Trihalomethanes (THMs) are formed when chlorine reacts with naturally occurring organic matter in the water supply.
Which statutory body was created in 2016 to oversee the implementation of the Namami Gange Programme?
- The NGT
- The CGWB
- The NMCG
- The CPCB
Explanation: The National Mission for Clean Ganga (NMCG) acts as the implementation wing of the National Ganga Council.
The massive accumulation of marine debris known as the Great Pacific Garbage Patch is primarily trapped by circulating ocean currents called a:
- Gyre
- Tsunami
- Monsoon
- Trench
Explanation: Ocean gyres are massive, circular current systems that trap floating plastics and debris in their calm centers.
The presence of which dissolved gas is critical for the survival of most aquatic life and indicates good water quality?
- Nitrogen gas
- Carbon dioxide
- Hydrogen sulfide
- Dissolved oxygen
Explanation: Adequate Dissolved Oxygen (DO) is essential for aerobic aquatic organisms; its depletion leads to fish kills and dead zones.
Harmful Algal Blooms (HABs) that produce neurotoxins and deplete oxygen are frequently referred to as:
- Black sea
- Brown tides
- Red tides
- Green algal mats
Explanation: Red tides are caused by explosive growth of certain dinoflagellates that color the water and release deadly toxins.
Which term describes the leakage of contaminated liquid from a solid waste landfill into the underlying groundwater?
- Mine tailings
- Sewage sludge
- Leachate
- Toxic effluent
Explanation: Leachate is the toxic liquid that drains or 'leaches' from a landfill, requiring specialized collection and treatment.
According to the Bureau of Indian Standards (BIS), what is the maximum desirable limit of fluoride in drinking water?
- 0.5 mg/L
- 2.0 mg/L
- 1.0 mg/L
- 5.0 mg/L
Explanation: The BIS sets the acceptable limit of fluoride at 1.0 mg/L, extending to 1.5 mg/L only in the absence of an alternate source.
The Central Pollution Control Board (CPCB) of India was originally constituted under which environmental legislation?
- Air Act
- Environment Protection Act
- NGT Act
- Water Act
Explanation: The CPCB was constituted in September 1974 under the Water (Prevention and Control of Pollution) Act, 1974.
Eutrophication leads to rapid plant growth. Which floating weed famously choked Indian water bodies, earning the name 'Terror of Bengal'?
- Water hyacinth
- Common duckweed
- Giant salvinia
- Hydrilla verticillata
Explanation: Water hyacinth (Eichhornia crassipes) is an invasive aquatic plant that forms dense mats, blocking sunlight and oxygen.
Which specific pathogen, often found in untreated sewage, causes the deadly infectious disease cholera?
- Viral pathogens
- Vibrio bacteria
- E coli bacteria
- Amoeba parasites
Explanation: Vibrio cholerae is the bacterium responsible for cholera, which spreads rapidly through fecally contaminated water.
Which advanced water purification technology uses a semi-permeable membrane to remove ions and molecules from drinking water?
- Reverse osmosis
- Ozonation treatment
- Ultraviolet irradiation
- Activated carbon filter
Explanation: Reverse osmosis (RO) applies pressure to overcome osmotic pressure, forcing water through a membrane that blocks heavy metals and salts.
The presence of sludge worms (Tubifex) in a water body serves as a biological indicator of:
- Organic pollution
- Metal toxicity
- Pure pristine water
- High oxygen level
Explanation: Tubifex worms can survive in highly polluted, oxygen-poor water with high organic matter, making them classic indicators of sewage pollution.
The leather tanning industry, particularly in regions like Kanpur, is notorious for polluting the Ganga river with which highly toxic heavy metal?
- Polychlorinated biphenyls
- Methylated mercury
- Hexavalent chromium
- Inorganic arsenic
Explanation: Hexavalent chromium is widely used in leather tanning and is a highly toxic, carcinogenic water pollutant.
An eco-friendly technology called 'Oilzapper' used to clean up marine oil spills, essentially consists of a consortium of:
- Fungi
- Protozoa
- Algae
- Bacteria
Explanation: Developed by TERI, Oilzapper is a cocktail of bacteria that feed on hydrocarbon compounds present in crude oil.
