Environment and Environmental Hygiene (Water) Question Answers
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| Environment and Environmental Hygiene (Water) MCQS |
Part 1:
MULTIPLE CHOICE QUESTIONS
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- Safe and wholesome water is defined as the water that is
a. free from pathogenic agents
b. free from harmful chemical substances
c. pleasant to taste
d. usable for domestic purposes
e. all the above
ANS: e - Rain water is very soft water containing __________ per cent of dissolved solids
a. 0.00005
b. 0.0005
c. 0.000005
d. 0.005
ANS: b - The area draining into the reservoir is called as __________
a. Collection area
b. Attached area
c. Catchment area
d. Draining area
ANS: c - Agents of self purification in river include __________
a. Dilution and sedimentation
b. Aeratiuon and Oxidation
c. Sunlight, plant and animal life
d. All the above
ANS: d - Salt content in sea water is __________ percent
a. 7.5
b. 6.5
c. 3.5
d. 2.5
ANS: c - Deep wells tap water from __________
a. Water above the first impervious strata
b. Water from first porous strata
c. Water below the first impervious strata
d. Water below the second impervious strata
ANS: c - Katcha wells and Pucca wells are examples for __________
a. Tube wells
b. Dug wells
c. Step well
d. None of the above
ANS: b - __________ disease is a public health problem in areas where step wells are in use.
a. Cholera
b. Taeniais
c. Guinea worm
d. E. coli
ANS: c - To avoid bacterial contamination a sanitary well should be located __________ from likely sources of contamination.
a. 15 m
b. 50 feet
c. 10 m
d. both a &b
ANS: d - A sanitary well should have a parapet wall of at least __________ height above the ground.
a. 90-95 cm
b. 70-75 cm
c. 50-55 cm
d. 100-110 cm
ANS: b - Hardness of water appears to have a beneficial effect against __________ diseases
a. Neurological
b. Cardiovascular
c. Muculoskeletal
d. Reproductive
ANS: b - Water (Prevention and Control of Pollution) Act was passed in the year __________
a. 1974
b. 1964
c. 1978
d. 1968
ANS: a - The optimum period of storage of river water for purification is __________ days
a. 1-2
b. 3-7
c. 8-9
d. 10-14
ANS: d - Which among the following is not a part of slow sand filter or biological filter
a. supernatant (raw) water
b. a bed of graded sand
c. an under-drainage system
d. a system of filter control valves
e. none of the above
ANS: e - The depth of supernatant water above the sand bed in slow sand filter is __________ metre
a. 0.5-1
b. 1-1.5
c. 2-3
d. 3-5
ANS: b - Supernatant water provides a waiting of __________ hours, depending on the filtration velocity
a. 1-2
b. 3-12
c. 12-24
d. 24-48
ANS: b - The effective diameter of sand grains in slow sand filter is __________ mm
a. 0.2-0.3
b. 0.4 -0.7
c. 0.8-1
d. 1-1.5
ANS: a - The rate of filtration of water in case of a biological filter normally lies between __________ cubic metre/hour/per square metre of sand bed surface.
a. 0.1-0.4
b. 0.02-0.04
c. 5-15
d. 20-25
ANS: a - Ripening of biological filter means __________
a. completion of purification
d. time to close down the filter plant
c. formation of vital layer/schmutzdecke/zoogleal layer or biological layer
d. removal of vital layer/schmutzdecke/zoogleal layer or biological layer
ANS: c - Heart of biological filter is __________
a. vital layer
b. gravel support
c. filter control
d. under-drainage system
ANS: a - Venturi meter of the regulation system in the slow sand filter measures __________
a. rate of filtration
b. rate of oxidation
c. bed resistance or loss of head
d. rate of reduction in BOD
ANS: c - Which among the following statements are wrong?
