Soil Contamination Assessment Flashcards
7 cards from real CEA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Soil Contamination Assessment flashcards as text
What does the term 'NAPL' refer to in the context of soil and groundwater contamination?
Answer: Non-Aqueous Phase Liquid
NAPL stands for Non-Aqueous Phase Liquid, referring to contaminants such as petroleum products or chlorinated solvents that exist as a separate liquid phase from water.
Which method is used to determine the bioavailability of metals in contaminated soil for ecological risk assessment purposes?
Answer: Sequential extraction procedures
Sequential extraction procedures fractionate metals into operationally defined fractions (exchangeable, carbonate-bound, etc.) to estimate bioavailable versus non-bioavailable forms.
Under CERCLA, what document formally identifies the extent of soil contamination and recommended cleanup actions at a Superfund site?
Answer: Remedial Investigation / Feasibility Study (RI/FS)
The Remedial Investigation/Feasibility Study (RI/FS) characterizes the nature and extent of contamination and evaluates cleanup alternatives under CERCLA.
A soil sample is collected from a leaking underground storage tank (LUST) site. Which analytical suite is MOST appropriate as a first-tier screen?
Answer: Total petroleum hydrocarbons (TPH) and BTEX compounds
TPH and BTEX (benzene, toluene, ethylbenzene, xylene) are the primary contaminants of concern at LUST sites and are the standard first-tier analytical parameters.
What is 'contaminant plume diving' and why is it important during soil and groundwater assessment?
Answer: A DNAPL mass that releases dissolved-phase contamination that migrates downward
DNAPL (dense NAPL) sinks through the saturated zone and serves as a long-term source releasing dissolved-phase contamination that can extend deep into the aquifer.
Which of the following best defines the 'action level' in the context of a soil contamination assessment?
Answer: The contaminant concentration that triggers a regulatory response or cleanup obligation
An action level is the contaminant concentration in soil (or other media) at or above which regulatory agencies require investigation or remediation.
A soil borings program reveals contamination that increases with depth. What does this pattern most likely suggest?
Answer: A subsurface source such as a buried tank or pipeline leak
Contamination that increases with depth typically indicates a subsurface source (e.g., buried tank, pipeline) rather than surface deposition or runoff.