Recent studies in India have found widespread groundwater contamination of which radioactive element, especially in Punjab and Rajasthan?
- Thorium
- Uranium
- Plutonium
- Radium
Explanation: Geogenic factors and agricultural practices have led to alarming levels of uranium in the groundwater of several Indian states.
What is the primary environmental danger of using organochlorine pesticides like DDT near water bodies?
- Ozone layer depletion
- High water solubility
- Rapid water evaporation
- Extreme persistence
Explanation: Organochlorines resist degradation, persisting in the environment for decades and biomagnifying up the food chain.
The amount of dissolved oxygen consumed by microorganisms to decompose organic matter in a water body is termed:
- Oxygen saturation
- Biological demand
- Dissolved oxygen
- Chemical oxygen demand
Explanation: Biological Oxygen Demand (BOD) is a measure of the amount of oxygen required by aerobic microorganisms to decompose organic matter.
Water with high concentrations of dissolved minerals, specifically calcium and magnesium ions, is called:
- Soft water
- Saline water
- Heavy water
- Hard water
Explanation: Hard water causes scaling in pipes and reduces the lathering ability of soap, though it is not generally a health hazard.
Which heavy metal, frequently used in small-scale artisanal gold mining, causes severe neurotoxic water pollution?
- Hexavalent chromium
- Elemental mercury
- Radioactive uranium
- Inorganic arsenic
Explanation: Mercury is used to extract gold from ore; it washes into rivers where it transforms into highly toxic methylmercury.
Water pollution originating from a single, identifiable source, such as an industrial discharge pipe, is termed a:
- Non point source
- Area level source
- Point source
- Diffuse pollution
Explanation: Point source pollution is easy to identify, monitor, and regulate because it comes from a specific, localized origin.
Increasing concentration of a toxic substance at successive trophic levels in an aquatic food chain is called:
- Biomagnification
- Bioaccumulation
- Bioremediation
- Ecological succession
Explanation: Biomagnification refers to the magnification of toxin concentration (like DDT or mercury) as it passes up the food chain.
'Black water' is a wastewater terminology specifically used to describe highly polluted wastewater originating from:
- Industrial cooling
- Laundry wash machines
- Kitchen drain sinks
- Bathroom toilets
Explanation: Black water contains human waste and dangerous pathogens, requiring intense biological treatment before discharge.
Hypoxic areas in oceans and large lakes, caused by excessive nutrient pollution leading to oxygen depletion, are commonly known as:
- Dead zones
- Barren seas
- Hypoxic death zones
- Toxic zones
Explanation: Dead zones contain so little oxygen that marine life either dies or is forced to migrate away.
The 'MPN' test is a standard method used to estimate the concentration of viable coliform bacteria in a water sample. What does MPN stand for?
- Mean Pollution Number
- Most Probable Number
- Maximum Permissible Number
- Minimum Pathogen Number
Explanation: MPN is a statistical method used to estimate the number of viable microorganisms in a sample, crucial for testing water potability.
Plastic particles smaller than 5 millimeters in length, often found polluting marine and freshwater ecosystems, are defined as:
- Mesoplastics
- Microplastics
- Nanoplastics
- Large macroplastics
Explanation: Microplastics result from the breakdown of larger plastics or are manufactured as microbeads, posing a severe threat to aquatic life.
Which two nutrients are the primary drivers of cultural eutrophication in freshwater lakes?
- Dissolved organic carbon
- Nitrogen and phosphorus
- Iron and manganese
- Carbon and sulfur
Explanation: Excessive nitrogen and phosphorus from agricultural runoff stimulate massive algal blooms, leading to eutrophication.
The discharge of nutrient-rich agricultural runoff into coastal waters often leads to severe hypoxia, creating:
- Toxic algal blooms
- Severe tidal waves
- Massive coral reefs
- Dead zones
Explanation: Dead zones are areas in the ocean or large lakes where oxygen levels are too low to support most marine life.