a. Paterson’s filter is a gravity type rapid sand filter
b. Candy’s filter is a pressure type rapid sand filter
c. Alum is used as a chemical coagulant
d. Rapid sand filter is also known as biological filter
ANS: d - The correct sequence of steps in rapid sand filtration is as :
a. coagulation, rapid mixing, flocculation, sedimentation, filtration
b. rapid mixing, coagulation, flocculation, sedimentation, filtration
c. flocculation, coagulation, rapid mixing, sedimentation, filtration
d. coagulation, rapid mixing, flocculation, filtration, sedimentation
ANS: a - The time allotted for sedimentation in case of rapid sand filter is __________ hours
a. 0.5-1
b. 2-6
c. 8-10
d. 12-24
ANS: b - The effective diameter of sand grains in rapid sand filter is __________ mm
a. 0.2-0.3
b. 0.4 -0.7
c. 0.8-1
d. 1-1.5
ANS: b - The rate of filtration of water in case of a biological filter normally lies between __________ cubic metre/ square metre/hour
a. 0.1-0.4
b. 0.02-0.04
c. 5-15
d. 20-25
ANS: c - Which among the following statements are wrong?
a. Washing of slow-sand filter is by scrapping the sand bed
b. Washing of rapid sand filter is by back-washing
c. Loss of head allowed in slow sand filter is 4 feet
d. Loss of head allowed in rapid sand filter is 6-8 feet
e. None of the above
ANS: e - Rapid sand filter removes __________ per cent of bacteria
a.90-95
b.95-96
c. 98-99
d.99.9-99.99
ANS: c - Slow sand filter removes __________ per cent of bacteria
a.90-95
b.95-96
c. 98-99
d.99.9-99.99
ANS: d - Which among the following are the properties of chlorine?
a. kills pathogenic bacteria and aids coagulation
b. oxidises iron, manganese and hydrogen sulphide
destroys some taste and odour producing constituents
d. controls algae and slime organisms
e. all the above
ANS: e - the disinfecting action of chlorine is mainly due to __________
a. Hypochloric acid
b. Hypochlorous acid
c. Hypochlorite ion
d. Hydrochloric acid
ANS: b - Chlorine act best as a disinfectant when the pH of water is around __________
a. 9
b. 10
c. 7
d. 5
ANS: c - The difference between the amount of chlorine added to the water, anfd the amount of chlorine remaining at the end of a specific contact time at a given temperature and pH of water is called as __________
a. Break point
b. Chlorine demand
c. Residual chlorine
d. Superchlorination
ANS: b - The usual contact time of chlorination of water is __________ minutes
a. 30
b. 60
c. 120
d 180
ANS: b - The poimt at which the chlorine demand of the water is met or the point at which at which all combined chlorines have been disappeared and residual chlorine appears is called __________
a. Break point
b. Chlorine demand
c. Bleaching
d. Superchlorination
ANS: a - Chlorine has no effect on __________ at usual doses.
a. Spores
b. Protozoal cysts
c. Helminthic ova
d. All the above
ANS: d - The minimum recommended concentration of free chlorine is __________ mg/L for one hour
a. 0.5
b. 1
b. 5
c. 10
ANS: a - Paterson’s chloranome is a device used for measuring, regulating and administering __________ to water supplies.
a. Chloramine
b. Perchloron
c. Chlorine gas
d. Bleaching powder
ANS: c - __________ are loose compounds of chlorine and ammonia
a. Chloramine
b. Perchloron
c. Chlorine gas
d. Bleaching powder
ANS: a - Perchloron or high test hypochlorite ( H.T.H) is a __________ compound which carries 60-70 per cent of available chlorine.
a. Calcium
b. Magnesium
c. Sodium
d. Potassium
ANS: a - The type of chlorination suitable for heavily polluted water is __________
a, Break-point chlorination
b. Superchlorination
c. Chloramine
d. Perchloron
ANS: b - Which among the following statements regarding orthotolidine test is wrong?
a. Enables both free and combined chlorine in water to be determined
b. OT reacts with free chlorine instantaneously but reacts more slowly with combined chlorine producing yellow color
c. OTA ( Orthotolidine-Arsenite test) is a modification of of OT test to determine the free and combined chlorine seperatedly
d. The errors caused by the presence of nitrates, iron and manganese which also produce yellow color are overcome by OTA test
e. OT test was developed in 1938
ANS: e - The contact time in case of ozonation is __________ minutes
a. 1-5
b. 10-20
c. 30-60
d. 60-120
ANS: b - The dose of ozone in case of ozonation is typically in the range of __________ mg/L
a. 0.5-1
b. 1-2
c. 2-5
d. 6-10
ANS: c - Typical operating pressure in case of reverse osmosis is in the range of __________ bar.
