Microbiology Of Water

Question 0

How many coliforms allowed in:

a) drinking water
b) recreational water

Answer 0

a) none!

b) up to 200 faecal coliform per 100ml (found in coastal zones a lot)

Question 1

What is a coliform?

Answer 1

A non-sporing bacteria found in the faeces of warm-blooded animals

Question 2

Sources of faecal pollution:

Answer 2

1. Human STWs
2. Septic tanks
3. Concentrated animal feeding ops (CAFOs)
4. Pastured animals moo shitting in or near rivers
5. Migratory birds (really?)

Question 3

Can you name two types of protozoan? (Begin with G)

Answer 3

Giardiasis and Gryptosporidious (sporadically gripped)

= resistant to chlorine but can be filtered

Question 4

Targeting faecal pollution - FIOs to monitor quality

What do you use to test whether f coliforms come from human or animals?

Answer 4

Faecal Streptococci

Question 5

What are the faecal coliform to faecal streptococci ratios for a human, duck and cow?

Answer 5

Human = 4.4
Duck = 0.6
Cow = 0.2

Question 6

“Host specific” strains of E. Coli can be distinguished using what and what?

Answer 6

Their phenotype and genotype

This is the bacterial source tracking method

Can also do a PCR test based on the target gene in E. coli

Question 7

Shoal creek bacteria source tracking case study

Answer 7

• 90% of pasture land grazed by 300,000 cattle
• poultry litter spread (v high in nitrogen, up to 45%)
• 21km of shoal creek designated as impaired due to high contamination

Results form test found:

• cattle are main contributors especially in summer when out to pasture
• poultry waste also significant pollutant
• multiple host source of faeces

Question 8

IDEXX QUANTI TRAY METHOD for FIO analysis

Answer 8

• incubate samples at 35 and 45 degrees in tray and add coliform solution to sample and mix for 24 hrs
• enumeration step: use DEXX quanti tray 2000 most probable number

Question 9

Scoping FIOs in the Wensum Catchment

Answer 9

The location of STW influences f coli counts, but distance from STW does not have significant impact
Presence of diffuse livestock poll has impact too
Total no. coli not strongly associated with STWs
But are with high flow events x10 increase in e. Coli