Bacterial Isolation
Which type of bacterial is Gram-negative, and what colour indicates this?
E. coli, pink/red colour
Chemical compounds that combine to be more toxic than either individual compound are described as?
Synergistic
What is a risk assessment?
A process that evaluates the potential risks of a particular outcome because of a particular event.
Which test organism was used for Lab 8 and why? Give three reasons.
Daphnia magna: easily grown, inexpensive and highly sensitive to changes in water chemistry
Which scientist conclusively established that a particular germ could cause a specific disease?
Robert Koch
What is the name of the culture media most frequently used for bacterial colony growth and where does it come from?
Agar, and it originates from red algae
What is the dose-response relationship, and who invented it?
The relationship between exposure and health effect, that can be established by measuring the response relative to an increasing dose
Paracelsus
What is the difference between a hazard and a risk?
Hazard = anything that can cause harm
Risk = the likelihood or probability of a hazard causing harm
What are three types of bacteria that can be analyzed using the IDEXX method, and which types fluoresced?
Total coliform, E. coli and Enterococcus
Total coliform = yellow, E. coli and Enterococcus = fluorescent blue
What is the name of the Niagara Falls NY neighbourhood that was evacuated in the 1970s and what was the source of contamination?
Love Canal, contamination came from a canal that was filled with >22,000 tons of toxic chemicals
What is the difference between selective and differential growth media? Give an example of a selective and differential growth media.
Selective = promotes growth of specific bacteria and inhibits others
Differential = can distinguish between different types of bacteria based on biological characteristics
Example: mColiblue24
Which two chemical properties can be used to determine if a contaminant will be found in water or sediment? List one persistent chemical that is found mainly in sediment.
Aqueous solubility and Kow
Examples: PCBs, DDT, methylmercury
What are three types of risk assessments?
Human health RA, ecological RA, environmental RA
What are three different techniques that can be used for bacterial isolation?
1) plate spreading, 2) plate streaking, 3) plate pouring
Jennifer Volpato's case study focussed on which property in St. Catharines, and which contaminant?
The Meridian Centre and methane
What are four key requirements for growth when culturing microorganisms?
Food, pH, time, temperature, oxygen, moisture
How is contaminant persistence related to half-life, bioaccumulation and biomagnification?
Highly persistent contaminants typically have longer half-lives, therefore longer exposure to biota and higher bioaccumulation/biomagnification
What are the four steps in the risk assessment process?
1) Hazard identification, 2) Dose-response assessment, 3) Exposure assessment, 4) Risk characterization
What is a bioassay and what is the LC50? What information goes on an LC50 graph?
Bioassay = methods that use living organisms to determine the potential toxicity of substances
LC50 = concentration causing lethality in 50% of the test organisms within a given time period
LC50 graph = % mortality on y-axis vs. toxin conc. on x-axis
What are four factors that affect toxicity?
1) type of toxin, 2) dose, 3) duration, 4) exposure route
What are the five I's of bacterial culturing?
Inoculate, Isolate, Incubate, Inspect and Identify
What are the four routes of exposure and the four categories of adverse effects?
Ingestion, inhalation, injection, absorption
Carcinogenic, mutagenic, teratogenic, physiologic
What are four considerations in an exposure assessment?
1) Probability of exposure, 2) magnitude of exposure, 3) route of exposure, and 4) population affected
Aseptic = free from contamination caused by harmful bacteria, viruses, or other microorganisms
4 techniques: using flame sterilization, ethanol spray, nitrile gloves, surgical masks, use parafilm/cover plates, do not touch inside of apparatus
Name one environmental disaster (other than Love Canal or Chernobyl) and describe the toxin(s) and effects.
Sadly there are many to choose from here...