1. : Which of the following is a primary parameter in water quality monitoring?
(A) Dissolved Oxygen (DO)
(B) Air pressure
(C) Soil density
(D) Wind velocity
2. : The instrument commonly used to measure pH of water is:
(A) Turbidimeter
(B) pH meter
(C) Secchi disk
(D) Anemometer
3. : A Secchi disk is used to measure:
(A) Water temperature
(B) Light penetration / water transparency
(C) Salinity
(D) Dissolved solids
4. : Which parameter is an indicator of organic pollution in water?
(A) BOD (Biochemical Oxygen Demand)
(B) Wind speed
(C) Rainfall
(D) Soil compaction
5. : COD (Chemical Oxygen Demand) measures:
(A) Amount of organic matter chemically oxidizable
(B) Amount of dissolved salts
(C) Bacterial count in water
(D) Water temperature
6. : Which water quality parameter is most critical for aquatic life survival?
(A) Dissolved Oxygen
(B) Soil density
(C) Wind speed
(D) Light wavelength
7. : High levels of nitrates in drinking water can cause:
(A) Asthma
(B) Blue baby syndrome (methemoglobinemia)
(C) Diabetes
(D) Arthritis
8. : Which unit is commonly used for measuring turbidity?
(A) NTU (Nephelometric Turbidity Unit)
(B) Lux
(C) ppm
(D) Joule
9. : Which instrument measures electrical conductivity of water?
(A) Conductivity meter
(B) Barometer
(C) Secchi disk
(D) Clinometer
10. : High BOD levels in water indicate:
(A) Good water quality
(B) High organic pollution
(C) High oxygen availability
(D) Absence of life
11. : TDS (Total Dissolved Solids) in water is measured in:
(A) mg/L
(B) Lux
(C) °C
(D) Pascal
12. : The parameter that measures salt concentration in water is:
(A) Salinity
(B) Turbidity
(C) BOD
(D) Conductivity
13. : Which test is used to detect fecal contamination in water?
(A) Coliform test
(B) Turbidity test
(C) DO test
(D) Secchi disk reading
14. : Which bacteria is used as an indicator of water pollution?
(A) Salmonella
(B) Escherichia coli (E. coli)
(C) Vibrio cholerae
(D) Bacillus subtilis
15. : Which gas is most important in determining water quality for fish?
(A) Oxygen
(B) Nitrogen
(C) Carbon dioxide
(D) Methane
16. : Alkalinity in water refers to:
(A) Ability to neutralize acids
(B) Presence of organic matter
(C) Amount of oxygen dissolved
(D) Water temperature
17. : The ideal pH range of drinking water is:
(A) 2–3
(B) 4–5
(C) 6.5–8.5
(D) 9–11
18. : Which heavy metal is commonly tested in water due to its toxicity?
(A) Mercury
(B) Calcium
(C) Potassium
(D) Magnesium
19. : DO (Dissolved Oxygen) is measured in:
(A) ppm or mg/L
(B) °C
(C) NTU
(D) Lux
20. : Which instrument is used to measure turbidity?
(A) Turbidimeter
(B) Hygrometer
(C) Rain gauge
(D) Lux meter
21. : Eutrophication of water bodies is mainly caused by:
(A) Excess nutrients (nitrates & phosphates)
(B) Lack of rainfall
(C) Acid rain
(D) Low temperature
22. : Which method is used to measure chlorophyll concentration in water?
(A) Spectrophotometry
(B) Secchi disk
(C) Turbidimeter
(D) Conductivity meter
23. : Which gas increases in polluted water due to decomposition of organic matter?
(A) CO₂
(B) O₂
(C) CH₄
(D) Both (A) and (C)
24. : Which of the following is a biological parameter of water quality?
(A) BOD
(B) COD
(C) Coliform count
(D) TDS
25. : High turbidity in water affects:
(A) Light penetration and photosynthesis
(B) Soil fertility
(C) Air humidity
(D) Oxygen in atmosphere
26. : Which index integrates multiple water parameters to give overall quality?
