CES CES Environmental Site Assessment & Investigation 2 — Questions and Answers
Question 1: What is the purpose of a soil vapor survey during environmental site investigation?
- To detect volatile organic compounds in subsurface soil gas (Correct answer)
- To measure soil load-bearing capacity for construction
- To assess soil pH for agricultural land use
- To determine saturated hydraulic conductivity
Correct answer: To detect volatile organic compounds in subsurface soil gas
Soil vapor surveys detect VOCs that have volatilized from contaminated soil or groundwater into the subsurface gas phase, informing vapor intrusion evaluations.
Question 2: What subsurface features does ground-penetrating radar (GPR) detect during site investigation?
- Buried tanks, utilities, and soil anomalies (Correct answer)
- Groundwater pH and dissolved oxygen levels
- Surface water flow velocities
- Ambient air quality parameters
Correct answer: Buried tanks, utilities, and soil anomalies
GPR uses electromagnetic pulses to map subsurface features including buried tanks, utilities, and lithological anomalies without intrusive drilling.
Question 3: What is the primary purpose of a 'Conceptual Site Model' (CSM) in environmental investigation?
- To integrate all site data describing contamination sources, transport pathways, and potential receptors (Correct answer)
- To produce a 3D architectural rendering of site buildings
- To serve as the legal document governing property transfer
- To define the official property boundary survey
Correct answer: To integrate all site data describing contamination sources, transport pathways, and potential receptors
The CSM synthesizes all available site information to describe contaminant sources, release mechanisms, migration pathways, and potential human or ecological receptors, guiding investigation and remediation decisions.
Question 4: Which CERCLA document formally establishes the selected cleanup approach for a Superfund site?
- Record of Decision (ROD) (Correct answer)
- Notice of Violation (NOV)
- Environmental Impact Statement (EIS)
- Preliminary Assessment (PA)
Correct answer: Record of Decision (ROD)
The Record of Decision (ROD) is EPA's formal decision document explaining which remediation alternative was selected for a Superfund site and why.
Question 5: What is the primary function of a groundwater monitoring well at a contaminated site?
- To collect water samples for tracking contaminant concentrations and plume movement (Correct answer)
- To pump out contaminated groundwater for surface treatment
- To inject remediation chemicals into the aquifer
- To measure surface water discharge rates
Correct answer: To collect water samples for tracking contaminant concentrations and plume movement
Monitoring wells are installed to collect representative groundwater samples that allow professionals to characterize contamination and track plume extent and concentration trends over time.
Question 6: What is 'secondary source contamination' in site investigation terminology?
- Residual contamination in soil or NAPL that continues releasing contaminants to groundwater after the original release stopped (Correct answer)
- The second-highest concentration zone identified during a soil boring program
- Contamination originating from adjacent neighboring properties
- Diluted contamination present at the outer edge of a groundwater plume
Correct answer: Residual contamination in soil or NAPL that continues releasing contaminants to groundwater after the original release stopped
Secondary sources are residual contaminants (sorbed phase, NAPL) that act as continuing long-term sources of dissolved-phase contamination to groundwater long after the primary release event.
CES CES Environmental Site Assessment & Investigation 2
What is the purpose of a soil vapor survey during environmental site investigation?