Bacteria and Water Quality

1
Bacteria and Water Quality

• Envr 1402

2
Bacterias Impacts on Water Quality

• Transmission of disease
• Water clarity
• Odor
• Taste
• Toxicity
• Can you think of any more?

3
Bacteria Facts

• Bacteria are single cell protists
• Their nucleus is not enclosed in a true nuclear
  membrane
• Bacteria are normally present in water
• The concentration of bacteria is significant with
  respect to potential disease transmission

4
Coliforms

• A coliform is a group of bacteria, which includes
  Escherichia coli (E. coli), used in water
  testing.
• The concentration of coliform bacteria are most
  often reported as the most probable number per
  100mL (MPN)
• MPN is determined by the number of positive tests
  for lactose-fermenting bacteria

5
E. Coli Facts

• E. coli ferments lactose.
• E. coli is naturally found in the human
  intestines and human feces.
• E. coli is used to determine water pollution
  because it is found in human feces and therefore
  indicates the presence of fecal matter in the
  water.

6
Groundwater Contamination

• Groundwater contamination commonly results from
  human activities.
• Industrial waste water
• Impoundments
• Sanitary landfills
• Septic tanks
• Chemicals/pesticides
• Can you think of anymore?

7
Counting Colonies in Your Water Sample

• For your water sample you will want to note the
  different types of colonies.
• Assume you had 100mL of each water sample and you
  used 0.5mL of it to streak your plate.
• Use the following formula
• Colonies per 100mL of colonies x 100mL
• 
  0.5mL

8
Counting Colonies Bleach/E. coli

• If there are too many colonies to count, write
  TNTC (too numerous to count).
• Use a marker/wax pencil to draw four equal
  sections on your plate. Pretend you are cutting
  a pie in 4 equal parts.
• Count the colonies in one quarter and then
  multiply that number by 4 to approximate the
  number of colonies on your whole plate.
• Note which concentration of bleach was most
  effective in killing the E. coli and which one
  was the least effective.