Lecture 22

Question 1

What are some RHD genes?

Answer 1

Ring Hydroxylating Dioxygenases
nahA

Question 2

What are some cons of using biodegradation genes to determine if MNA is viable?

Answer 2

• Primer bias
• no information on the species responsible or which organisms harbour the gene
• may not be feasible to monitor multiple genes in every sample

Question 3

What is a limitation of the push pull test in determining rates of anaerobic biodegradation?

Answer 3

no information about species carrying out the metabolism nor under what specific condition.

Question 4

What are two ways of performing the single well Push-Pull test?

Answer 4

• Reactants + tracer
• d-labelled hydrocarbons + tracer

Question 5

What are some limitations of CSIA?

Answer 5

Compound Specific Isotope Analysis

• expensive equipment.
• Substantial biodegradation needed to observe signal.
• since ¹²C is more readily used than ¹³C the ratio will change as biodegradation occurs.

Question 6

What is a limitation of bioaugmentation? How can this limitation be minimized?

Answer 6

• Added microbes do not always complete will with indigenous populations. To avoid this, it is best to culture cells with biodegradation ability from the given environment of concern and then add back.

Question 7

What is a local example of bioremediation using biopiles?

Answer 7

wood-preserving facility in Cochrane lead to surrounding area being contaminated with creosote. The soil was excavated and put into biopiles where microbes and fertilizers were added to piles to assist in aeration

Question 8

what is the difference between bioventing and biosparging?

Answer 8

Bioventing is adding air to the unsaturaded zone, while biosparging is adding air to groundwater (below the watertable)

Question 9

What is a limitation of biosparging/ bioventing?

Answer 9

• can’t always get concentrations reduced to regulatory levels.
• can only be used for soils with good porosity for air flow.