Soil & Groundwater Remediation Flashcards
6 cards from real ETC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Soil & Groundwater Remediation flashcards as text
What is the primary regulatory driver for establishing cleanup levels at most state-regulated brownfield sites in the US?
Answer: Future land use and associated risk-based exposure scenarios
Risk-based cleanup levels at brownfield sites are tied to future land use because residential scenarios (with direct contact and ingestion pathways) require more stringent cleanup than industrial scenarios.
In a pump-and-treat system, what phenomenon describes the rebound of contaminant concentrations in extracted groundwater after pumping is reduced or stopped?
Answer: Concentration rebound
Concentration rebound occurs when contaminant levels in extracted groundwater rise after pumping rates are reduced, indicating continued mass flux from residual source zones or back-diffusion from low-permeability zones.
Which regulatory program under CERCLA establishes a fund (often called the 'Superfund') to pay for cleanup of contaminated sites when no viable responsible party can be found?
Answer: CERCLA Section 104 Hazardous Substance Response Trust Fund
CERCLA Section 104 established the Hazardous Substance Response Trust Fund, commonly called Superfund, which EPA uses to finance cleanups when responsible parties are unidentifiable or non-cooperative.
When conducting a soil gas survey to delineate a subsurface VOC contamination plume, what is the significance of detecting vinyl chloride (VC) at elevated concentrations?
Answer: It is a toxic degradation product of chlorinated solvents under anaerobic conditions
Vinyl chloride is the final chlorinated breakdown product of PCE and TCE under sequential reductive dechlorination, and its presence confirms anaerobic degradation of chlorinated solvents in the subsurface.
A geologist logs a soil core and describes a layer with 30% gravel, 50% sand, 15% silt, and 5% clay. Using USDA textural classification, this material would most likely be classified as:
Answer: Gravelly sandy loam
With dominant sand and significant gravel content, this material would be classified as a gravelly sandy loam, reflecting both the coarse texture and the gravel modifier in USDA soil taxonomy.
What is institutional controls (ICs) in the context of site remediation, and when are they typically implemented?
Answer: Legal or administrative mechanisms that restrict land or resource use when contamination remains above unrestricted use levels
Institutional controls are non-engineering measures such as deed restrictions, zoning ordinances, or well use prohibitions that limit exposure to residual contamination when full cleanup to background levels is not achieved.