L5 And 6

Question 1

What are the three main parameters used to assess water quality?

Answer 1

Physical, Chemical, and Biological parameters

Question 2

List some physical parameters of water.

Answer 2

• Temperature
• Colour
• Odour
• Total suspended solids (TSS)
• Total dissolved solids (TDS)
• Taste
• Turbidity
• pH range

Question 3

What does TSS stand for in water quality assessment?

Answer 3

Total Suspended Solids

Question 4

What does TDS stand for in water quality assessment?

Answer 4

Total Dissolved Solids

Question 5

Give examples of chemical parameters in water quality.

Answer 5

• Dissolved Oxygen (DO)
• BOD (Biochemical Oxygen Demand)
• COD (Chemical Oxygen Demand)
• Chloride (as Cl)
• Alkalinity (as CaCO3)
• Nitrate (as NO3)
• Nitrite (as NO2)
• Fluoride (as F)
• Total phosphates (as PO4)
• Total Hardness (as CaCO3)
• Total iron (as Fe)
• Sulphate (as SO4)
• Metals
• Pesticides
• Surfactants

Question 6

What are some biological parameters used in water quality assessment?

Answer 6

• Escherichia coli (E. coli)
• Total Coliform bacteria
• Fecal Coliform bacteria

Question 7

What can cause reddish color in water?

Answer 7

Iron-oxides

Question 8

What is the Sri Lankan Standard (SLS) for Iron (Fe) in water?

Answer 8

0.3 mg/L

Question 9

What is turbidity?

Answer 9

A measure of water clarity

Question 10

What are the effects of turbidity on water?

Answer 10

• Diffuses sunlight
• Absorbs heat
• Clogs fish gills
• Reduces light for photosynthesis
• Increases water treatment costs

Question 11

What device is used to measure turbidity?

Answer 11

Turbidimeter

Question 12

What is the WHO standard for turbidity in water?

Answer 12

5 NTU

Question 13

What is the pH scale range?

Answer 13

0 to 14

Question 14

What is considered neutral pH?

Answer 14

pH 7

Question 15

What happens if pH < 5.5 in water?

Answer 15

The water may be too acidic for aquatic organisms to survive

Question 16

How is pH measured?

Answer 16

Using a pH-meter or pH paper

Question 17

What is the normal pH range for surface water systems?

Answer 17

6.5 to 8.5

Question 18

What is conductivity in water?

Answer 18

The measure of water’s ability to conduct an electric current

Question 19

How is conductivity measured?

Answer 19

Using a Conductivity meter in microsiemens per centimeter (μS/cm)

Question 20

What is total hardness in water?

Answer 20

The sum of Calcium hardness and Magnesium hardness

Question 21

What are the two types of water hardness?

Answer 21

• Carbonate hardness (Temporary Hardness)
• Non-carbonate hardness (Permanent Hardness)

Question 22

What is the Sri Lankan Standard (SLS) for total hardness in water?

Answer 22

250 mg/L as CaCO3

Question 23

What are nontoxic metals commonly found in water?

Answer 23

• Sodium
• Iron
• Calcium
• Manganese
• Aluminum
• Copper
• Zinc

Question 24

What are some toxic metals that may be found in water?

Answer 24

• Arsenic
• Barium
• Cadmium
• Chromium
• Lead
• Mercury
• Silver

Question 25

What is bioaccumulation?

Answer 25

The increase in concentration of pollutants in an organism over time

Question 26

What is biomagnification?

Answer 26

The increase in concentration of a substance in a food chain

Question 27

What disease was caused by mercury poisoning in Japan?

Answer 27

Minamata disease

Question 28

What is the Sri Lankan Standard (SLS) for fluoride in drinking water?

Answer 28

< 1.0 mg/L

Question 29

What health issues can excessive fluoride intake cause?

Answer 29

Dental fluorosis and bone fluorosis