a. 1-5
b. 5-10
c. 15-50
d. 50-100
ANS: c - Reverse osmosis rejects monovalent ions and organics of molecular weight greater than about __________ daltons.
a. 10
b. 50
c. 100
d. 200
ANS: b - Which among the pore size of the membranes is not matching with the membrane process?
a. Reverse osmosis : < 0.002 micron
b. Nanofiltration: 0.001-0.01 micron
c. Ultrfiltration: 0.002-0.03 micron
d. Microfiltration: 0.01-0.12 micron
e. None of the above
ANS: e - Bleaching powder or chlorinated lime contains a __________ per cent of available chlorine.
a. 23
b. 33
c. 37
d. 43
ANS: b - Halazone tablet is a __________ containing tablet
a. Chlorine
b. ozone
c. Amine
d. Potassium permanganate
ANS: a - __________ is used for the emergency disinfection of water
a. Chlorine
b. Ozone
c. Iodine
d. Radiation
ANS: c
REFERENCE:
PARK’S TEXTBOOK OF PREVENTIVE AND SOCIAL MEDICINE
Part 2:
FILL IN THE BLANKS
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- The candle of Pasteur Chamberland filter is made of _______________ and that of Berkefeld filter is made of _______________
ANS: porcelain , kieselgurh (infusrial earth) - The bactericidal action of Ktadyn filter is due to the _______________ ation of silver ions
ANS: oligodynamic - The UV rays disinfection of water involves the exposure of a fim of water about _______________ mm thick.
ANS: 120 - The most effective and cheapest way of disinfecting wells is by _______________ and should not use _______________
ANS: bleaching powder, potassium permanganate - Chlorine demand of well water can be estimated by using _______________
ANS: Horrock’s apparatus - The double pot method of chlorination is a method devised by _______________
ANS: National Environmental Engineering Research Institute, Nagpur - Water with turbidity of more than _______________ nephlometric turbidity units (NTU) is usually noticeable to the naked eyes
ANS: 4 - The WHO (2011) guideline value for colour of drinking water is _______________
ANS: 15 true colour units ( TCU) - The standard prescribed level for chloride in drinking water is …………….. mg/L and maximum permissible level is _______________ mg/L
ANS: 200, 600 - Levels of ammonia in ground and surface water is _______________ mg/L and that in anaerobic ground water is _______________ mg/L
ANS: 0.2 , 3 - Acceptable pH of drinking water is between _______________
ANS: 6.5 and 8.5 - The taste and odour threshold of hydrogen sulphide in water are estimated to be between _______________
ANS: 0.05-0.1 mg/L - Water with a total dissolved solids (TDS) below _______________ mg/L is usually acceptable and that with a TDS level below _______________ mg/L is considered to be good
ANS: 1000, 600 - The prsence of faecal _______________ indicate recent faecal pollution of water
ANS: Streptococci - Disinfection with 0.5mg/L of free chlorine residual after contact period of _______________ minutes at a pH of _______________ is sufficient to inactivate virus
ANS: 30, 8 - Cadmium accumulates primarily in the _______________
ANS: kidney - _______________ is the main target organ for inorganic mercury and that for methyl mercury is ______________
ANS: kidney, central nervous system - The upper limit of cocentration of carbon tetrachloride in water is _______________
ANS: 2 microgram/L - The upper limit of concentration of DDT in water is _______________
ANS: 2 microgram/L - High levels of fluoride causes _______________ of dental enamel
ANS: mottling - High nitrate content of water is associated with _______________
ANS: methaemoglobinemia - _______________ is an estimate of the amount of a substance in food or drinking water that can be ingested daily over a lifetime without appreciable health risk
ANS: tolerable daily intake (TDI) - _______________ is the highest dose or concentration of a chemical in a single study, found by experiment that causes no detectable adverse health effect
ANS: NOAEL ( no-observed-adverse-effect level) - _______________ is the lowest observed dose or concentration of a substance at which there is detectable adverse health effect
ANS: LOAEL (lowest-observed-adverse-effect level) - The effects of radiation exposure are called_______________ if the become manifest in the exposed individual, and _______________ if they affect the descendants.
