(Lab 3) Water Quality Testing

Question 1

What does water quality testing specifically look for? What does that tell us about the quality of the water?

Answer 1

Looks for fecal coliforms, bacteria from human waste from sewage spills/leaks

Tells us if the water is safe for recreational use, not consumption

Question 2

What different intestinal pathogens would we look for in water quality testing?

Answer 2

Salmonella typhi - typhoid fever

Vibrio cholerae - cholera

Shigella flexneri - dysentery

Multiple protozoans, helminths, and viruses

Question 3

What is a coliform? Why do they matter for water quality testing?

Answer 3

Gram-negative rod that ferments lactose (+AG)
- indicative of fecal matter

Question 4

What is the indicator species used in water quality testing? Why is it our indicator?

Answer 4

E. coli
- mostly found in human waste. Sometimes animal waste

If E. coli is present, fecal coliforms may be present as well

Question 5

What are the stages of Water Quality Testing?

Answer 5

1. Presumptive Test
2. Confirmed test
3. Completed test

Question 6

What is performed in the presumptive test? Why do we perform presumptive tests?

Answer 6

Series of lactose fermentation tubes

It is a screening test - quick, easy, cheap

Question 7

What does the lactose fermentation tube estimate in water quality testing?

Answer 7

Most Probable Number (MPN) the concentration of coliform organisms

Question 8

When is MPN important?

Answer 8

When fecal coliform is determined

Question 9

What is performed in the confirmed test?

Answer 9

EMB agar plate

Question 10

What are the possible results of an EMB plate?

Answer 10