Which technique uses an electric current to remove suspended heavy metals and colloids from industrial wastewater?
- Reverse osmosis
- Carbon filtering
- Electrocoagulation
- UV irradiation
Explanation: Electrocoagulation introduces a direct current into wastewater to destabilize and coagulate contaminants for easy removal.
Thermal pollution from power plants decreases oxygen solubility, while simultaneously increasing the aquatic organisms':
- Reproductive success
- Total lifespan
- Metabolic rate
- Average body size
Explanation: Warmer water accelerates cold-blooded animals' metabolisms, making them require more oxygen exactly when the water holds less of it.
Which index is commonly used by environmental agencies to summarize various water quality parameters into a single, easy-to-understand number?
- Pollution Standard Index
- Water Quality Index
- Biotic Index Number
- Ecological Footprint Score
Explanation: The Water Quality Index (WQI) translates complex data (pH, BOD, dissolved oxygen) into a single score rating the water's overall health.
A Secchi disk is a standard tool used by hydrologists and limnologists to measure which property of a water body?
- pH level
- Dissolved oxygen
- Water temperature
- Water turbidity
Explanation: A Secchi disk is lowered into the water to measure transparency or turbidity based on when it disappears from sight.
In municipal wastewater treatment, the biological process used to degrade organic matter is categorized as:
- Tertiary treatment
- Advanced processing
- Secondary treatment
- Primary treatment
Explanation: Secondary treatment utilizes aerobic bacteria and other microorganisms to break down dissolved and suspended organic organic matter in sewage.
Permanent hardness in water is primarily caused by the presence of chlorides and sulfates of:
- Bicarbonate and sulfate
- Copper and lead
- Sodium and potassium
- Calcium and magnesium
Explanation: Permanent hardness cannot be removed by boiling and is caused by dissolved calcium and magnesium sulfates or chlorides.
Plumbism is a severe systemic toxicity condition caused by water or environmental pollution involving which metal?
- Lead
- Mercury
- Arsenic
- Cadmium
Explanation: Plumbism, or lead poisoning, affects the nervous system and is historically linked to lead pipes and industrial effluents.
Minamata disease, a severe neurological syndrome, is caused by severe water pollution from which heavy metal?
- Lead compound
- Methylmercury
- Cadmium sulfate
- Arsenic oxide
Explanation: Minamata disease was first discovered in Minamata city in Japan, caused by the release of methylmercury in industrial wastewater.
Endocrine-disrupting chemicals (EDCs) in water pollution are notorious for interfering with aquatic animals':
- Respiratory gill organs
- Hormone systems
- Digestive tract system
- Skeletal bone growth
Explanation: EDCs mimic or block natural hormones, causing severe reproductive abnormalities and feminization in fish and amphibians.
In wastewater treatment, the physical removal of large floating objects using grates and screens occurs during:
- Primary treatment
- Secondary treatment
- Tertiary treatment
- Biological phase
Explanation: Primary treatment is the mechanical or physical phase where solid pollutants are removed via screening and sedimentation.
Synthetic microfibers, a major source of microplastic water pollution, primarily originate from:
- Degrading car tires
- Cosmetic microbeads
- Washing clothes
- Discarded fish nets
Explanation: Washing synthetic garments like polyester sheds millions of microscopic plastic fibers into the wastewater system.
'Grey water' refers to domestic wastewater from sinks and showers that does NOT contain significant levels of:
- Fecal matter
- Human hair fibers
- Soap residue foam
- Cooking oil grease
Explanation: Grey water is relatively clean wastewater that lacks heavy fecal contamination, making it easier to recycle for gardening.
A major environmental drawback of using Reverse Osmosis (RO) systems for domestic water purification is the generation of:
- Concentrated salt brine
- Toxic ozone gas
- Nonbiodegradable toxic sludge
- Heavy metal sludge
Explanation: RO filters reject heavily concentrated brine (reject water), which is often wasted or pollutes local soil and water tables.
Mottling of teeth and crippling bone deformities are the primary symptoms of prolonged consumption of water rich in:
- Lead
- Arsenic
- Methylmercury
- Fluoride
Explanation: High fluoride levels in groundwater lead to dental and skeletal fluorosis, a major public health issue in several Indian states.
