Section 2: Evaluating Contamination and Remedial Endpoints Flashcards
CSM
Conceptual Site Model
Purpose of a CSM (3 main)
- Visual representation - What media is affected, Receptors, contamination points
- understand potential pathways and routes of exposure
- serves as a guide to the design of sampling programs
Process of Vadose atmosphere to vadose soil
a) solubilization
b) sorption
c) volatization
b) sorption
AEP’s 4 points of interests regarding CSMs
- Contamination sources and types
- DNAPL or LNAPL
- Groundwater pathway
- Soil Vapour Intrusion Pathway
considerations of CSM 8.
- Media
- soil/geological conditions
- hydrogeology
- contaminate conditions
- Contaminate locations
- receptor locations
- Receptors of concern
- Expose pathways
NAPL
Non-Aqueous Phase Liquid
Most NAPLs are ________ in water
immisable- exist as a separate phase when spilled in the soil
DNAPL
Dense Non-aqueous phase liquid
Cruse oil
LNAPL
Light non-aqueous phase liquid
gasoline
What is a source of long term dissolved contamination plumes
NAPLS
________ from soil phase to aqueous or vapor phase
partitioning
Below water table contaminates move via _____
advection
LNAPLs and DNAPLs move via what two forces
gravitational and capillary forces
How do NAPLs exist as solids
adsorb or partition on soil particles- coats
How do NAPLs exist as liquids
based on their solubility, they may be able to dissolve
How do NAPLs exist as air
Volitize and trapped in pore space
_______ is the cause for the three components of soil (solid, liquid, air) to become also contaminated
Partitioning
Partitioning increases NAPL mobility (t/F)
False. It actually causes contaminates to slow or immobilize
For NAPL to continue downward it must ____ water
Displace
What two factors limit the verticle movement of LNAPLs
Light specific gravity, Buoyancy force and water content of the soil. Moves more laterally
Which way do LNAPLs move?
Laterally and with the groundwater table
Denser than water, DNAPLS go past the groundwater to the bedrock (T/F)
True
What will DNAPLs do in fine grained soils?
migrate along the top of fine soils and form pools
Residual saturation
When DNAPL no longer holds together as a continuous phase but rather is present as isolated residual globules
Residual saturation can lead to the immobilization of a DNALP in what zone
Vados
Leaching or water table fluctuations causing residual saturation of DNALPs to go from solid into the water table is called….
solubilization
Vapour phase is a function of 3 factors
- volatization properties of NAPL
- how much coats the soil
- pore spaces and temperature
Primary mechanism for vapour transport
gaseous diffusion- wants to reach equilibrium (high to low concentrations)
remediation target values are called
remedial endpoints
three main remedial endpoints/goals
- what technology is feasible
- Time and cost required
- determine when remediation is complete
where you want to get with clean up is based on tier guidelines and based on:
Land use, soil type, g/w depth, surface water, pathways
Movement of vapours is represented by
partition coefficient