ANS: somatic, hereditary - _______________is the most important delayed somatic effect of radiation
ANS: Malignant disease - The proposded guide line value for gross alpha activity is _______________
ANS: 0.5 Bq/L - The proposed guide line value for gross beta activity is _______________
ANS: 1 Bq/L - _______________test is based on estimating the most probable number (MPN) of coliform organisms in 100ml of water
ANS: Mutiple tube method - Multiple tube method is carried out using _______________broth with _______________as indicator
ANS: McConkey’s Lactose Bile Salt Broth, Bromocresol purpleMut - Multiple tube method will give the result as _______________
ANS: Presumptive coliform count - For confirmation of the coliform _______________broth is used
ANS: Brilliant green bile broth - For confirmation of the presence of coliform organisms the broths are incubated at _______________degree and for E coli at _______________degree
ANS: 37, 44 - In membrane filtration technique for testing the presence of coliform organisms _______________membranes are used
ANS: cellulose ester - Colony counts on nutrient agar at _______________degree and _______________degree are used in bacteriological examination of water
ANS: 37, 22 - The recommended plate count for estimating the bacterial purity of disinfected water is _______________after 2 days at 37 degee and _______________after 3 days at 22 degree.
ANS: 0, 20 - _______________organisms are an index of pollution.
ANS: Plankton - _______________is dedfined as the soap destroying power of water.
ANS: Hardness - The hardness in water is caused mainly by the bicarbonates and sulphates of _______________and _______________
ANS: Calcium, Magnesium - _______________hardness is due to the presence of calcium and magnesium bicarbonates
ANS: Temporary - _______________hardness is due to the prsence of calcioum and magnesium sulphates, chlorides and nitrates
ANS: Permanent - One milli-equivalents per ltre of hardness producing ion is equal to _______________mg/L of CaCO3
ANS: 50 - Level of hardness in soft water is _______________mg/L
ANS: < 50 - Level of hardness of moderately hard water is _______________mg/L
ANS: 50-150 - Level of hardness in hard water is _______________mg/L
ANS: 150-300 - Level of hardness in very hard water is _______________mg/L
ANS: > 300 - Boiling, addition of lime , addition of sodium carbonate and permutit process are methods to remove _______________hardness
ANS: temporary - The methods to remove permanent hardness are _______________and _______________
ANS: addition of sodium carbonate, base exchange process - In Clark’s method of softening water _______________is used
ANS: quick lime - _______________is a complex compound of sodium, aluminium and silica used in permutit process
ANS: Sodium permutit - _______________and _______________methods removes both temporary and permanent hardness.
ANS: Addition of sodium carbonate, Permutit process - _______________has the property of exchanging sodium cation for the calcium and magnesium ions in the water
ANS: Sodium permutit - Epidermophyton and Trichophyton species produce _______________
ANS: Athlete,s foot - _______________virus is the inciting agent of plantar warts
ANS: Papilloma - Water of zero hardness has _______________action
ANS: corrosive - The recommended maximum limit of concentration of Arsenic in drinking water is _______________mg/L
ANS: 0.01 - The recommended maximum limit of concentration of Antimony in drinking water is _______________mg/L
ANS: 0.02 - The recommended maximum limit of concentration of Cadmium in drinking water is _______________mg/L
ANS: 0.003 - The recommended maximum limit of concentration of Fluoride in drinking water is _______________mg/L
ANS: 1.5 - The recommended maximum limit of concentration of Lead in drinking water is _______________mg/L
ANS: 0.01 - The recommended maximum limit of concentration of Mangenese in drinking water is _______________mg/L
ANS: 0.4 - The recommended maximum limit of concentration of Mercury (total) in drinking water is _______________mg/L
ANS: 0.006 - The recommended maximum limit of concentration of Nitrate in drinking water is _______________mg/L
ANS: 50 - The recommended maximum limit of concentration of Nitrite in drinking water is _______________mg/L
ANS: 3 - The recommended maximum limit of concentration of Selenium in drinking water is _______________mg/L
ANS: 0.04
REFERENCE:
PARK’S TEXTBOOK OF PREVENTIVE AND SOCIAL MEDICINE
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