L4 - Contaminated Land

Question 1

What is contaminated land defined as?

Answer 1

Significant harm has been caused to land or water

Question 2

What is a brownfield site?

Answer 2

Land that was occupied by a permanent structure

Question 3

What is the UK target for derelict land?

Answer 3

60% of new housing should be build on brownfield sites

Question 4

Examples of when contaminated land become a big problem?

Answer 4

Contamination of rivers by oil
Air by VOCs
Adjacent land with organic waste
Smells
Unable to reuse

Question 5

What does the Environmental protection act (1990) say?

Answer 5

Regulatory bodies can request clean up

Question 6

What is the regolith?

Answer 6

Part between surface and bedrock

Question 7

What is the regolith subdivided into?

Answer 7

Saturated zone - water fills all pores

Unsaturated or vadose zone

Question 8

What is soil composed of?

Answer 8

Solid phase - minerals, plant roots, organic matter - provides framework of soil forming pores shared by liquid and gas phase

Question 9

How can soil conditions vary around the world?

Answer 9

Water and oxygen - 0% to saturated
Temp - -40 to 65
pH - 2.5 to 11

Question 10

What are the features of soil microbiology

Answer 10

Decrease in number with depth
Bacteria and fungi contribute the greatest to mineralisation activity
Usually oligotrophic
Low nutrient envi means microbial pop must be dormant until more nutrients appear

Question 11

What are contaminants similar to fuel oil?

Answer 11

BTEX - benzene, toluene, ethylbenzene, xylene

DNAPLs - dense non aqueous phase liquids (usually chlorinated solvents) - don’t float on water

Question 12

What are examples of major oil spills?

Answer 12

Exxon Valdez - Alaska (1989) - 35000 tonnes
Sea Empress (1996) 65000 t
Deepwater horizon - gulf of mexico (2010) 780000 m3

Question 13

Answer : 250000

Answer 13

Number of underground tanks at petrol stations estimated to be leaking in the US

Question 14

What is the problem with terrestrial oil leakage?

Answer 14

Eventually reaches the water table

Question 15

Features of surface transport of oil?

Answer 15

Travels across surface with out penetrating soil

Common when ground is waterlogged or frozen

Question 16

Features of subsurface transport of oil?

Answer 16

Sinks through vadose zone to rest on water table

Forms a pancake flowing in direction of ground water

Question 17

What is photodecomposition of oil?

Answer 17

Result of photoxidation

Addition of hydroxyl groups to aromatics and removal of hydrogen

Question 18

What is intrinsic remediation?

Answer 18

Oil degraded by naturally occurring microbial population

Question 19

What happens with plants and hydrocarbons?

Answer 19

Take them up either passively in aqueous phase or by partitioning into organic phase of cell wall
Compounds remain in roots or are translocated to shoots and leaves

Question 20

Define adsorption

Answer 20

Retention of solutes originally present in solution by surfaces of a solid material

Question 21

Define absorption

Answer 21

Retention of solute within the mass of a solid rather than on its surfaces

Question 22

What is volatilisation?

Answer 22

Remove lighter products components of oil

Increases viscosity of oil resulting in decreased infiltration

Question 23

What are the stages of choosing a remediation strategy?

Answer 23

Desk top study
Preliminary site investigation
Detailed site investigation

Question 24

What are the features of a desk top study?

Answer 24

Searching of records
Historical maps
Local consultation

Question 25

Features of a preliminary site investigation?

Answer 25

Limited sampling
Analysing samples (expensive)
Directed by historical info

Question 26

What pollution does a coking works produce?

Answer 26

Entrained tar

Noxious liquids

Question 27

What parameters are tested to test the optimal conditions for bioremediation?

Answer 27

Use a 100g flask scale
aeration
seeding with degrading organisms
Different nutrient addition regimes

Question 28

What are microcosm and mesocosm trials?

Answer 28

Small scale trials controlling system

Measurements made of degredation rates but also see if any become mobile

Question 29

What is a field scale trial?

Answer 29

To test new treatment technology, funded by authorities