CHMM Site Remediation 5

Question 1

Under EPA's Superfund removal action authority, what is the maximum expenditure allowed for a standard removal action before a remedial action must be initiated?

Accepted Answer

$2 million

Answer

CERCLA limits standard removal actions to $2 million and 12 months unless the EPA Administrator determines that additional action is necessary.

Question 2

Phytoremediation using plants to uptake and concentrate metals in above-ground biomass is specifically called what?

Accepted Answer

Phytoextraction

Answer

Phytoextraction uses hyperaccumulator plants to take up metals from soil into harvestable shoot tissue, which is then removed and disposed of to reduce soil metal concentrations.

Question 3

A remedy that relies on engineered containment (cap and barrier walls) with no active treatment is evaluated most critically under which NCP criterion?

Accepted Answer

Reduction of toxicity, mobility, or volume through treatment

Answer

NCP favors treatment that permanently reduces contaminant hazards; containment-only remedies score lower on reduction of toxicity, mobility, or volume, requiring strong justification.

Question 4

Which type of groundwater model is most appropriate for predicting the long-term migration of a dissolved contaminant plume in a heterogeneous aquifer?

Accepted Answer

Numerical flow and transport model incorporating site-specific heterogeneity

Answer

Numerical models discretize the aquifer into cells that can represent spatial variability in hydraulic conductivity and other parameters affecting contaminant transport.

Question 5

When evaluating the toxicity of a contaminant mixture at a Superfund site, EPA typically applies what approach to combine individual chemical risks?

Accepted Answer

Hazard quotient addition (hazard index) for non-carcinogens and risk addition for carcinogens

Answer

The hazard index sums individual hazard quotients for non-carcinogens, and individual cancer risks are summed for carcinogens, giving a cumulative mixture risk estimate.

CHMM - Certified Hazardous Materials Manager Practice Test

CHMM - Certified Hazardous Materials Manager Practice Test

CHMM Site Remediation 5