HSCI 204 MODULE 8 EXAM QUESTIONS ANSWERED CORRECTLY LATEST UPDATE 2026
Why is water essential for life - Answers Humans need about 2.5 liters per day and the body is largely
composed of water making it critical for survival and physiological function.
Why is chlorination important in public health - Answers Chlorination has greatly reduced diseases
such as cholera and typhoid making it one of the most important public health interventions.
List vulnerable populations for waterborne disease - Answers Children elderly and
immunocompromised individuals are most vulnerable.
What percentage of Earth's water is accessible for humans - Answers Only about 0.01 percent of
global water is accessible for human use.
Define hydrological cycle - Answers The hydrological cycle is the continuous movement of water
through evaporation condensation precipitation runoff and infiltration.
List steps of hydrological cycle - Answers Evaporation condensation precipitation runoff and
infiltration.
Define groundwater - Answers Groundwater is water stored underground in aquifers.
Define surface water - Answers Surface water includes lakes rivers and reservoirs.
Define water scarcity - Answers Water scarcity is when availability is less than 1000 cubic meters per
person per year.
Define water stress - Answers Water stress occurs when water availability is between 1000 and 1700
cubic meters per person per year.
List four main stages of water treatment - Answers Coagulation sedimentation filtration and
disinfection.
Explain coagulation - Answers Coagulation involves adding chemicals like aluminum sulfate to clump
particles together.
Explain sedimentation - Answers Sedimentation allows heavy particles to settle out of the water.
Explain filtration - Answers Filtration uses sand and charcoal to remove smaller impurities.
Explain disinfection - Answers Disinfection uses chlorine or other methods to kill pathogens.
Why is disinfection critical - Answers It removes disease causing microorganisms preventing
waterborne illness.
Which organism is resistant to chlorine - Answers Cryptosporidium is resistant to chlorine
disinfection.
Define chlorine residual - Answers Chlorine residual is the small amount of chlorine left in water after
treatment.
Why is chlorine residual beneficial - Answers It continues to disinfect water as it travels through pipes
preventing contamination.
Why can chlorine residual be harmful - Answers It can cause taste and odor issues and form harmful
disinfection byproducts.
Define fluoridation - Answers Fluoridation is the addition of fluoride to water to prevent tooth decay.
What is optimal fluoride level - Answers Optimal fluoride levels are 0.7 to 1.2 ppm.
List sources of drinking water contamination - Answers Contamination can be natural such as arsenic
or human made such as fertilizers sewage and industrial chemicals.
List categories of waterborne disease - Answers Protozoa bacteria viruses and chemicals.
Describe Cryptosporidium - Answers Cryptosporidium is a chlorine resistant parasite causing diarrhea
and severe illness especially in immunocompromised individuals.
Describe 1993 Milwaukee outbreak - Answers It was a Cryptosporidium outbreak causing over
400000 cases of illness.
Describe E coli infection - Answers E coli can cause bloody diarrhea and severe illness.
Describe cholera - Answers Cholera is caused by Vibrio cholerae and leads to severe dehydration.
Define foodborne illness - Answers Foodborne illness occurs when contaminated food is ingested
causing disease.
List categories of food hazards - Answers Biological chemical and physical hazards.
Define food infection - Answers Food infection occurs when live bacteria are ingested and multiply in
the body.
Define food intoxication - Answers Food intoxication occurs when toxins already present in food are
consumed.
Give example of food infection - Answers Salmonella is an example of food infection.
Why is water essential for life - Answers Humans need about 2.5 liters per day and the body is largely
composed of water making it critical for survival and physiological function.
Why is chlorination important in public health - Answers Chlorination has greatly reduced diseases
such as cholera and typhoid making it one of the most important public health interventions.
List vulnerable populations for waterborne disease - Answers Children elderly and
immunocompromised individuals are most vulnerable.
What percentage of Earth's water is accessible for humans - Answers Only about 0.01 percent of
global water is accessible for human use.
Define hydrological cycle - Answers The hydrological cycle is the continuous movement of water
through evaporation condensation precipitation runoff and infiltration.
List steps of hydrological cycle - Answers Evaporation condensation precipitation runoff and
infiltration.
Define groundwater - Answers Groundwater is water stored underground in aquifers.
Define surface water - Answers Surface water includes lakes rivers and reservoirs.
Define water scarcity - Answers Water scarcity is when availability is less than 1000 cubic meters per
person per year.
Define water stress - Answers Water stress occurs when water availability is between 1000 and 1700
cubic meters per person per year.
List four main stages of water treatment - Answers Coagulation sedimentation filtration and
disinfection.
Explain coagulation - Answers Coagulation involves adding chemicals like aluminum sulfate to clump
particles together.
Explain sedimentation - Answers Sedimentation allows heavy particles to settle out of the water.
Explain filtration - Answers Filtration uses sand and charcoal to remove smaller impurities.
Explain disinfection - Answers Disinfection uses chlorine or other methods to kill pathogens.
Why is disinfection critical - Answers It removes disease causing microorganisms preventing
waterborne illness.
Which organism is resistant to chlorine - Answers Cryptosporidium is resistant to chlorine
disinfection.
Define chlorine residual - Answers Chlorine residual is the small amount of chlorine left in water after
treatment.
Why is chlorine residual beneficial - Answers It continues to disinfect water as it travels through pipes
preventing contamination.
Why can chlorine residual be harmful - Answers It can cause taste and odor issues and form harmful
disinfection byproducts.
Define fluoridation - Answers Fluoridation is the addition of fluoride to water to prevent tooth decay.
What is optimal fluoride level - Answers Optimal fluoride levels are 0.7 to 1.2 ppm.
List sources of drinking water contamination - Answers Contamination can be natural such as arsenic
or human made such as fertilizers sewage and industrial chemicals.
List categories of waterborne disease - Answers Protozoa bacteria viruses and chemicals.
Describe Cryptosporidium - Answers Cryptosporidium is a chlorine resistant parasite causing diarrhea
and severe illness especially in immunocompromised individuals.
Describe 1993 Milwaukee outbreak - Answers It was a Cryptosporidium outbreak causing over
400000 cases of illness.
Describe E coli infection - Answers E coli can cause bloody diarrhea and severe illness.
Describe cholera - Answers Cholera is caused by Vibrio cholerae and leads to severe dehydration.
Define foodborne illness - Answers Foodborne illness occurs when contaminated food is ingested
causing disease.
List categories of food hazards - Answers Biological chemical and physical hazards.
Define food infection - Answers Food infection occurs when live bacteria are ingested and multiply in
the body.
Define food intoxication - Answers Food intoxication occurs when toxins already present in food are
consumed.
Give example of food infection - Answers Salmonella is an example of food infection.