Groundwater in the state of West Bengal is severely affected by the natural, geogenic presence of which highly toxic metalloid?
- Mercury toxins
- Lead metal
- Arsenic
- Cadmium
Explanation: The Ganga-Brahmaputra delta region faces severe arsenic contamination in groundwater due to geological formations.
Healthy 'Oligotrophic' lakes are characterized by deep, clear waters and naturally low levels of:
- Radioactive isotopes
- Dissolved oxygen gas
- Dissolved nutrients
- Toxic heavy metals
Explanation: Oligotrophic lakes have low nutrient concentrations, restricting excessive plant growth and maintaining clear water.
Persistent Organic Pollutants (POPs), which accumulate in water bodies, are regulated globally by the:
- Basel agreement
- Vienna accord
- Stockholm treaty
- Rotterdam pact
Explanation: The Stockholm Convention is a global treaty to protect human health and the environment from chemicals that remain intact in the environment for long periods.
The presence of which specific bacteria in a water body is universally used as an indicator of fecal contamination?
- Streptococcus
- Vibrio cholerae
- Salmonella
- E. coli
Explanation: Escherichia coli is a coliform bacterium found in the intestines of warm-blooded animals; its presence indicates sewage pollution.
Methemoglobinemia, commonly known as 'Blue Baby Syndrome', is caused by high levels of which contaminant in drinking water?
- Nitrates
- Chlorides
- Phosphates
- Sulfates
Explanation: Excessive nitrates in drinking water restrict oxygen transport in the blood, leading to a blueish tint in infants.
The gradual accumulation of a toxic substance in the tissue of a single organism over its lifetime is termed:
- Ecological succession
- Bioaccumulation
- Biomagnification
- Eutrophication
Explanation: Unlike biomagnification (which occurs across a food chain), bioaccumulation occurs within an individual organism.
The National Water Quality Monitoring Programme in India is executed by which apex regulatory body?
- The CWC
- The CPCB
- The CGWB
- The MoEFCC
Explanation: The Central Pollution Control Board (CPCB) oversees a vast network of water quality monitoring stations across India.
The 'Itai-Itai' disease, first recognized in Japan, was caused by the industrial discharge of which metal into rivers?
- Cadmium
- Arsenic
- Mercury
- Fluoride
Explanation: Itai-itai disease was caused by cadmium poisoning, resulting in softening of the bones and kidney failure.
Which synthetic chemicals, known as 'forever chemicals' due to their extreme persistence in water, are widely used in non-stick cookware?
- PFAS compounds
- Organochlorine gas
- Polychlorinated biphenyls
- Phthalate esters
Explanation: Per- and polyfluoroalkyl substances (PFAS) do not break down in the environment and have heavily contaminated groundwater globally.
The primary adverse effect of thermal pollution (discharging hot water from power plants) on aquatic life is the sudden decrease in:
- Dissolved oxygen
- Pathogen levels
- Total dissolved solids
- Water salinity
Explanation: Warm water holds significantly less dissolved oxygen than cold water, suffocating aquatic organisms.
The Water (Prevention and Control of Pollution) Act was enacted by the Parliament of India in which year?
- 1981 Act
- 1986 Act
- 1972 Act
- 1974 Act
Explanation: The Water Act was enacted in 1974 to prevent and control water pollution and maintain the wholesomeness of water.
Which metric measures both biodegradable and non-biodegradable organic pollutants in a water sample?
- Chemical oxygen demand
- Biological oxygen demand
- Total dissolved solids
- Dissolved oxygen level
Explanation: COD measures the total amount of oxygen required to chemically oxidize all organic materials, making it generally higher than BOD.
An industrial wastewater management strategy that ensures no untreated effluent is released into the environment is called:
- Zero liquid discharge
- Primary treatment
- Secondary treatment
- Total water recycling
Explanation: Zero Liquid Discharge (ZLD) is a process that recovers all water from industrial wastewater, leaving behind only solid waste.