Microbes and Water Part 1 Flashcards
What is water pollution?
Biological changes harmful to water quality
What is water potability?
Tells you whether or not the water is safe to drink
What can you expect to find in unpolluted water?
Low organic nutrients therefore low numbers of microbes
How can water be polluted?
- Sewage
- Agricultural runoff (phosphates)
- Industrial runoff (actual chemicals)
What can you expect to see in polluted water?
High in organic matter and coliform and noncoliform bacteria
What are accumulated phosphates?
They are from agricultural or industrial runoff and cause algal blooms
What do algal blooms do?
Supply nutrients to other microbes which use of the oxygen in the water
-aquatic and plant life die and accumulate on the bottom where anaerobic bacteria decompose the material further using the available oxygen
What are the 3 types of water pollution?
Physical: sand, soil, cyanobacterias blooms
Chemical: inorganic, organic waste
Biological: Microorganisms from anthropogenic sources
What is the BOD?
Biological Oxygen Demand of water is the amount of water microbes need to decompose organic matter
-used to describe the pollution status of waters
What happens when a nutrient enters a water body as a pollutant?
It provides nutrition to microbes and in using that nutrient they will use oxygen
What happens when a body of water has a high BOD?
It is able to support rapid microbial growth and can lose oxygen quickly. possible causing a fish kill
What is the definition of eutrophic?
Waters that are overloaded with nutrients
-can cause water discolouriton
What types of diseases can be transmitted by water?
- Typhoid fever
- Cholera
- Shigllosis
- Legionnaires disease
What is Erysipeloid?
infection caused by the Marine pathogen Erysipelothrix rhusiopathiiae
What does mycobacterium marinum cause?
Lesion (granuloma) at the site of a wound called Fish Handlers Disease
What can Vibrio vulnificus cause?
Intestinal illness if raw oysters are consumed
Wound infections involving gangrene and necrotizing fasciitis
What viruses can water transmit?
Hep A
Rotavirus
Gastroenteritis
Polio
What eukaryotic organisms can water transmit?
Entamoeba histolytica
Giardia lamblia
Crytosporidium
What aree dinoflagellates able to transmit through water?
A toxin which causes ciguatera poisoning in humans
What is used to assess water pollution?
Fecal coliforms
What is a fecal coliform?
rod shaped gram - bacteria normally resident in our large intestines or the intestines of animals such as farm cattle pigs etc.
What is the usual organism that indicates water pollution?
E coli, usually indicated fecal contamination of municipal drinking water supplies
Where do coliforms not grow?
Streams
Lakes
Spill sites
What is another example of a bacteria that is also in the coliform group?
Klebsiella
Do all coliforms cause disease?
Many coliforms are NOT disease causing and are a normal component of our gut flora, and are commonly found in soils as well
What is a Total Plate Count?
Microbiological tests performed to identify which bacteria is present and how many are there per mL
What is a membrane filter?
used to pass large volumes of water through to retain bacteria from the water sample.
-Filter is then placed on a pad of nutrient medium so that colonies grow and can be counted
What are colour indicator tests used for?
Special nutrient broth solutions are inoculated with samples and specific colour reactions which indicate the presence of coliforms
-Can usually tell the kind of bacteria that is present
What are municipal water supplies treated with?
Flocculating agents
-Alum
What is the purpose of alum?
Binds with suspended matter and forms flocs that sink and can then be removed and then the water is filtered through sand beds
What is the 3 steps for water purification?
Sedimentation: Removes large objects and particles through flocculation
Filtration: removes microorganisms by passing water through a layer of sand, gravel and microbe biofilm
Chlorination: involves adding chlorine gas to kill remaining organisms
What is chlorine used in water purification?
To kill microbes.
In what form is chlorine injected into the water?
In gas form
Why do we have to monitor the chlorine process carefully?
Chlorine will bind with organic matter in the input water
-enough has to be added to bing all organic matter and still have enough free chlorine leftover to kill bacteria (but only just enough)
How is the chlorine dosed?
Needs to be enough to kill microbes both in the treatment plant and in the piping used to distribute the water to the end user
What should happen to the Chlorine when it gets to the end user?
There should be virtually no free chlorine present
