Site Remediation Flashcards

A permeable reactive barrier (PRB) using zero-valent iron (ZVI) remediates chlorinated solvents primarily through which mechanism?

Answer: Reductive dechlorination via electron donation from iron

ZVI donates electrons to chlorinated compounds, causing reductive dechlorination that breaks chlorine-carbon bonds and produces less-toxic or non-toxic daughter products.

In a remedial investigation, what is the primary purpose of installing groundwater monitoring wells in a transect downgradient of the source area?

Answer: To delineate the contaminant plume extent and direction

Downgradient transect wells define the lateral and vertical extent of the dissolved-phase plume, confirming contaminant migration pathways.

Which RCRA corrective action document establishes the final cleanup standards and schedule for a facility subject to a corrective action order?

Answer: Corrective measures implementation (CMI) plan

The CMI plan details the selected corrective measures, implementation schedule, and performance standards that a RCRA facility must achieve.

Thermal in situ remediation techniques such as electrical resistance heating (ERH) are most advantageous for which contaminant class?

Answer: Chlorinated solvents with low vapor pressure in low-permeability soils

ERH heats the subsurface to increase volatility of chlorinated solvents, enabling vapor extraction even from tight, low-permeability formations where other methods fail.

Risk-based corrective action (RBCA) frameworks allow remediation to a site-specific risk level rather than a generic standard. What primary factor drives site-specific cleanup levels?

Answer: Exposure pathways, receptor populations, and contaminant toxicity

RBCA tier calculations incorporate contaminant toxicity, site-specific exposure pathways, and sensitive receptors to derive protective cleanup levels tailored to actual risk.

Which document formally records the deed restriction or land use control (LUC) placed on a remediated property to limit future land use?

Answer: Environmental covenant or deed restriction

An environmental covenant or deed restriction is recorded with the property deed to legally restrict land use and protect the integrity of the remedy.

Monitored natural attenuation (MNA) relies on which natural processes to reduce contaminant concentrations without active intervention?

Answer: Biodegradation, dispersion, dilution, sorption, and volatilization

MNA harnesses naturally occurring physical, chemical, and biological processes to reduce contaminant mass, toxicity, mobility, or concentration over time.