Site Investigation

Question 1

What are the 5 main categories of contaminants?

Answer 1

Organics
Inorganics
Gases
Radionuclides
Heavy Metals

Question 2

What is the difference between -ite and -ate suffix molecules?

Answer 2

-ite has one less oxygen than -ate

Question 3

What are the 6 key sources of organic contamination?

Answer 3

Petrochemical manufacture
Solvents
Pesticides
Coal tar
Transformer fluids
Flame retardants

Question 4

What are the hydrocarbon prefixes that denote 1, 2, 3 and 4 carbon atoms respectively?

Answer 4

Meth-
Eth-
Prop-
But-

Question 5

How is a Haloalkane different from an Alkane and why is this distinction important?

Answer 5

Haloalkanes have a halogen in place of some of the hydrogen atoms
Alkanes are hydrophobic but haloalkanes may not be

Question 6

What makes something an aromatic compound?

Answer 6

It contains at least one benzene ring

Question 7

What is the structure of a benzene ring?

Answer 7

6 carbon atoms with alternating single and double bonds. The electrons are found in a cloud in the centre

Question 8

What is the technical correct name for Polyaromatic Hydrocarbons and what are they?

Answer 8

Polycyclic Aromatic Hydrocarbons
Hydrocarbons with multiple benzene rings

Question 9

Why are PFAS and PFOS problematic?

Answer 9

They are both toxic at low concentrations and non-biodegradable

Question 10

How is the hydrophobicity of a liquid measured?

Answer 10

Observing the partition coefficient between water and octanol

Question 11

What is the technical name for an emulsifier?

Answer 11

A surfactant

Question 12

How does the partition coefficient P define the lipid and water phases?

Answer 12

log P > 0: Lipid Phase
log P < 0: Water Phase

Question 13

Name 5 types of chemical reaction

Answer 13

Combustion
Synthesis
Decomposition
Single Displacement
Double Displacement

Question 14

What does the acronym OIL RIG mean?

Answer 14

Oxidation Is Loss, Reduction Is Gain (of electrons)

Question 15

What is a more comprehensible representation of 1ppm (part per million)?

Answer 15

1 milligram per kilogram

Question 16

What are the 5 geological layers considered for decontamination?

Answer 16

Ground Surface
Vadose Zone
Capillary Fringe
Saturated Zone
Confining Bed

Question 17

What is true of water in the Capillary Fringe region?

Answer 17

It is not free to move, as it is held there by surface tension

Question 18

What are NAPLs? What are the 2 key types?

Answer 18

Non-Aqueous Phase Liquids
Dense and Light

Question 19

What is true of non-aqueous contaminants that are in contact with water?

Answer 19

Small amounts of the contaminant will dissolve in the water even though the main plume is hydrophobic

Question 20

What is the difference between porosity and permeability?

Answer 20

Porosity defines the amount of void space in a soil or rock, permeability defines the freedom of fluids to pass through a soil or rock

Question 21

What is likely to happen with non-aqueous liquid contaminants passing through drained soil?

Answer 21

Residues of the contaminant will be left behind

Question 22

What must be true for a dense, non-aqueous liquid contaminant to penetrate into saturated soil?

Answer 22

The pressure head of the contaminant exceeds the capillary pressure of the water

Question 23

What is the condition for considering something a risk during risk assessment?

Answer 23

There is significant potential of significant harm

Question 24

In what context is a conceptual site model created?

Answer 24

The final use case, not the current use case

Question 25

What areas should be included in desk studies?

Answer 25

The site itself and relevant areas adjacent to the site

Question 26

Why are children classified differently to adults when assessing risk?

Answer 26

Children are more susceptible to illness from contamination due to having lower body mass

Question 27

What are the 3 phases of a risk assessment?

Answer 27

Phase 1: Preliminary Phase 2: Generic Quantitative Phase 3: Detailed Quantitative

Question 28

What does quantitative mean in the context of a risk assessment?

Answer 28

Samples are taken, tests performed and results are found

Question 29

What non-targeted sampling strategy is theoretically the best?

Answer 29

A herringbone pattern of sampling

Question 30

Why is it not necessary to drill a large number of boreholes in cases of groundwater contamination?

Answer 30

The contamination is largely homogenous, so the boreholes are only needed to establish flow direction

Question 31

Why may it be important to implement long-term gas monitoring on a site?

Answer 31

Seasonal changes in temperature can affect the volatilisation of liquids into gases

Question 32

Why might samples need to be analysed quickly or frozen?

Answer 32

Microbes can degrade the contaminant within the sample

Question 33

What are 2 quality control measures for site investigation?

Answer 33

Field blanks - containers opened on site Collection of rinsewater Trip blanks - containers which remain closed but travel

Question 34

Describe preliminary risk assessment

Answer 34

The purpose of the preliminary risk assessment is to develop an initial conceptual model for the site and establish whether there are potentially unacceptable risks

Question 35

Explain why generic and detailed quantitative risk assessments are carried out

Answer 35

After the preliminary assessment, intrusive investigation needs to be carried out to confirm which contaminants are present, at what concentrations, how they are moving and how they could pose harm. If generic assessment is found to be unsuitable for remediation to take place, detailed risk assessment must follow

Question 36

Roughly how deep must a point of interest be below the ground surface for borehole investigation to be necessary?

Answer 36

>5m

Question 37

What are the 5 important points when selecting a sampling strategy?

Answer 37

-Whether it is targeted, random or a mix of both -What media is to be sampled -The number of samples required -Sample depth -Sample collection and storage methods

Question 38

What does Soil Adsorption Coefficient (Kd/Koc) describe?

Answer 38

It measures the mobility of a substance in soil. A very high value means it is strongly adsorbed onto soil and organic matter and does not move. A very low value means it is highly mobile in soil

Question 39

How do you make use of the Henry's Law Constant?

Answer 39

Divide atmospheric pressure by the constant to find the dissolved gas concentration. If pressure above the liquid decreases, gas will leave solution and bubble out

Question 40

What is a phenol?

Answer 40

One or more hydroxyl (OH-) bonded to a benzene ring