CEI CEI Hazardous Materials & Remediation 2 — Questions and Answers
Question 1: Under RCRA, which category of hazardous waste is defined by specific characteristics such as ignitability, corrosivity, reactivity, or toxicity?
- Listed waste
- Characteristic waste (Correct answer)
- Universal waste
- Mixed waste
Correct answer: Characteristic waste
Characteristic hazardous wastes are defined by four measurable properties — ignitability, corrosivity, reactivity, and toxicity — rather than appearing on a specific EPA list.
Question 2: What is 'pump and treat' commonly used to accomplish during groundwater remediation?
- Inject oxygen into the saturated zone to accelerate biodegradation
- Extract contaminated groundwater and treat it above ground before discharge (Correct answer)
- Pump fresh water in to dilute contaminants
- Treat soil by pumping steam through the vadose zone
Correct answer: Extract contaminated groundwater and treat it above ground before discharge
Pump and treat systems extract contaminated groundwater to the surface, treat it using physical or chemical processes, and then discharge or reinject the treated water.
Question 3: Which term describes the concentration of a contaminant in soil or water at which no adverse health effects are expected over a lifetime of exposure?
- Maximum Contaminant Level (MCL)
- Risk-Based Cleanup Level (RBCL) (Correct answer)
- Action Level (AL)
- Threshold Limit Value (TLV)
Correct answer: Risk-Based Cleanup Level (RBCL)
Risk-Based Cleanup Levels are site-specific concentrations calculated using toxicological data and exposure assumptions to be protective of human health.
Question 4: What is the role of a Potentially Responsible Party (PRP) under CERCLA?
- A state agency that oversees remediation projects
- An entity that may be held liable for cleanup costs at a Superfund site (Correct answer)
- A consultant hired to conduct environmental assessments
- A contractor certified to handle hazardous materials
Correct answer: An entity that may be held liable for cleanup costs at a Superfund site
PRPs include current and former owners/operators, generators, and transporters who may be held jointly and severally liable for cleanup costs under CERCLA.
Question 5: During a Phase II Environmental Site Assessment, what activity distinguishes it from a Phase I?
- Reviewing regulatory database records
- Conducting interviews with site owners
- Collecting and analyzing environmental samples (Correct answer)
- Performing a visual site inspection
Correct answer: Collecting and analyzing environmental samples
A Phase II ESA involves actual collection and laboratory analysis of soil, groundwater, or building material samples to confirm or refute suspected contamination identified in Phase I.
Question 6: Which remediation approach uses natural attenuation processes — biodegradation, dilution, sorption — to reduce contaminant concentrations without active intervention?
- In-situ chemical oxidation (ISCO)
- Monitored Natural Attenuation (MNA) (Correct answer)
- Thermal desorption
- Solidification/stabilization
Correct answer: Monitored Natural Attenuation (MNA)
Monitored Natural Attenuation relies on naturally occurring physical, chemical, and biological processes to reduce contaminant levels while performance is verified through a monitoring network.
CEI CEI Hazardous Materials & Remediation 2
Under RCRA, which category of hazardous waste is defined by specific characteristics such as ignitability, corrosivity, reactivity, or toxicity?