ETC Soil & Groundwater Remediation 2

Question 1

What is the difference between LNAPL and DNAPL in groundwater contamination scenarios?

Accepted Answer

LNAPL floats on the water table; DNAPL sinks below it

Answer

LNAPL sinks below the water table; DNAPL floats on top

Answer

LNAPL dissolves readily; DNAPL does not dissolve

Answer

LNAPL is always petroleum; DNAPL is always chlorinated solvents

Question 2

In groundwater monitoring, what is the purpose of a 'sentinel well' placed downgradient of a remediation system?

Accepted Answer

To detect contaminant migration beyond the treatment zone

Answer

To inject clean water to dilute the plume

Answer

To measure the aquifer pumping rate

Answer

To collect representative background samples

Question 3

Which EPA guidance document provides the framework for evaluating risk at contaminated sites to establish cleanup levels protective of human health?

Accepted Answer

EPA Risk Assessment Guidance for Superfund (RAGS)

Answer

ASTM E1527 Phase I ESA Standard

Answer

RCRA Corrective Action Plan

Answer

OSHA Process Safety Management Standard

Question 4

Enhanced bioremediation of chlorinated solvents often involves injecting an electron donor such as vegetable oil or molasses. What process does this stimulate?

Accepted Answer

Anaerobic reductive dechlorination

Answer

Aerobic oxidation of contaminants

Answer

Chemical hydrolysis of chlorinated bonds

Answer

Photolytic degradation of solvents

Question 5

What does the term 'plume diving' describe in a groundwater contamination scenario?

Accepted Answer

Contaminant sinking into deeper aquifer units due to density or recharge

Answer

Rapid spread of contamination along preferential flow paths

Answer

Natural attenuation reducing contaminant concentrations vertically

Answer

A remediation strategy using deep injection wells

Question 6

Which type of soil boring technique uses a hollow stem to advance through soil while simultaneously collecting continuous soil samples?

Accepted Answer

Hollow-Stem Auger (HSA)

Answer

Direct Push Technology (DPT)

Answer

Rotary Air Blast (RAB)

Answer

Cable Tool Drilling