DEQ Soil and Land Contamination 2 — Questions and Answers
Question 1: What is a 'risk-based cleanup' approach to contaminated site remediation?
- Cleaning all sites to the same background concentration regardless of intended land use
- Setting site-specific cleanup goals based on the actual risk posed to human health and the environment given the anticipated land use (Correct answer)
- Cleaning only sites that pose an immediate threat of explosion or fire
- Removing all contaminated material until laboratory results show non-detect for all compounds
Correct answer: Setting site-specific cleanup goals based on the actual risk posed to human health and the environment given the anticipated land use
Risk-based cleanup sets remediation goals based on site-specific exposure scenarios, risk calculations, and intended land use, allowing more cost-effective remediation while ensuring adequate health protection.
Question 2: Which regulatory program specifically addresses underground storage tanks (USTs) and their associated release response?
- RCRA Subtitle C hazardous waste program
- RCRA Subtitle I UST program, implemented by state DEQs (Correct answer)
- CERCLA Superfund emergency removal program
- EPCRA community right-to-know program
Correct answer: RCRA Subtitle I UST program, implemented by state DEQs
RCRA Subtitle I established the federal UST program, delegated to state DEQs, requiring tank registration, release detection, financial assurance, and release response procedures.
Question 3: What is 'pump and treat' technology for contaminated groundwater remediation?
- Injecting chemical oxidants into the aquifer to destroy contaminants in place
- Extracting contaminated groundwater, treating it above ground to remove contaminants, and then discharging or reinjecting the treated water (Correct answer)
- Installing physical barriers to prevent contaminant migration beyond the site boundary
- Applying microbial cultures to biodegrade contaminants within the saturated zone
Correct answer: Extracting contaminated groundwater, treating it above ground to remove contaminants, and then discharging or reinjecting the treated water
Pump and treat extracts contaminated groundwater, treats it using methods such as air stripping or activated carbon, and manages the treated effluent, providing hydraulic control and mass removal.
Question 4: What does 'plume' refer to in the context of groundwater contamination?
- A smokestack emission from an industrial facility near a contaminated site
- The three-dimensional zone of contaminated groundwater that has migrated downgradient from the source area (Correct answer)
- The visible sheen of petroleum floating on a pond surface
- A soil vapor extraction system that draws vapors from beneath a building
Correct answer: The three-dimensional zone of contaminated groundwater that has migrated downgradient from the source area
A contaminant plume is the body of contaminated groundwater that spreads downgradient from a contamination source, shaped by groundwater flow patterns and contaminant properties.
Question 5: What is soil vapor extraction (SVE) used to remediate?
- Heavy metals in surface soils at smelter sites
- Volatile organic compounds (VOCs) in the vadose zone by drawing air through contaminated soil (Correct answer)
- Dense non-aqueous phase liquids (DNAPLs) pooled in fractured bedrock
- Polychlorinated biphenyls (PCBs) in river sediments near old industrial sites
Correct answer: Volatile organic compounds (VOCs) in the vadose zone by drawing air through contaminated soil
SVE applies a vacuum to extract volatile contaminants from the unsaturated (vadose) zone soil, typically used for petroleum hydrocarbons and chlorinated solvents with sufficient vapor pressure.
Question 6: What is the 'National Priorities List' (NPL) and how does a site get listed?
- A DEQ ranking of all permitted facilities by environmental risk
- A federal list of the nation's most contaminated hazardous waste sites eligible for Superfund cleanup funding, based on the Hazard Ranking System score (Correct answer)
- A list of active enforcement cases with pending cleanup orders
- A registry of all RCRA-permitted treatment, storage, and disposal facilities
Correct answer: A federal list of the nation's most contaminated hazardous waste sites eligible for Superfund cleanup funding, based on the Hazard Ranking System score
The NPL identifies priority contaminated sites eligible for federal Superfund remedial action, with listing based on Hazard Ranking System scores that evaluate contamination severity and population exposure.
DEQ Soil and Land Contamination 2
What is a 'risk-based cleanup' approach to contaminated site remediation?