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Soil Contamination & Remediation Flashcards

7 cards from real CES 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 & Remediation flashcards as text

  1. Which biological process is responsible for converting trichloroethylene (TCE) to vinyl chloride under anaerobic conditions?

    Answer: Reductive dechlorination

    Reductive dechlorination is the anaerobic microbial process in which chlorine atoms are sequentially removed from TCE, producing DCE isomers, then vinyl chloride (VC), and ultimately ethene.

  2. A site manager wants to use thermal treatment to remediate a source zone with high-concentration PCE. Which method delivers heat to the subsurface using electrical resistance?

    Answer: Electrical resistance heating (ERH)

    Electrical resistance heating passes alternating electrical current between electrode arrays installed in the soil, generating heat through resistance to volatilize and remove contaminants.

  3. What is the role of a 'permeable reactive barrier' (PRB) in groundwater remediation?

    Answer: It is a reactive material installed across a plume flow path that degrades or immobilizes contaminants as groundwater passes through

    A PRB is a subsurface zone of reactive material (e.g., zero-valent iron) installed perpendicular to groundwater flow so that the plume passes through and contaminants are destroyed or captured in situ.

  4. Which of the following exposure pathways is typically evaluated in a residential soil risk assessment but NOT in a commercial/industrial assessment?

    Answer: Ingestion of contaminated soil by children

    Child soil ingestion is a residential-specific exposure pathway because children are present and engage in hand-to-mouth behavior at homes, whereas commercial/industrial sites assume adult workers without young children.

  5. Landfarm remediation of petroleum-contaminated soil relies primarily on which process?

    Answer: Aerobic biodegradation by indigenous soil microorganisms

    Landfarming periodically tills contaminated soil spread in thin lifts to aerate it and distribute nutrients, stimulating aerobic microbial degradation of petroleum hydrocarbons.

  6. The presence of free-phase NAPL in soil samples is most reliably confirmed in the field by:

    Answer: Visual sheen or oily residue on sample surfaces and positive Sudan IV dye test

    Visual confirmation of sheen or oily residue combined with a Sudan IV (oil-red dye) test, which stains free-phase petroleum orange-red, provides direct field evidence of NAPL presence.

  7. Which Superfund remedy selection principle requires that the chosen remedy protect human health and the environment over both the short and long term?

    Answer: Overall protectiveness

    Overall protectiveness of human health and the environment is the threshold criterion for CERCLA remedy selection — a remedy that fails this criterion cannot be selected regardless of other considerations.