(A) WQI (Water Quality Index)
(B) BOD Index
(C) COD Index
(D) DO Index
27. : Which toxic element in groundwater is associated with skin cancer?
(A) Fluoride
(B) Arsenic
(C) Calcium
(D) Potassium
28. : The permissible limit of fluoride in drinking water is:
(A) 0.5–1.5 mg/L
(B) 5–10 mg/L
(C) 15–20 mg/L
(D) 25–30 mg/L
29. : Thermal pollution of water is mainly caused by:
(A) Industrial effluents
(B) Power plants discharging hot water
(C) Rainfall changes
(D) Excess nitrates
30. : Which water quality parameter indicates hardness?
(A) Calcium and Magnesium concentration
(B) Sodium chloride content
(C) Oxygen saturation
(D) Turbidity
31. : Which is a physical parameter of water quality?
(A) pH
(B) Turbidity
(C) DO
(D) Coliform count
32. : Eutrophication often leads to:
(A) Algal blooms
(B) Oxygen depletion
(C) Fish kills
(D) All of the above
33. : Which method is used to measure DO (Dissolved Oxygen) in water?
(A) Winkler method
(B) Turbidimeter method
(C) Secchi disk method
(D) BOD test
34. : Excess fluoride in water can lead to:
(A) Dental fluorosis
(B) Asthma
(C) Heart disease
(D) Skin rash
35. : Which form of nitrogen indicates sewage pollution in water?
(A) Ammonia nitrogen
(B) Nitrate nitrogen
(C) Nitrite nitrogen
(D) All of the above
36. : Which water quality parameter is crucial for photosynthesis in aquatic plants?
(A) Light penetration
(B) CO₂ availability
(C) Nutrient levels
(D) All of the above
37. : The process of water becoming enriched with nutrients and leading to oxygen depletion is called:
(A) Eutrophication
(B) Biomagnification
(C) Mineralization
(D) Sedimentation
38. : Hardness of water is expressed in:
(A) mg/L of CaCO₃
(B) ppm of O₂
(C) NTU
(D) Lux
39. : Which of the following is used to measure salinity in seawater?
(A) Refractometer
(B) Secchi disk
(C) Turbidimeter
(D) GPS
40. : The permissible limit of arsenic in drinking water (WHO guideline) is:
(A) 0.01 mg/L
(B) 0.1 mg/L
(C) 1 mg/L
(D) 5 mg/L
41. : High chloride concentration in water usually indicates:
(A) Industrial or sewage pollution
(B) Photosynthetic activity
(C) Thermal stratification
(D) Oxygen supersaturation
42. : The main source of nitrate pollution in water is:
(A) Fertilizer runoff
(B) Volcanic eruptions
(C) Soil erosion
(D) Thermal discharge
43. : Which metal in water is associated with Itai-Itai disease?
(A) Cadmium
(B) Arsenic
(C) Lead
(D) Mercury
44. : Dissolved Oxygen (DO) levels below 4 mg/L generally indicate:
(A) Healthy water body
(B) Poor water quality for aquatic organisms
(C) High productivity
(D) Low nutrient load
45. : Which instrument is commonly used for on-site multiparameter water quality testing?
(A) Portable water quality probe
(B) Hygrometer
(C) Secchi disk
(D) Barometer
46. : Total coliforms in water include:
(A) Only pathogenic bacteria
(B) Both pathogenic and non-pathogenic bacteria
(C) Only algae
(D) Only protozoa
47. : Which parameter is NOT a biological indicator of water quality?
(A) Phytoplankton
(B) Zooplankton
(C) Fish species diversity
(D) TDS
48. : Groundwater contamination by arsenic is most common in:
(A) South Asia (Bangladesh, India)
(B) North America
(C) Australia
(D) Antarctica
49. : Which method is used to determine COD (Chemical Oxygen Demand)?
(A) Dichromate reflux method
(B) Winkler method
(C) Secchi disk method
(D) Spectrophotometry only
50. : The ultimate goal of water quality monitoring is:
(A) To ensure safe drinking water and healthy ecosystems
(B) To study wind velocity
(C) To improve soil density
(D) To measure only pH levels